Pain Medications - NSAIDs, COX-2 Inhibitors, Topical Analgesics
Pain affects nearly everyone at some point, ranging from acute injury and post-operative recovery to chronic conditions that persist for months or years. The WHO estimates that 20% of adults worldwide experience persistent pain, making it one of the most common reasons for medical visits and a leading cause of disability. Modern pain pharmacotherapy uses a step-wise approach — matching drug class to pain intensity, mechanism (nociceptive vs. neuropathic vs. inflammatory), duration, and patient-specific factors including age, kidney/liver function, and comorbidities.
This catalogue focuses primarily on non-opioid analgesics: paracetamol (acetaminophen), oral NSAIDs (ibuprofen / Motrin, naproxen / Naprosyn, diclofenac / Voltaren, meloxicam / Mobic, piroxicam / Feldene, indomethacin / Indocin, mefenamic acid / Ponstel, celecoxib / Celebrex / Celeheal), topical NSAIDs (Voltaren Gel, Emulgel, Diclofenac Gel), and selected specialty agents like oral corticosteroids (Deltasone / prednisone) and danazol (Danocrine). Opioid analgesics are not stocked through this catalogue because of regulatory requirements; chronic pain often involves multimodal therapy combining analgesics, physical therapy, behavioural strategies, and sometimes interventional procedures.
Choosing the right pain medication depends on pain intensity, duration, mechanism, and patient factors. Mild-to-moderate acute musculoskeletal pain typically responds well to paracetamol or NSAIDs; chronic pain may benefit from adjuvant medications (antidepressants, anticonvulsants) typically found in other categories. The "weak-then-strong" WHO pain ladder, originally developed for cancer pain, broadly guides modern outpatient pain management.
🥕 Conditions This Category Treats
Acute musculoskeletal pain from sprains, strains, contusions, and post-exercise soreness typically responds well to topical NSAIDs (Voltaren Gel, Emulgel, Diclofenac Gel) for localised problems and oral NSAIDs (ibuprofen, naproxen, diclofenac) for more widespread or severe acute pain. Acute headache (tension-type, mild migraine) usually responds to paracetamol, ibuprofen, naproxen, or a triptan if specifically migraine; chronic headache requires investigation. Dental pain responds particularly well to NSAIDs because of the inflammatory component; ibuprofen 400-600 mg + paracetamol 1000 mg combination is highly effective.
Osteoarthritis pain — the most common form of chronic pain — benefits from topical NSAIDs first-line for hand and knee, oral NSAIDs (Mobic / meloxicam, Celebrex / celecoxib) for more widespread or severe disease, and consideration of intra-articular corticosteroid or hyaluronic acid injections. Rheumatoid arthritis and other inflammatory arthritis use NSAIDs alongside DMARDs and biologics covered in Arthritis category. Acute gout responds well to indomethacin (Indocin), naproxen, or colchicine; chronic gout prevention uses allopurinol from the Arthritis category.
Dysmenorrhoea (painful periods) responds well to mefenamic acid (Ponstel) — the most prostaglandin-specific NSAID — started 1-2 days before menses and continued through the first 2-3 days of bleeding. Endometriosis-associated pain may benefit from danazol (Danocrine), a synthetic androgen that suppresses ovarian function and reduces ectopic endometrial tissue activity — though hormonal contraceptives and modern GnRH analogues are usually preferred first-line. Severe acute inflammatory pain from polymyalgia rheumatica, giant cell arteritis, severe gout, or autoimmune flares may briefly require oral corticosteroids like prednisone (Deltasone). Chronic stable angina uses isosorbide mononitrate (Imdur) for prevention — though strictly cardiovascular, it appears in this catalogue for historical category reasons.
💊 How Modern Pain Treatment Works
Paracetamol (acetaminophen) remains incompletely understood mechanistically but appears to act via central COX-3 inhibition and modulation of descending serotonergic pain pathways. It is an effective analgesic and antipyretic but has minimal anti-inflammatory effect. Maximum safe daily dose is 3-4 g in healthy adults; doses above 7-10 g (or chronic use of 4 g daily in vulnerable individuals) cause severe hepatotoxicity. N-acetylcysteine is the antidote if overdose is suspected. Reduce maximum dose in elderly, regular alcohol users, malnourished, or those with liver disease.
Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit cyclooxygenase enzymes (COX-1 and COX-2) that produce prostaglandins involved in pain, fever, and inflammation. Non-selective NSAIDs (ibuprofen, naproxen, diclofenac, indomethacin, piroxicam, mefenamic acid) block both isoforms and cause typical NSAID side effects: GI ulcers and bleeding (COX-1 mediated), kidney impairment, hypertension, fluid retention, and small increases in cardiovascular events. COX-2 selective inhibitors (Celebrex / celecoxib) spare COX-1 in the GI tract, reducing ulcer risk by approximately 50%, at slight increase in cardiovascular events compared to non-selective NSAIDs. Topical NSAIDs (Voltaren Gel, Emulgel) achieve high local skin and synovial concentrations with minimal systemic absorption — preferred for localised hand and knee osteoarthritis with much lower side-effect profile.
Corticosteroids (prednisone / Deltasone) exert broad anti-inflammatory effects via genomic and non-genomic mechanisms. For severe acute inflammatory pain (gout flare, severe back pain with sciatic component, polymyalgia rheumatica), a short course can provide dramatic relief. Danazol (Danocrine) is a synthetic 17-alpha-ethinyltestosterone derivative that suppresses pituitary gonadotropin release, inducing a hypoestrogenic state useful in endometriosis, hereditary angioedema, and fibrocystic breast disease. Side effects (acne, hirsutism, deepening voice, weight gain, mood changes) limit modern use; newer alternatives are usually preferred. Isosorbide mononitrate (Imdur) is a nitrate-based vasodilator for chronic stable angina prevention; preserves the nitrate-free interval pattern to avoid tolerance.
