Buy Methotrexate Online — Foundational Folate Analog Antimetabolite for Leukemia, Lymphoma, Breast Cancer, Severe Rheumatoid Arthritis & Severe Psoriasis

The four main modern uses of Methotrexate

• 🦴 Rheumatoid arthritis and other autoimmune disease - foundational DMARD taken as a weekly low dose (7.5-25 mg)
• 🩹 Severe psoriasis and psoriatic arthritis - weekly low dose in dermatology
• 🎗️ Cancer chemotherapy - much higher doses (up to grams per square metre) with leucovorin rescue; leukaemia, lymphoma, breast cancer, osteosarcoma, and other malignancies
• 🏥 Ectopic pregnancy and gestational trophoblastic disease - single or multi-dose regimens as outpatient alternative to surgery

Rheumatoid arthritis and inflammatory arthritis

The largest global use by client numbers. Methotrexate is the anchor first-line DMARD in adult rheumatoid arthritis per ACR and EULAR guidelines. It works both as monotherapy and as the backbone of combinations with biologics (TNF inhibitors, IL-6 inhibitors) and targeted synthetic DMARDs (JAK inhibitors). Also used in juvenile idiopathic arthritis, psoriatic arthritis, and ankylosing spondylitis peripheral disease. Section 4 covers RA in depth.

Severe psoriasis and psoriatic arthritis

Second-line after topical therapy and phototherapy in moderate-to-severe plaque psoriasis, and one of the DMARDs of choice in psoriatic arthritis. Weekly low-dose regimen mirrors rheumatoid arthritis dosing. Section 5 covers dermatology and PsA use.

Cancer chemotherapy

The oldest use. Methotrexate features across a wide range of malignancies:

• Acute lymphoblastic leukaemia (ALL) - high-dose IV methotrexate and intrathecal methotrexate for CNS prophylaxis; foundational to childhood and adolescent ALL protocols
• Non-Hodgkin lymphoma - CNS prophylaxis and treatment in aggressive lymphomas
• Breast cancer - historical CMF regimen (cyclophosphamide, methotrexate, 5-FU); now largely superseded
• Osteosarcoma - high-dose methotrexate with leucovorin rescue as core protocol
• Bladder cancer - part of MVAC regimen
• Choriocarcinoma and gestational trophoblastic neoplasia - highly methotrexate-responsive
• Head and neck cancer - historical use, largely replaced

Ectopic pregnancy and gestational trophoblastic disease

Standard medical management of stable ectopic pregnancy meeting specific criteria (hCG below 5000, no fetal cardiac activity, no rupture). Also used as first-line treatment in low-risk gestational trophoblastic neoplasia after molar pregnancy. Section 6 covers this in depth.

Other autoimmune and inflammatory conditions

• Juvenile idiopathic arthritis (JIA) - weekly methotrexate is standard first-line DMARD
• Crohns disease and ulcerative colitis - second-line steroid-sparing option
• Dermatomyositis and polymyositis - immunosuppressive maintenance
• Sarcoidosis - steroid-sparing in chronic disease
• ANCA vasculitis - maintenance therapy after remission induction
• Systemic lupus erythematosus - occasional use for arthritis-dominant disease
• Uveitis - non-infectious inflammatory uveitis
• Graft-versus-host disease prophylaxis in bone marrow transplant

Why one drug for so many diseases

Methotrexate blocks DNA synthesis in dividing cells and separately calms inflammation through adenosine release. Fast-dividing cell populations - cancer cells, activated immune cells, rapidly turning-over psoriatic skin, trophoblastic tissue in an ectopic - all yield to the same drug. The mechanism explains both the breadth of use and the pattern of side effects, which mostly reflect the drug's effect on the body's own fast-dividing cell populations (bone marrow, GI lining, hair follicles).

Acute lymphoblastic leukaemia (ALL)

The founding indication and still central. Methotrexate appears throughout ALL protocols:

• Induction phase - intrathecal methotrexate as CNS prophylaxis begins early
• Consolidation phase - high-dose IV methotrexate (1000-5000 mg/m2 or higher) with leucovorin rescue
• CNS-directed therapy - repeated intrathecal methotrexate (typically 12 mg per dose) to prevent CNS relapse; replaced most cranial radiation in modern protocols
• Maintenance phase - low-dose oral or IM methotrexate weekly for 2-3 years combined with 6-mercaptopurine

Modern childhood ALL cure rates exceed 90 percent in high-income countries. Methotrexate is a large part of why.

Non-Hodgkin lymphoma

High-dose methotrexate for CNS prophylaxis in aggressive B-cell lymphomas at high CNS relapse risk (double-hit, testicular, breast involvement, high IPI). Also central to primary CNS lymphoma regimens where methotrexate crosses the blood-brain barrier at high doses. Intrathecal methotrexate for confirmed CNS disease.

Osteosarcoma

High-dose methotrexate (8-12 g/m2) with leucovorin rescue is one of the three drugs in the MAP regimen (methotrexate, adriamycin, cisplatin) that transformed osteosarcoma from a nearly universally fatal disease into one where 60-70 percent of localised cases are cured. Administration requires urinary alkalinisation, aggressive hydration, and careful serum methotrexate level monitoring.

Breast cancer

The historic CMF regimen (cyclophosphamide, methotrexate, 5-fluorouracil) was standard adjuvant chemotherapy for early breast cancer for two decades. Modern anthracycline and taxane regimens have largely replaced CMF for most clients, but the older regimen remains occasionally used in older or comorbid clients where anthracycline avoidance is preferred.

Bladder cancer

Methotrexate is one component of the MVAC regimen (methotrexate, vinblastine, adriamycin, cisplatin) for advanced urothelial cancer. Modern gemcitabine-cisplatin regimens have replaced MVAC as first-line for most clients, but dose-dense MVAC and its variants remain in the armamentarium.

Gestational trophoblastic neoplasia

Choriocarcinoma and other GTN are among the most chemosensitive tumours known. Single-agent methotrexate cures nearly all low-risk GTN. This remarkable responsiveness makes methotrexate first-line here even in the modern era.

High-dose methotrexate needs leucovorin rescue

At oncology doses methotrexate would kill normal cells without rescue. Leucovorin (folinic acid) bypasses the DHFR blockade in normal cells, restoring folate metabolism and rescuing bone marrow and GI lining. Timing is critical - leucovorin usually begins 24 hours after methotrexate. Serum methotrexate levels are measured to guide leucovorin dosing and duration. Kidney function must be preserved because methotrexate is renally cleared.

What the guidelines say

Both the American College of Rheumatology (ACR) 2021 guidelines and the European Alliance of Associations for Rheumatology (EULAR) 2022 recommendations place methotrexate as first-line therapy for newly diagnosed rheumatoid arthritis. Specifically:

• Methotrexate monotherapy is the first choice unless contraindicated
• Escalation to combination therapy (biologic or JAK inhibitor plus methotrexate) when methotrexate alone is inadequate
• Methotrexate remains the backbone even when biologics are added - because biologics work better with methotrexate than alone
• Treat-to-target approach with regular disease activity measurement

The Weinblatt trial that changed rheumatology

The 1985 double-blind placebo-controlled trial by Michael Weinblatt and colleagues (NEJM 1985) was the turning point. Methotrexate substantially improved joint counts, pain, and function versus placebo in adults with established RA. A parallel trial by Williams and colleagues confirmed the finding. Together these papers established methotrexate as a genuine disease-modifying drug and opened the modern era of RA treatment where preventing joint damage became a realistic goal.

How methotrexate works in RA at low weekly doses

At the doses used in rheumatology (7.5-25 mg once weekly), the mechanism is not primarily DNA synthesis blockade. Instead:

• Adenosine release - methotrexate blocks a step in purine metabolism that leads to increased extracellular adenosine, which is strongly anti-inflammatory
• T-cell suppression - reduces activated T-cell proliferation in synovium
• Cytokine modulation - reduces TNF-alpha, IL-6, and other inflammatory cytokines
• Reactive oxygen species reduction in inflamed joints
• Anti-angiogenic effects on pannus formation

Typical RA dosing

What to expect in RA

• 🟢 About 30-50 percent of clients reach ACR50 response (50 percent improvement in joint counts and other measures) on methotrexate monotherapy
• 🟢 Adding a biologic or JAK inhibitor to methotrexate improves response rates further
• 🟢 Long-term methotrexate slows radiographic joint damage
• 🟢 Registry data show reduced all-cause and cardiovascular mortality in RA clients on methotrexate versus untreated
• 🟡 Response is slow - do not expect improvement in the first month; give it 12 weeks
• 🟡 Roughly 20-30 percent stop methotrexate within 2 years due to side effects or inadequate response

When methotrexate is used in psoriasis

• Moderate-to-severe plaque psoriasis failing topical therapy and phototherapy
• BSA over 10 percent or PASI score in moderate-to-severe range
• Psoriasis with significant quality-of-life impact even at lower BSA (facial, genital, palmoplantar involvement)
• Psoriatic arthritis with peripheral joint involvement
• Erythrodermic or pustular psoriasis as one of the options
• Nail psoriasis with significant morbidity
• Where biologics are unaffordable, unavailable, or contraindicated (e.g., recent malignancy, active infection)

Typical dosing in psoriasis

Similar to rheumatology dosing:

• Starting dose 7.5-10 mg once weekly (or a test dose of 2.5-5 mg)
• Increase to 15-25 mg once weekly based on response
• Folic acid 5 mg weekly (day after MTX) or 1 mg daily
• Response typically seen at 6-12 weeks
• 60-70 percent PASI 75 response at week 16 in trials (though real-world numbers are lower)

Psoriatic arthritis

In psoriatic arthritis with peripheral joint involvement, methotrexate is one of the recommended DMARDs alongside sulfasalazine and leflunomide. Evidence for methotrexate in axial (spondylitis) psoriatic arthritis is weaker - biologics work better for axial disease. Combination methotrexate plus biologic is commonly used in more severe psoriatic arthritis mirroring the RA approach.

Liver monitoring is stricter in dermatology than rheumatology

Long-term methotrexate in psoriasis was historically associated with cirrhosis, particularly with cumulative doses over 1.5-2 grams. Modern dermatology guidelines rely on serial procollagen III N-terminal propeptide (PIIINP) testing or non-invasive fibrosis assessment (FibroScan, hepatic elastography) rather than the historical liver biopsy at cumulative dose thresholds. Alcohol restriction is stricter than in rheumatology, and MASLD/NAFLD screening matters. Section 18 covers liver toxicity in detail.

Biologics have changed the landscape

TNF inhibitors, IL-17 inhibitors (secukinumab, ixekizumab, bimekizumab), IL-23 inhibitors (guselkumab, risankizumab, tildrakizumab), and oral small molecules (apremilast, deucravacitinib) offer response rates far exceeding methotrexate for psoriasis (PASI 90 in 70-80 percent of clients on modern biologics versus PASI 75 in 40 percent on methotrexate in real-world data). Where cost and access allow, biologics have largely replaced methotrexate as first systemic therapy in high-income countries. Methotrexate remains the workhorse in resource-limited settings and continues to be used alongside biologics in psoriatic arthritis.

Why methotrexate works for ectopic pregnancy

Trophoblastic tissue divides rapidly. Methotrexate blocks DNA synthesis in dividing cells. A single dose can halt trophoblast growth in a small, unruptured ectopic pregnancy, allowing the tissue to be resorbed by the body over weeks. The client avoids surgery, general anaesthesia, and salpingectomy in most cases.

Client selection criteria

Not every ectopic is suitable for medical management. Standard criteria include:

• 🟢 Haemodynamically stable - no signs of rupture or shock
• 🟢 Serum hCG below 5000 mIU/mL - higher levels reduce success rates
• 🟢 No fetal cardiac activity on ultrasound
• 🟢 Ectopic mass below 3.5-4 cm on imaging
• 🟢 No free fluid in the abdomen or minimal only
• 🟢 Normal baseline blood count, liver, and kidney function
• 🟢 No breastfeeding and no coexisting pregnancy that is desired
• 🟢 Ability and willingness to attend for hCG follow-up
• 🟢 No contraindication to methotrexate (immunodeficiency, active infection, pulmonary disease, peptic ulcer)

Dosing protocols

Follow-up hCG monitoring

• hCG measured at day 4 and day 7 after treatment
• Adequate response = 15 percent or greater drop in hCG between day 4 and day 7
• Weekly hCG measurement then until undetectable
• Complete resolution typically takes 4-8 weeks
• Rising or plateauing hCG signals treatment failure - repeat dose or surgery needed

Warning signs after methotrexate for ectopic

• 🔴 Sudden severe abdominal pain - possible tubal rupture; go to hospital immediately
• 🔴 Shoulder tip pain - possible intra-abdominal bleeding
• 🔴 Feeling faint or dizzy - possible haemorrhage
• 🔴 Persistent heavy bleeding
• 🔴 Fever, mouth ulcers, unusual bruising - methotrexate side effects

After methotrexate for ectopic - important rules

• Reliable contraception for at least 3 months after methotrexate - the drug is teratogenic and remains in tissues for weeks
• Avoid NSAIDs, folic acid supplements, and folate-containing multivitamins in the days after treatment
• Avoid strenuous exercise and sexual intercourse until hCG resolves
• Alcohol restriction during treatment period
• Attend all follow-up hCG appointments - drop-off from follow-up is dangerous

The folate pathway in one paragraph

Folic acid (vitamin B9) is essential for making thymidine and purines - the building blocks of DNA. Dietary folate enters cells, is converted to dihydrofolate (DHF), then converted by DHFR to tetrahydrofolate (THF), the active form. THF donates one-carbon units for synthesis of thymidine (a DNA base) and purines (adenine, guanine). Without active THF, cells cannot make new DNA and cannot divide.

What methotrexate does step by step

1. Enters cells through the reduced folate carrier - the same transporter that brings natural folate in
2. Undergoes polyglutamation inside cells (methotrexate polyglutamates persist for weeks - explaining why weekly dosing works)
3. Binds DHFR with very high affinity - much tighter than natural DHF does
4. Blocks conversion of DHF to THF - the folate pool becomes locked in the inactive DHF form
5. Halts thymidine and purine synthesis
6. Cells cannot make new DNA and cannot divide
7. Rapidly dividing cells die (cancer cells, activated immune cells, trophoblast)

Why cancer cells and normal cells respond differently

Cancer cells divide rapidly and need continuous DNA synthesis - they are particularly vulnerable to methotrexate. Some normal cell populations also divide rapidly (bone marrow, intestinal lining, hair follicles) and these are where methotrexate side effects concentrate. Non-dividing cells (mature neurons, cardiac muscle) are largely spared.

The second mechanism - adenosine release

At the low weekly doses used in autoimmune disease, DNA synthesis blockade is only part of the story. Methotrexate also blocks a step in purine metabolism (AICAR transformylase) which leads to accumulation and release of extracellular adenosine. Adenosine is a potent anti-inflammatory signal that suppresses activated T-cells, macrophages, and neutrophils. This adenosine mechanism is likely the main way methotrexate helps rheumatoid arthritis at doses that barely affect DNA synthesis in most cells.

Leucovorin (folinic acid) rescue

Leucovorin (folinic acid, 5-formyl-THF) is the reduced form of folate that bypasses the DHFR blockade. Given after high-dose methotrexate, leucovorin restores folate metabolism in normal cells - which have intact folate transporters - and rescues bone marrow and GI lining from lethal toxicity. Cancer cells with reduced folate transporter expression may be relatively resistant to leucovorin rescue, allowing selective killing. Leucovorin rescue is why high-dose oncology methotrexate is tolerable at all.

Do not confuse folic acid with folinic acid (leucovorin)

Folic acid is the vitamin, given at 1-5 mg to reduce low-dose methotrexate side effects. Folinic acid (leucovorin) is the reduced active form used to rescue normal cells after high-dose oncology methotrexate. These are two different molecules with different uses. Do not substitute one for the other.

Methotrexate is dosed WEEKLY for all autoimmune indications

Rheumatoid arthritis, psoriasis, psoriatic arthritis, JIA, Crohns, sarcoidosis, and every other non-cancer indication use ONE dose ONCE per week. Daily dosing at rheumatology doses is a fatal error. The tablets look like any other pill and the mistake is very common.

Why daily dosing kills

Cumulative daily doses of what should be a weekly amount produce severe myelosuppression - bone marrow shutdown. Neutrophils, platelets, and eventually red cells fall dangerously. Sepsis and haemorrhage follow. Severe mucositis and skin necrosis develop. Without aggressive support (leucovorin, transfusions, filgrastim, intensive care) the error is often fatal. Numerous case reports and pharmacovigilance reviews from FDA, EMA, MHRA, TGA, and ISMP document deaths from this mistake year after year.

How the error happens

• Client misreads the label or forgets the weekly rhythm
• Prescription written as "methotrexate 2.5 mg daily" instead of "methotrexate 2.5 mg six tablets once weekly"
• Pharmacy dispensing error
• Family caregiver assumes daily like other medications
• Client stops on discharge from hospital and restarts wrongly
• Handover between primary care and specialist care miscommunication
• Confusion with folic acid (which IS daily in some regimens)
• Older client with cognitive difficulty and no medication supervision

Safeguards to build in

• 🟢 Take methotrexate on the same day every week - most people choose weekend or a memorable weekday
• 🟢 Weekly pillbox with only 7 slots - the compartment for the methotrexate day contains all week's tablets, other days empty
• 🟢 Store methotrexate separately from daily medications
• 🟢 Explicit label on the pack: "METHOTREXATE - WEEKLY ONLY - EVERY [DAY]"
• 🟢 Phone reminder labelled "Weekly methotrexate" with a weekly recurrence, not daily
• 🟢 Tell every doctor and pharmacist at every visit that you are on weekly methotrexate
• 🟢 Family and caregivers must know the rule - print it and stick to the fridge
• 🟢 Check every new prescription - if you see methotrexate written as daily, question it before taking

If daily dosing has been taken by mistake

1. Stop methotrexate immediately
2. Contact the treating team or attend emergency department
3. Bring the packet and tell them exactly how many doses were taken over how many days
4. Urgent blood count needed
5. Leucovorin rescue may be started immediately depending on dose and time since exposure
6. Admission for monitoring likely if any cumulative overdose has occurred

Dose ranges across indications

The three tiers of methotrexate dosing

• Low dose (7.5-25 mg WEEKLY) - autoimmune, dermatology, JIA. Oral or subcutaneous. Long-term outpatient. Folic acid supplementation. Weekly rhythm absolute.
• Intermediate dose (50-500 mg/m2) - ectopic pregnancy, some maintenance oncology protocols. IM or IV. Usually single or short-course dosing.
• High dose (1000 mg/m2 and above, up to 12 g/m2) - ALL consolidation, osteosarcoma, primary CNS lymphoma. IV in hospital only. Requires urinary alkalinisation, aggressive hydration, serum methotrexate level monitoring, and mandatory leucovorin rescue starting 24 hours after infusion.

Weight-based versus BSA-based dosing

Adult rheumatology and psoriasis use fixed weekly doses (not weight-based). Paediatric rheumatology and all oncology use body surface area (BSA) or weight-based dosing because the therapeutic window is narrower and pharmacokinetic scaling matters. High-dose oncology protocols additionally monitor serum methotrexate levels at defined timepoints to guide leucovorin duration.

Tablet strength and how doses are made up

• Oral tablets are typically 2.5 mg (some countries also 10 mg)
• A 15 mg weekly rheumatology dose = 6 tablets of 2.5 mg taken together once weekly
• A 25 mg weekly dose = 10 tablets of 2.5 mg once weekly
• Subcutaneous formulations (Otrexup, Rasuvo, Metoject) come in fixed strengths matching common weekly doses (7.5, 10, 12.5, 15, 17.5, 20, 22.5, 25, 30 mg per pen or syringe)

What folic acid supplementation prevents

• 🟢 Nausea and gastrointestinal upset
• 🟢 Mouth ulcers and stomatitis
• 🟢 Hair thinning
• 🟢 Mildly abnormal liver enzymes
• 🟢 Some myelosuppression
• 🟢 Improves long-term treatment persistence (fewer people stop methotrexate)

Common regimens

Why not the same day as methotrexate

Taking folic acid the same day as methotrexate reduces methotrexate uptake into cells (both compete for the reduced folate carrier) and can lower efficacy. Separating by at least 24 hours preserves the methotrexate effect while providing enough folate to prevent side effects in normal tissues. The methotrexate polyglutamates that persist in cells for days do not lose their effect from the following-day folate dose.

Does folic acid reduce methotrexate efficacy

A recurring concern historically, now largely resolved. The Cochrane review and multiple modern trials show that folic and folinic acid supplementation reduces side effects without meaningfully impairing efficacy. There is a very small reduction in disease activity scores in some analyses but the improvement in tolerability and long-term persistence more than compensates.

Do NOT confuse folic acid with folinic acid

Folic acid is the vitamin taken with weekly methotrexate for autoimmune indications. Folinic acid (leucovorin) is the rescue drug used after high-dose oncology methotrexate to prevent lethal toxicity. Both work at the folate pathway but they are different molecules with different roles. If your prescription says one, do not substitute the other.

Practical tips

• Take the weekly folic acid on the same day each week - the day after methotrexate is easiest to remember
• Combine dose organiser with clear labelling - two different colours help
• Do not double up if you miss a folic acid dose - just resume next scheduled dose
• Do not add extra folic acid supplements or folate-containing multivitamins without discussing with the treating team (they compete with methotrexate)
• Ectopic pregnancy protocol is different - folic acid is temporarily stopped during methotrexate treatment

Oral tablets - the standard starting point

• Usually 2.5 mg tablets taken as multiple tablets once weekly
• Cheapest option, widely available worldwide
• Absorption is 60-80 percent but variable
• Absorption saturates above 15 mg - higher oral doses give diminishing returns
• Food reduces absorption modestly (take on empty stomach or with light snack)
• Take with a full glass of water
• Do not crush, split, or handle broken tablets bare-handed (cytotoxic)

Subcutaneous injection - better tolerability at higher doses

• Pre-filled syringes (Metoject in Europe) or auto-injectors (Otrexup, Rasuvo in USA)
• Available in fixed strengths matching common weekly doses (7.5, 10, 12.5, 15, 17.5, 20, 22.5, 25, 30 mg)
• Once-weekly injection - self-administered at home after training
• Rotate injection sites (abdomen, thigh)
• Bioavailability approaches 100 percent - no absorption ceiling
• Significantly less nausea than oral
• More expensive than oral tablets

When to switch from oral to injection

• Nausea or vomiting from oral tablets not controlled by folic acid or antiemetic
• Oral dose has reached 15-20 mg weekly without adequate response - switch may boost bioavailability
• Clinical response inadequate on high oral dose
• Gastrointestinal absorption issues (inflammatory bowel disease, gastric surgery)
• Client preference and self-injection tolerance
• Client whose weekly-dosing safety is at risk with tablet packs

Intramuscular and intravenous methotrexate

• IM for ectopic pregnancy (50 mg/m2 single dose), some paediatric protocols, occasional adult rheumatology
• IV high-dose for oncology (osteosarcoma, ALL, lymphoma) in hospital only, with hydration, urinary alkalinisation, serum level monitoring, and leucovorin rescue
• Intrathecal (into cerebrospinal fluid) for CNS prophylaxis in ALL and CNS lymphoma - typically 12 mg per dose, given by specialist lumbar puncture
• These routes are not for home use - all done in clinical settings

Handling methotrexate safely at home

• 🔴 Methotrexate is cytotoxic - handle with the same care as chemotherapy
• 🔴 Do not crush or split tablets unless specifically instructed
• 🔴 Wash hands after handling tablets or injection devices
• 🔴 Do not open capsules or handle broken tablets bare-handed
• 🔴 Pregnant caregivers should avoid direct handling
• 🔴 Return unused tablets to pharmacy - cytotoxic waste stream
• 🔴 Store safely away from children
• 🔴 Used syringes and auto-injectors go in a sharps container, then returned to pharmacy

Food and methotrexate absorption

• Food reduces oral methotrexate absorption modestly (about 10-15 percent)
• Taking on an empty stomach maximises absorption
• Taking with a light meal reduces nausea in clients who feel sick on empty stomach
• Consistency matters more than the specific approach - pick one habit and stick to it
• Subcutaneous injection bypasses absorption issues entirely

Foods and supplements that interact

• 🟡 Folate-fortified foods and supplements - can reduce methotrexate efficacy at very high folate intake; normal fortified cereals fine, but avoid megadose folate supplements without discussing
• 🟡 Multivitamins containing folic acid - the folic acid your rheumatologist prescribes is enough; extra folate from multivitamins may compete
• 🟡 Caffeine - very high intake (over 300 mg/day) may modestly reduce methotrexate efficacy through adenosine receptor blockade (methotrexate's anti-inflammatory mechanism partly runs through adenosine); moderate caffeine intake is fine
• 🟢 Green tea - occasional cups fine; not a concern at usual intake
• 🟢 Normal diet - no specific restrictions beyond alcohol (see Section 13)

Hydration matters

Methotrexate is cleared by the kidneys. Good hydration (2 litres of water most days) supports renal clearance and reduces the risk of accumulation in dehydrated states. This matters particularly for older clients, hot climates, and anyone with mild renal impairment. During acute illness with vomiting or diarrhoea, methotrexate accumulation risk rises with dehydration - discuss holding a dose with your treating team.

A note on obesity and diet

Methotrexate response in rheumatoid arthritis is reduced in obesity. Weight loss improves both disease activity and methotrexate efficacy. Mediterranean-style diets with fish, olive oil, vegetables, and whole grains have modest anti-inflammatory benefit alongside methotrexate. In psoriasis, weight loss significantly improves response to systemic therapy.

Practical routine

• Same day of the week, same approximate time
• With a small snack if empty-stomach dosing causes nausea
• Full glass of water
• Folic acid the next day at the same time
• Adequate hydration through the week
• Normal balanced diet - no methotrexate-specific restrictions

The problem alcohol creates

Both methotrexate and alcohol are hepatotoxic. Together the risk of liver injury multiplies. Long-term methotrexate can cause hepatic fibrosis and, rarely, cirrhosis. Adding heavy alcohol intake substantially raises the risk. Fatty liver disease (very common in the general population) amplifies both risks.

Practical alcohol limits

Why dermatology is stricter than rheumatology

Historic psoriasis literature linked long-term methotrexate to cirrhosis at cumulative doses above 1.5 grams, with alcohol identified as the major amplifier. Rheumatology data (RA clients often already have some inflammation-related liver changes) show lower cirrhosis risk with careful monitoring. Modern guidelines are less prescriptive than the historic "total abstinence" rule but psoriasis dermatology remains stricter than RA rheumatology by convention.

Timing around the methotrexate dose

• Avoid alcohol on the day of methotrexate dose
• Avoid alcohol for 24 hours after (some guidelines say 48 hours)
• Spread any allowed weekly intake across other days rather than binging
• Binge drinking (over 4 drinks in one session) is more dangerous than the same total spread out

Rules that apply always

• 🔴 No alcohol if liver enzymes are abnormal
• 🔴 No alcohol during induction or dose escalation
• 🔴 No alcohol if you have fatty liver disease
• 🔴 No alcohol during acute illness or dehydration
• 🔴 Report honest alcohol intake to your rheumatologist - they cannot help you manage risk without knowing
• 🔴 If you are struggling to keep to advised limits, discuss with the treating team - alternatives exist

Side effect frequency in low-dose weekly regimens (RA, psoriasis)

Warning signs - contact treating team urgently

• 🔴 Fever, sore throat, or any infection symptoms - possible neutropenia
• 🔴 Unusual bruising, bleeding, or petechiae - possible thrombocytopenia
• 🔴 Severe mouth ulcers preventing eating or drinking - possible severe mucositis
• 🔴 Persistent dry cough or shortness of breath - possible pneumonitis
• 🔴 Yellow skin or eyes, dark urine, right upper quadrant pain - possible hepatotoxicity
• 🔴 Severe nausea and vomiting preventing tablet intake for over 24 hours
• 🔴 Widespread skin rash or blistering - possible severe cutaneous reaction
• 🔴 Accidental daily dosing - see Section 8

Post-dose fatigue and malaise

Many rheumatology and dermatology clients report a "methotrexate fog" - fatigue, nausea, and general malaise lasting 24-48 hours after the weekly dose. Taking the dose in the evening or before a rest day helps. Folic acid supplementation, adequate hydration, and switching from oral to subcutaneous injection can reduce these symptoms substantially.

Why methotrexate causes GI upset

• Direct effect on rapidly dividing intestinal lining cells
• Depletion of gut folate stores
• Central emetic pathway activation
• More common with oral dosing than subcutaneous (bypasses first-pass GI exposure)

Practical steps that usually help

1. Confirm you are taking folic acid - the single biggest lever; 5 mg weekly (day after MTX) or 1 mg daily off-day. Improvement often within 2-4 weeks.
2. Take methotrexate in the evening - sleep through the peak nausea period
3. Split the weekly dose - some take half in morning, half 12 hours later (same day only, not spread across days)
4. Take with a small snack - not full meal (reduces absorption too much)
5. Antiemetic 30 minutes before dose - ondansetron 4-8 mg, metoclopramide 10 mg, or cyclizine as prescribed
6. Switch to subcutaneous injection - bypasses GI absorption; nausea often improves significantly
7. Increase folinic acid instead of folic acid - some clients tolerate folinic acid rescue better than folic acid
8. Dose reduction - as a last resort if the above fails

Diarrhoea specifically

Less common than nausea but does occur. Usually settles within 2-3 days. Persistent diarrhoea (over a week) or blood in stool warrants review. Rule out infection. Consider methotrexate dose reduction. Rare cases of methotrexate-associated enteritis need drug discontinuation.

When to worry about nausea

• 🔴 Nausea with severe abdominal pain
• 🔴 Vomiting preventing all oral intake for over 24 hours
• 🔴 Nausea with jaundice or right upper quadrant pain (liver signal)
• 🔴 Coffee-ground vomit or blood in vomit
• 🔴 Rapid weight loss
• 🔴 Signs of dehydration (thirst, dizziness, low urine output)

The spectrum

• 🟢 Mild - one or two small ulcers, resolve in a week; annoying but manageable
• 🟡 Moderate - multiple ulcers, painful, interfere with eating; usually resolve with dose reduction and folic acid optimisation
• 🔴 Severe - widespread painful ulceration, difficulty swallowing, weight loss risk; often signals overdose, drug interaction, or renal impairment causing methotrexate accumulation

Severe stomatitis is a red flag

Widespread painful oral ulceration in a client on methotrexate is a warning sign for methotrexate toxicity from overdose, drug interaction, or renal impairment. Urgent blood tests including full blood count, liver enzymes, and creatinine. Consider daily-dosing error (Section 8), NSAID interaction (Section 23), trimethoprim-sulfamethoxazole co-prescription (Section 22), or a sudden fall in kidney function.

Managing mild-to-moderate mouth ulcers

• Optimise folic acid supplementation first
• Chlorhexidine mouthwash twice daily helps healing
• Benzydamine mouthwash for pain
• Ice chips or cold water before eating
• Avoid spicy, acidic, or hot foods until healed
• Soft, cool foods (yogurt, smoothies, soft eggs)
• Alcohol-free mouthwashes only
• Good oral hygiene despite the pain - soft toothbrush
• Report to treating team if recurrent

Dose adjustment for recurrent stomatitis

• Increase folic acid dose if not maximum
• Switch to folinic acid (leucovorin) rescue instead
• Switch from oral to subcutaneous injection
• Reduce methotrexate dose
• Consider alternative DMARD if persistent despite the above

Hair thinning

• Frequency 5-10 percent of clients on low-dose weekly methotrexate
• Diffuse thinning across the scalp - not the patchy hair loss of alopecia areata
• Typically noticeable at 3-6 months
• Usually mild - noticeable to the client, not always to others
• Reversible after methotrexate discontinuation - regrowth over months
• Improved by folic acid supplementation
• Severe hair loss (chemotherapy-style alopecia) does not occur at low weekly doses

Skin changes

• Photosensitivity - increased burning tendency; use SPF 50 sunscreen and cover up (Section 24 for detail)
• Skin dryness - moisturise regularly
• Nodulosis - firm subcutaneous nodules, especially on elbows and hands, in about 10 percent of RA clients on long-term methotrexate; usually harmless
• Radiation recall - previously irradiated skin can flare when methotrexate is started or dose escalated
• Sunburn recall - similar phenomenon at prior sunburn sites
• Herpes zoster - modestly increased risk; consider Shingrix vaccine before starting (Section 30)

Skin reactions that need urgent review

• 🔴 Widespread rash with blistering
• 🔴 Rash with mouth or eye involvement (possible Stevens-Johnson syndrome)
• 🔴 Peeling skin over large areas
• 🔴 New pustular eruption
• 🔴 Rash with fever
• 🔴 Non-healing skin ulcer

Skin cancer surveillance on long-term methotrexate

Long-term immunosuppressive therapy modestly raises non-melanoma skin cancer risk. Annual dermatologist check is worthwhile for clients on methotrexate for over 5 years, particularly if fair-skinned or with previous sun damage. Self-checks for new or changing moles. Rigorous sun protection year-round.

Nail changes

• Ridges, colour changes, brittleness can occur
• Usually mild and cosmetic
• Nail health improves with folic acid optimisation
• Paronychia (nail-fold infection) - possible; keep nails clean and dry

The spectrum of liver effects

• 🟢 Transient enzyme elevation (15-30 percent of clients) - usually settles with dose reduction or short break; almost never leads to permanent injury
• 🟡 Persistent enzyme elevation - warrants investigation for other causes (alcohol, fatty liver, viral hepatitis, other drugs)
• 🟡 Hepatic fibrosis - silent progressive scarring, historically linked to cumulative methotrexate doses over 1.5 grams; often accompanies other risk factors
• 🔴 Cirrhosis - rare with modern monitoring; historic risk in psoriasis clients with heavy alcohol use or fatty liver
• 🔴 Acute hepatitis - rare; usually settles with drug cessation

Risk factors for methotrexate liver injury

• Alcohol intake (biggest modifiable risk)
• Obesity and metabolic syndrome
• Diabetes
• Existing fatty liver (MASLD/NAFLD)
• Chronic viral hepatitis B or C
• Other hepatotoxic drugs
• Long duration of therapy and high cumulative dose
• Psoriasis (higher risk than RA at same dose - reasons debated)
• Male sex (modest excess risk)
• Iron overload

Monitoring schedule

• ALT/AST and ALP baseline before starting
• Repeat at 4 weeks after starting or after dose change
• Then every 8-12 weeks when stable
• Also monitor albumin as a marker of synthetic liver function
• Consider baseline liver ultrasound in higher-risk clients
• FibroScan (transient elastography) every 1-2 years in long-term therapy - non-invasive fibrosis assessment
• PIIINP (procollagen III N-terminal propeptide) serial testing in some centres
• Liver biopsy is now rarely performed - reserved for unexplained persistent enzyme elevation or abnormal non-invasive tests

What to do if enzymes are elevated

Warning signs of hepatotoxicity

• 🔴 Yellow skin or eyes (jaundice)
• 🔴 Dark tea-coloured urine
• 🔴 Pale (clay-coloured) stools
• 🔴 Right upper abdominal pain
• 🔴 Persistent severe fatigue
• 🔴 Nausea or vomiting with any of the above
• 🔴 Easy bruising or bleeding (advanced liver disease sign)
• 🔴 Swelling in legs or abdomen (advanced disease sign)

Why methotrexate suppresses bone marrow

Bone marrow contains rapidly dividing precursor cells for red cells, white cells, and platelets. Methotrexate blocks DNA synthesis in these dividing cells. At low weekly doses the effect is usually mild. At higher doses or when methotrexate accumulates (drug interactions, renal impairment, daily-dosing error), suppression can be profound.

What to watch on blood counts

• Neutrophil count - watch for drop below 1.5 x10^9/L; below 1.0 is dangerous
• Platelet count - watch for drop below 100 x10^9/L; below 50 is dangerous
• Haemoglobin - macrocytic anaemia (high MCV) is common and usually reflects folate depletion
• Total white cell count and lymphocyte count also useful

Monitoring schedule

• Baseline full blood count before starting
• Every 2 weeks for first 6 weeks
• Every 4-8 weeks for next 3-6 months
• Every 12 weeks once stable
• Additional bloods after any dose escalation
• Additional bloods during acute illness or new medication
• Section 26 covers the monitoring schedule in more detail

When bloods fall - decision rules

Emergency signs

• 🔴 Fever with neutropenia - medical emergency; broad-spectrum antibiotics within an hour
• 🔴 Unusual bruising or petechiae - possible severe thrombocytopenia; urgent bloods
• 🔴 Bleeding from gums or nose beyond usual
• 🔴 Blood in urine, stool, or vomit
• 🔴 Severe unexplained fatigue with breathlessness (anaemia signal)

Situations that trigger sudden myelosuppression

• Daily dosing error (Section 8)
• Concurrent trimethoprim or trimethoprim-sulfamethoxazole (Section 22)
• Concurrent high-dose NSAIDs, particularly in renal impairment (Section 23)
• Acute kidney injury (dehydration, sepsis, contrast) causing methotrexate accumulation
• New probenecid or other renal transport inhibitor
• Older client whose renal function has drifted downward without dose adjustment

What methotrexate pneumonitis looks like

• Progressive dry cough - the most common early feature
• Shortness of breath at rest or on minimal exertion
• Fever - low-grade to moderate
• Fatigue and general malaise
• Chest X-ray - bilateral interstitial infiltrates
• Reduced oxygen saturation on pulse oximetry
• Can occur at any time in therapy - weeks or years after starting
• Not dose-dependent - can happen at any dose level

Any new persistent respiratory symptom on methotrexate is a red flag

Do not attribute a new dry cough or breathlessness to a cold. Contact the treating team. Chest X-ray and oxygen saturation are the first-line assessment. Methotrexate should be held until the cause is clarified.

Risk factors

• Pre-existing lung disease
• Rheumatoid arthritis (RA lung disease and MTX pneumonitis overlap - hard to distinguish)
• Diabetes
• Older age
• Hypoalbuminaemia
• Prior use of DMARDs
• Recent lung infection

Diagnosis and management

• Immediate cessation of methotrexate
• Chest X-ray and high-resolution CT of the thorax
• Exclude infection (blood cultures, sputum, viral swabs, sometimes bronchoscopy)
• Corticosteroids often used for confirmed pneumonitis
• Supplemental oxygen if hypoxic
• ICU care if respiratory failure develops
• Rheumatology and respiratory input needed

Do not restart methotrexate after confirmed pneumonitis

Rechallenge carries a high recurrence rate with worse severity. Alternative DMARDs or biologics should be substituted. Discuss with rheumatology before considering any exception.

Distinguishing pneumonitis from other lung problems

The differential includes: pneumonia (bacterial, PJP, viral, fungal), tuberculosis reactivation, rheumatoid lung disease progression, pulmonary embolism, heart failure. This is why chest imaging and often bronchoscopy are needed - the diagnosis affects both immediate treatment and long-term decisions about methotrexate.

Methotrexate clearance basics

• Over 80 percent renally excreted unchanged
• Half-life extends dramatically in renal impairment
• Actively secreted by kidney tubules via specific transporters
• Drugs that compete for or block those transporters increase methotrexate levels (Section 22)
• Acidic urine reduces methotrexate solubility - contributes to crystal formation at high doses

Dose adjustment for eGFR

Monitoring renal function

• Serum creatinine and calculated eGFR before starting
• Every 8-12 weeks with routine bloods
• More often in older clients or those with borderline function
• Cystatin C sometimes preferred over creatinine in older or lower-muscle-mass clients
• After any acute illness or new medication with renal risk

Dangerous scenarios

• 🔴 Acute kidney injury on a stable methotrexate dose - dehydration, sepsis, contrast, new nephrotoxin
• 🔴 Older client whose eGFR has drifted down without dose adjustment
• 🔴 Adding NSAIDs in a client with borderline renal function
• 🔴 Contrast imaging in a methotrexate client with limited renal reserve
• 🔴 Recent gastroenteritis causing volume depletion
• 🔴 New ACE inhibitor or ARB reducing glomerular filtration

Practical rules

• Hold methotrexate during acute illness with dehydration until recovery
• Hold methotrexate around contrast imaging (24 hours before, 48 hours after)
• Ensure hydration during hot weather, exercise, travel
• Review all new prescriptions for renal or interaction risk
• Report to treating team any new NSAID use

Combinations to avoid or use only with specialist input

• 🔴 Trimethoprim and trimethoprim-sulfamethoxazole (co-trimoxazole) - additive antifolate effect; can cause severe myelosuppression; avoid combination or hold methotrexate
• 🔴 Nitrous oxide (dental or surgical anaesthesia) - inactivates methionine synthase and worsens antifolate effect; avoid on methotrexate day and for 24 hours after
• 🔴 Probenecid - blocks methotrexate renal secretion; dangerous rise in methotrexate levels
• 🔴 Penicillins (high dose) - compete for renal tubular secretion; monitor closely
• 🔴 Ciprofloxacin (high dose) - reduces methotrexate clearance
• 🔴 Sulfonamides - both antifolate action and renal displacement
• 🔴 Doxycycline - reduces methotrexate clearance
• 🔴 Live vaccines - contraindicated (Section 30)

Common interactions worth flagging

• 🟡 NSAIDs - see Section 23 for detailed rules
• 🟡 Aspirin (high dose) - similar to NSAIDs; low-dose 75 mg aspirin usually safe
• 🟡 Proton pump inhibitors (omeprazole, esomeprazole) - can raise methotrexate levels particularly at high doses; usually fine at low weekly rheumatology doses
• 🟡 Ciclosporin - increases methotrexate levels; combined use in RA needs closer monitoring
• 🟡 Leflunomide - combined use is possible but liver toxicity risk is additive; needs monitoring
• 🟡 Retinoids (acitretin, isotretinoin) - additive liver toxicity in psoriasis; specialist decision
• 🟡 Live vaccines - avoid throughout methotrexate therapy

Combinations that are usually fine

• 🟢 Paracetamol (acetaminophen) at usual doses
• 🟢 Low-dose aspirin (75 mg for cardiovascular protection)
• 🟢 Most antihypertensives (except monitor when starting or dose-escalating ACE inhibitors, ARBs)
• 🟢 Statins
• 🟢 Metformin
• 🟢 Antihistamines
• 🟢 Prednisolone (commonly co-prescribed in RA)
• 🟢 Hydroxychloroquine (commonly combined)
• 🟢 Sulfasalazine (commonly combined - triple DMARD therapy)
• 🟢 Biologics (TNF inhibitors, etc.) - designed to combine with methotrexate
• 🟢 JAK inhibitors (tofacitinib, baricitinib, upadacitinib) - commonly combined

Rules to work by

• Tell every doctor and pharmacist you take methotrexate
• Check every new prescription with the pharmacist for methotrexate interactions
• Never take antibiotics without disclosing your methotrexate use
• Check over-the-counter cold and flu remedies (some contain aspirin or NSAIDs)
• Herbal supplements: liver-active herbs (kava, comfrey, high-dose green tea extract) worth avoiding
• Report any new medication to your rheumatologist at the next visit

The interaction in detail

NSAIDs compete with methotrexate for renal tubular secretion, which can raise methotrexate levels. NSAIDs also reduce renal blood flow (via prostaglandin inhibition), which further reduces methotrexate clearance. In clients with normal renal function on low weekly methotrexate doses, the interaction is usually clinically insignificant. In clients with reduced renal function, dehydration, or high-dose methotrexate, the interaction can produce dangerous accumulation.

Practical rules

Practical alternatives to NSAIDs

• Paracetamol (acetaminophen) - first-line for pain in methotrexate clients where NSAIDs are best avoided
• Topical NSAIDs (diclofenac gel) - minimal systemic absorption; safe alongside methotrexate
• Capsaicin cream for localised joint pain
• Heat and cold therapy
• Physical therapy
• If your rheumatoid arthritis is causing pain requiring regular NSAIDs, disease control may need optimisation - discuss with your rheumatologist

Check over-the-counter products carefully

• 🔴 Many cold and flu remedies contain ibuprofen or aspirin
• 🔴 Combination pain products often contain NSAIDs
• 🔴 Sports pain gels can be topical NSAIDs (usually fine) or contain other actives
• 🔴 Ask the pharmacist before buying any OTC pain or cold medicine

Sun-related effects on methotrexate

• Increased sunburn tendency - lower threshold for burning; the burn is faster and deeper
• Photosensitivity rash - itchy or scaly rash on sun-exposed areas
• Sunburn recall - previously sunburned skin can flare when methotrexate is started or dose escalated
• Radiation recall - previously irradiated skin can flare on methotrexate
• Increased non-melanoma skin cancer risk in long-term therapy
• Possibly increased melanoma risk - data conflicting; low concern at low weekly doses

Practical sun protection rules

• 🟢 Broad-spectrum sunscreen SPF 50 or higher daily on exposed skin
• 🟢 Reapply every 2 hours, more often when swimming or sweating
• 🟢 Broad-brimmed hat and UV-blocking sunglasses
• 🟢 UV-protective clothing (UPF 30+ or long sleeves/trousers of tight weave)
• 🟢 Seek shade between 11 AM and 3 PM
• 🟢 Extra care at high altitude and near water/snow/sand (UV reflection)
• 🟢 Do not use tanning beds
• 🟢 Extra care during and immediately after the weekly dose day

Skin surveillance

• Monthly self-check of skin - watch for new or changing moles, sores that do not heal, new scaly patches
• Annual dermatology check for anyone on methotrexate over 5 years, particularly fair-skinned or with prior sun damage
• Immediate review for any suspicious lesion
• Baseline photography helpful for comparison over time

Travel and holiday advice

• Do not stop methotrexate for holidays without discussing
• Pack sunscreen SPF 50+ - not always easy to buy abroad
• Consider taking methotrexate a day earlier so the peak photosensitivity is not during peak beach hours
• Time-zone changes - shift methotrexate day gradually if needed
• Vaccination review before travel (Section 30)

The core rule for weekly low-dose methotrexate

• Same day, remembered within a few hours: take it as soon as you remember
• Next morning, less than 24 hours late: take it and continue with usual weekly day next week
• 2-3 days late: take it, but be aware the next dose should still be on the usual weekly day - so the gap will be shortened; alternatively skip and resume next scheduled dose
• More than 3-4 days late: skip the missed dose and take the next dose at usual time
• Never double up
• Never take two doses within the same week

Longer gaps

• Missed 2 consecutive weeks: restart at usual dose; contact treating team if any concern
• Missed 3-4 weeks: discuss with treating team before restart; disease may have flared
• Missed over a month: call before restarting; may need fresh baseline bloods; disease flare likely
• Deliberately stopped by another doctor for a reason: do not restart without discussion

When missed doses become a pattern

Frequent missed doses signal a bigger issue. Common causes:

• 🔴 Side effects making the drug unpleasant - discuss folic acid optimisation, injectable switch, or dose reduction
• 🔴 Adherence system failure - upgrade to weekly pillbox, phone alarm, family cross-check
• 🔴 Cost - generic methotrexate is cheap in most markets; injection more expensive but still affordable
• 🔴 Disease feels controlled and client thinks it is safe to stop - it usually is not; RA and psoriasis flare within weeks to months of stopping
• 🔴 Ambivalence about long-term therapy - honest conversation with treating team

Practical adherence tools

• Weekly pillbox with 7 slots - only the methotrexate slot has tablets
• Phone alarm labelled clearly "Weekly methotrexate - [DAY]"
• Pair with an existing weekly habit (Sunday breakfast, Friday evening)
• Family member cross-check
• Adherence app with weekly recurrence
• Auto-refill prescription 2 weeks before running out
• Travel pack with extra doses

Standard monitoring schedule

What each test tells you

• Full blood count (FBC) - detects myelosuppression before it becomes dangerous; watch neutrophils and platelets specifically
• Creatinine and eGFR (U&E) - detects renal impairment that could cause methotrexate accumulation
• Liver function tests (LFTs) - ALT/AST for hepatocellular injury; ALP for cholestatic; albumin for synthetic function
• Vitamin D - baseline and periodic; often supplemented
• MCV - macrocytosis is common on methotrexate; usually reflects folate depletion, sometimes B12 deficiency
• Chest X-ray - baseline for pneumonitis reference; repeat if new respiratory symptoms
• FibroScan or PIIINP - long-term liver fibrosis surveillance in dermatology practice

Timing your blood test around the weekly dose

Blood tests are best taken midway between doses - typically 3-4 days after the last methotrexate dose. Testing the morning after methotrexate can show transient dips that do not reflect the average. Consistency matters more than exact timing - always at the same interval.

Do not skip monitoring

Long stable spells make it tempting to skip a monitoring check "just once". The problem is that methotrexate toxicity often presents late once already advanced. Sudden neutropenia or new hepatitis can develop quietly and be picked up only on scheduled bloods. Every skipped check is a missed opportunity. Shared care between rheumatology and primary care should not become an opportunity for slots to fall through the cracks.

Keeping track

• Ask for a copy of your results after each check
• Keep a running list of key values (neutrophils, platelets, ALT, creatinine) over time
• Report worsening trends even before the value crosses a "danger" threshold
• Bring the list to specialist appointments
• Watch for slow drift that shared-care between departments might miss

Juvenile idiopathic arthritis (JIA)

• First-line DMARD in most JIA subtypes after inadequate response to NSAIDs and intra-articular steroid
• Dose 10-15 mg/m2 once weekly, subcutaneous preferred in children (better absorption, less nausea)
• Folic acid supplementation same principles as adults
• Weekly dosing rules absolute - paediatric education must be crystal clear for parents
• Time to effect 6-12 weeks
• Response rates similar to adults
• Combined with biologics (etanercept, adalimumab, tocilizumab) in more severe cases

Acute lymphoblastic leukaemia (ALL)

• Foundational to childhood ALL protocols
• Intrathecal methotrexate for CNS prophylaxis (typically 12 mg per dose)
• High-dose IV methotrexate (1000-5000 mg/m2) during consolidation, with mandatory leucovorin rescue
• Low-dose oral or IM methotrexate weekly during 2-3 year maintenance phase, combined with 6-mercaptopurine
• St. Jude and COG protocols set the international standard
• Cure rates for childhood ALL exceed 90 percent in high-income countries

Practical family guidance for weekly methotrexate

• One day of the week, always - families choose weekends or a memorable evening
• Subcutaneous injection often better tolerated than oral in children - less nausea
• Numbing cream (EMLA) before injection helps young children
• Rotate injection sites (thigh, abdomen, upper arm)
• Reward routines around dose day (favorite meal, movie night)
• Attend all blood test appointments
• Do not stop for common childhood illness without discussion
• Report fever, mouth ulcers, unusual bruising, new respiratory symptoms promptly
• Sun protection important; regular skin checks
• Live vaccines contraindicated - review immunisation history before starting
• School and nursery informed of the diagnosis and medication

Long-term considerations for children on methotrexate

• Growth monitoring - most children on methotrexate grow normally
• Vaccination catch-up before starting, then no live vaccines during therapy
• Fertility - low-dose weekly methotrexate does not appear to affect long-term fertility in either sex
• Transition to adult rheumatology - structured handover matters
• Contraception discussion in adolescence - teratogenic drug requires reliable contraception
• Alcohol education as teens - stricter rules than peers

What changes with age

• Renal function declines with age - even normal creatinine can hide a fallen eGFR
• Baseline haematological reserve lower - cytopenia more consequential
• Polypharmacy interactions rise - each new medication is a fresh risk
• Cognitive change affects adherence - weekly rule easier to confuse with daily medications
• Fall risk higher if fatigue increases
• Skin fragility increases
• Skin cancer surveillance more important
• Infection risk higher both from age and disease

Practical adjustments

• Lower starting dose - 7.5-10 mg weekly rather than 15 mg
• Renal function-based dose adjustment - reduce for eGFR under 60
• More frequent blood count monitoring, especially during titration
• Careful review of concurrent medications - NSAIDs, trimethoprim, ACE inhibitors deserve extra attention
• Family or caregiver involvement in weekly dosing rule
• Weekly pillbox particularly important
• Consider subcutaneous injection for reliable absorption
• Vaccination review including pneumococcal, flu, shingles (Shingrix), COVID-19
• Regular dermatology review for skin cancer surveillance
• Bone health - dual energy X-ray absorptiometry (DXA), calcium and vitamin D

Frailty over age

Age alone is a poor guide to what clients tolerate. A fit 78-year-old with rheumatoid arthritis can continue methotrexate indefinitely with good response. A frail 68-year-old with multiple comorbidities may struggle with monitoring demands or drug interactions. Individual assessment - looking at functional status, cognitive capacity, comorbidities, polypharmacy, social support - guides the plan better than age alone.

Older adults are more vulnerable to daily-dosing errors

The tragic case series of methotrexate deaths from daily-dosing error concentrates in older clients - polypharmacy, cognitive slippage, and cascading care handovers all raise risk. Family and caregivers must know the weekly rule. Community pharmacy dosing systems (weekly blister packs) should mark methotrexate visibly.

Routine sick day rules

Neutropenic fever is an emergency

If your most recent blood count showed low neutrophils and you develop fever above 38 C, this is a medical emergency. Contact the treating team immediately or attend emergency department. Broad-spectrum antibiotics within an hour are essential. Do not wait to see if it settles.

Specific infection concerns on methotrexate

• Herpes zoster (shingles) - modestly increased risk; consider Shingrix vaccine before starting
• Reactivation of latent tuberculosis - screen before starting long-term methotrexate
• Hepatitis B reactivation - screen for prior infection; consider prophylaxis if HBsAg or anti-HBc positive
• Pneumocystis jirovecii pneumonia - uncommon on methotrexate alone; more concern in combination immunosuppression
• Bacterial pneumonia - somewhat increased risk; pneumococcal vaccination important
• Cellulitis - clients with RA joint deformities and skin fragility at higher risk

The trimethoprim trap

Trimethoprim (alone or as trimethoprim-sulfamethoxazole/co-trimoxazole) is a common antibiotic for urinary tract infections and other uses. It shares the antifolate mechanism with methotrexate. Combined use causes severe additive bone marrow suppression and has caused deaths. Any prescriber writing an antibiotic for a client on methotrexate must be told - alternative antibiotics exist for essentially every indication where trimethoprim would be used.

Hospital admission

• Tell the admitting team you are on methotrexate
• Blood counts on admission if not recent
• Do not accept trimethoprim without discussion
• Do not accept NSAIDs in acute kidney injury without discussion
• Ensure the discharge summary specifies weekly methotrexate dose and folic acid regimen
• Any missed dose during admission - clarify the plan for restart before leaving

Live vaccines - avoid

• 🔴 MMR (measles, mumps, rubella)
• 🔴 Varicella (chickenpox)
• 🔴 Live zoster (Zostavax - largely replaced by inactivated Shingrix)
• 🔴 Yellow fever
• 🔴 BCG
• 🔴 Oral polio
• 🔴 Live nasal flu (use injectable inactivated flu instead)
• 🔴 Rotavirus in infants
• 🔴 Oral typhoid (Ty21a)

Inactivated vaccines - safe and important

• 🟢 Annual flu vaccine (inactivated injection) - strongly recommended
• 🟢 Pneumococcal (PCV13/PCV15/PCV20 and PPV23) - strongly recommended
• 🟢 COVID-19 vaccines
• 🟢 Shingrix (recombinant zoster) - safe and strongly recommended, particularly in older methotrexate clients
• 🟢 Hepatitis B (if not already immune)
• 🟢 Meningococcal ACWY and B where indicated
• 🟢 HPV in appropriate age groups
• 🟢 Tdap (tetanus, diphtheria, pertussis)
• 🟢 Injectable typhoid for travel
• 🟢 Rabies (pre-exposure or post-exposure)
• 🟢 Hepatitis A for travel
• 🟢 Japanese encephalitis (inactivated)

Timing before starting methotrexate

Where possible, complete vaccination catch-up before starting methotrexate. This is particularly important for live vaccines that will be off-limits later. Delay methotrexate initiation by 2-4 weeks after a live vaccine where clinically reasonable. Adult MMR, varicella, and inactivated Shingrix are the main considerations. Zostavax is now largely replaced by inactivated Shingrix which is preferred and safe throughout methotrexate therapy.

Vaccine response on methotrexate

Antibody response to vaccines is somewhat reduced on methotrexate. For most vaccines the response is still clinically useful. For flu vaccine, some rheumatology guidelines suggest holding methotrexate for 2 weeks after vaccination to improve response - discuss with your treating team. Two-dose schedules (Shingrix, hepatitis B) may need attention to ensure both doses are given.

Household contacts

Household contacts of methotrexate clients can receive most live vaccines without special precaution. The main exception is oral polio (avoided in developed countries anyway). Rotavirus-vaccinated infants should have careful nappy hygiene by immunosuppressed household members for 4 weeks. Chickenpox-vaccinated children rarely shed enough virus to matter but any rash after vaccination should be covered.

Fetal risks of methotrexate exposure

• Aminopterin/methotrexate embryopathy - characteristic pattern of craniofacial defects, limb anomalies, growth restriction
• Miscarriage rate substantially increased
• Structural malformations - CNS defects, cardiac defects, limb reduction, cleft palate
• Fetal growth restriction
• Third trimester exposure - bone marrow suppression in newborn, possible haematological toxicity
• Methotrexate is used deliberately to terminate ectopic pregnancy - this alone tells you it kills trophoblast reliably

Contraception rules

Planning pregnancy on methotrexate

1. Discuss pregnancy plans at least 6 months in advance with rheumatologist
2. Stop methotrexate at least 3-6 months before attempting conception (guidelines vary; discuss individually)
3. Fold in folic acid supplementation at pre-pregnancy dose (400 micrograms daily minimum)
4. Switch to pregnancy-compatible DMARD if disease control needed - sulfasalazine, hydroxychloroquine, azathioprine, certolizumab (biologic), and some other TNF inhibitors are options
5. Multidisciplinary care - rheumatology, obstetrics, sometimes maternal-fetal medicine
6. Do not restart methotrexate until breastfeeding is complete

If pregnancy is confirmed while on methotrexate

1. Stop methotrexate immediately
2. Start high-dose folic acid 5 mg daily
3. Contact rheumatology and obstetrics urgently
4. Referral to maternal-fetal medicine specialist for counselling
5. Detailed fetal imaging - anatomic scan and echocardiography
6. Options discussion - continuation with monitoring versus termination based on gestational age and individual circumstances
7. Alternative disease control for pregnancy - pregnancy-compatible DMARDs and biologics available

The paternal question

Historic concerns about paternal methotrexate exposure causing birth defects have been largely reassured by recent large registry studies showing no clear excess of malformations in babies fathered by men taking low-dose methotrexate. Current EULAR guidance no longer mandates paternal contraception, though counselling is still advised. Individual discussion with the treating team helps navigate the evolving evidence.

Absolute contraindications

• Pregnancy - teratogenic and abortifacient
• Breastfeeding - drug transfers into milk
• Known hypersensitivity to methotrexate
• Severe hepatic impairment - Child-Pugh B or C cirrhosis, active hepatitis
• Severe renal impairment - eGFR under 30
• Bone marrow failure or severe cytopenia at baseline
• Active serious infection - stabilise first
• Active peptic ulcer disease
• Immunodeficiency syndromes
• Alcohol dependence unable to abstain

Relative contraindications - use with caution and specialist input

• Chronic hepatitis B or C
• Moderate renal impairment (eGFR 30-60) - reduce dose, monitor closely
• Fatty liver disease (MASLD/NAFLD)
• Existing chronic lung disease with reduced pulmonary reserve
• Poor adherence potential - cognitive impairment without adequate support
• Prior severe drug-induced pneumonitis or hepatotoxicity from other drugs
• Non-healing skin ulcer
• Prior secondary malignancy from cytotoxic exposure (relative)
• Inability to attend for monitoring

Reasons to stop methotrexate permanently once started

• Methotrexate pneumonitis (do not rechallenge)
• Severe cytopenia unresponsive to dose reduction
• Persistent liver enzyme elevation despite dose reduction
• Established hepatic fibrosis or cirrhosis
• Non-healing methotrexate-associated skin ulcer
• Development of lymphoproliferative disorder
• Pregnancy planning
• Development of malignancy where methotrexate is contraindicated
• Persistent severe intolerance despite optimisation

Do not stop methotrexate on your own without discussion

Rheumatoid arthritis and psoriasis flare within weeks of stopping methotrexate. Silent discontinuation - without an alternative in place - leads to disease flare, joint damage, worse outcomes, and often the need for higher-dose therapy later. Almost every reason to consider stopping methotrexate has an alternative that keeps the underlying disease controlled. Always discuss before stopping.

Breastfeeding - not compatible with methotrexate

• 🔴 Methotrexate transfers into breast milk
• 🔴 Bone marrow suppression risk to infant
• 🔴 Complete breastfeeding before restarting methotrexate, or formula-feed if methotrexate cannot be delayed
• 🔴 Discuss postnatal disease control plan before delivery
• 🔴 Pregnancy-compatible DMARDs and biologics can bridge the postnatal breastfeeding period

Storage

• Room temperature under 25 C in original packaging
• Protect from light and moisture
• Not in bathroom (humidity)
• Not in hot car
• Out of reach of children and pets - cytotoxic
• Weekly pillbox stores away from daily medications
• Subcutaneous pens - room temperature; do not freeze
• Do not use past expiry
• Return unused tablets or pens to pharmacy for cytotoxic waste disposal

Travel

• Pack in hand luggage - not checked
• Take 30 percent extra supply
• Original packaging with pharmacy label for customs
• Travel letter from treating team for long trips or overseas travel
• Time zones - shift methotrexate day gradually if crossing over 4 hours
• Sun protection critical in hot climates (Section 24)
• Vaccinations - no live vaccines; discuss destination with treating team
• Insect-bite prevention if travelling to malaria area (methotrexate does not exclude malaria prophylaxis - most options are compatible)
• Travel insurance - declare RA/psoriasis/other condition and methotrexate
• Injection pens - portable cooler bag for long journeys

Surgery on methotrexate

• Tell every surgeon and anaesthetist
• Blood count check before elective surgery
• Most elective surgery can proceed on methotrexate - infection and wound healing data reassuring
• Some centres hold methotrexate 1-2 weeks around major surgery, particularly joint replacement
• Guidelines vary - discuss with rheumatology and surgery
• Avoid nitrous oxide anaesthesia on the methotrexate day and for 24 hours after (severe additive antifolate effect)
• Watch for AKI perioperatively - dose adjustment or hold if kidney function drops

Yearly review checklist

• Full blood count
• Renal function (creatinine, eGFR)
• Liver function tests including albumin
• Vitamin D and calcium
• Disease activity score (DAS28 in RA, PASI in psoriasis)
• Skin surveillance - full-body check
• Cardiovascular risk assessment (BP, lipids, glucose) - RA carries excess CV risk
• Bone density (DXA) - consider particularly if on concurrent steroids
• Vaccination status (flu, pneumococcal, Shingrix, COVID)
• Contraception discussion in reproductive-age women
• Alcohol intake honest conversation
• Liver imaging or FibroScan every 1-2 years in long-term therapy
• Chest X-ray if new respiratory symptoms since last review
• Medication reconciliation - flag interactions
• Discussion of whether to continue, adjust dose, or consider taper if disease in sustained remission

A closing thought

Methotrexate is one of medicine's most quietly consequential drugs. It transformed childhood leukaemia from fatal to curable in the 1950s. It transformed rheumatoid arthritis from progressively disabling to controllable in the 1980s. It has kept ectopic pregnancies from becoming surgical emergencies. It sits on the WHO Essential Medicines List and remains affordable worldwide. Taken faithfully with weekly dosing discipline, folic acid supplementation, and regular blood monitoring, it delivers meaningful benefit over years or decades. The rules matter - weekly not daily, contraception when relevant, alcohol moderation, prompt attention to warning signs - but within those rules methotrexate is safe, effective, and inexpensive. Few drugs justify quite so much loyalty from the specialties that use them.