💊 Drug Classes in This Category
| Class | Best For | Examples |
|---|---|---|
| Paracetamol | Mild-moderate pain, fever, first-line in elderly and frail | Paracetamol (acetaminophen) |
| Oral NSAIDs (non-selective) | Inflammatory pain, OA, RA, dental, dysmenorrhea, acute gout | Motrin (ibuprofen), Naprosyn (naproxen), Voltaren (diclofenac), Mobic (meloxicam), Feldene (piroxicam), Indocin (indomethacin), Ponstel (mefenamic acid) |
| COX-2 selective NSAID | OA, RA when GI risk elevated; lower ulcer risk than non-selective | Celebrex (celecoxib), Celeheal (celecoxib) |
| Topical NSAIDs | Localised OA (hand, knee), acute musculoskeletal injury | Voltaren Gel, Emulgel, Diclofenac Gel |
| Oral corticosteroid | Severe acute inflammation, autoimmune flares, polymyalgia | Deltasone (prednisone) |
| Synthetic androgen | Endometriosis, hereditary angioedema, fibrocystic breast | Danocrine (danazol) |
| Nitrate (cardiac) | Chronic stable angina prevention | Imdur (isosorbide mononitrate) |
✅ How to Choose
- 🥕 Mild headache, fever, general pain → Paracetamol 500-1000 mg every 4-6 hours (max 4 g/day; less in vulnerable groups).
- 🦴 Localised hand or knee osteoarthritis → Voltaren Gel or Emulgel applied 3-4 times daily — better safety than oral NSAIDs.
- 🪨 Moderate acute pain (dental, post-op, sports injury) → Motrin (ibuprofen) 400 mg every 6 hours or Naprosyn (naproxen) 500 mg twice daily; combine with paracetamol for additive effect.
- 🪿 Painful periods (primary dysmenorrhea) → Ponstel (mefenamic acid) 500 mg three times daily starting 1-2 days before menses through day 2-3 of bleeding.
- 🪥 Acute gout flare → Indocin (indomethacin) 50 mg three times daily for 2-3 days then taper, OR colchicine (in Arthritis category), OR oral prednisone short course.
- 🪻 High GI risk patient needing NSAID (older, prior ulcer, on anticoagulant) → Celebrex (celecoxib) 200 mg daily with proton pump inhibitor.
- 🌹 Endometriosis pain refractory to first-line → Danocrine (danazol) consideration in selected patients; modern alternatives often preferred.
- 🫀 Chronic stable angina → Imdur (isosorbide mononitrate) — covered in Cardiovascular too.
❓ Frequently Asked Questions about Pain Medications
Should I take paracetamol or ibuprofen for pain?
Both work for mild-moderate pain. Paracetamol has the fewest side effects and is preferred in elderly, on blood thinners, with kidney or stomach issues, in pregnancy. Ibuprofen works better for inflammatory pain (sprains, dental, period pain, arthritis flares) because it reduces inflammation. For severe acute pain, combining paracetamol 1000 mg + ibuprofen 400 mg provides additive relief.
Why is Celebrex better than ibuprofen for some people?
Celebrex (celecoxib) selectively blocks COX-2 (the inflammation enzyme) while sparing COX-1 (which protects the stomach lining). Result: roughly half the GI ulcer risk of non-selective NSAIDs. Better choice for elderly, prior ulcer history, on anticoagulants, or those requiring chronic NSAID use. Slight increase in cardiovascular events compared to non-selective NSAIDs is the trade-off.
Can I use Voltaren Gel for muscle injuries?
Yes — topical NSAIDs work well for localised musculoskeletal pain within several centimetres of the skin (hand, knee, ankle, shoulder OA, sprains). They penetrate skin and reach high concentrations in superficial joints and muscles. Apply to clean dry skin 3-4 times daily; wash hands after. Avoid open wounds. Limited effect on deep joints (hip).
Why do NSAIDs damage the kidneys?
NSAIDs inhibit prostaglandins that maintain kidney blood flow under stress. In healthy young adults, this rarely causes harm. In patients with dehydration, heart failure, pre-existing kidney disease, on ACE inhibitors or diuretics, prostaglandin-dependent kidney perfusion is critical, and NSAIDs can precipitate acute kidney injury. Stay well hydrated, avoid prolonged use, and check kidney function periodically in chronic users.
Can I take NSAIDs in pregnancy?
Avoid all NSAIDs in the third trimester — cause premature closure of ductus arteriosus and renal/oligohydramnios issues. First and second trimesters: use cautiously and briefly only when paracetamol is insufficient; recent data suggests some risk even in early pregnancy. Paracetamol is the analgesic of choice in pregnancy at standard doses.
When should chronic pain be managed by a specialist?
Persistent pain longer than 12 weeks despite appropriate first-line therapy warrants pain medicine specialist input. Particular indications: neuropathic pain (often needs anticonvulsants/antidepressants), fibromyalgia (often multimodal: low-dose tricyclic, gabapentin, exercise, CBT), chronic back pain with radicular symptoms, cancer pain, and complex regional pain syndrome. Multimodal approaches typically outperform single-agent strategies.
🩺 When to See a Healthcare Provider
Seek urgent evaluation for: "red flag" back pain symptoms (bowel/bladder dysfunction, saddle anaesthesia, progressive weakness, severe nocturnal pain, fever, unexplained weight loss, history of cancer or IV drug use), sudden severe chest pain (cardiac evaluation), severe abdominal pain, acute severe headache with neurological symptoms or worst-ever character, signs of GI bleeding on NSAID (black or bloody stool, coffee-ground vomit, severe upper abdominal pain), or signs of paracetamol overdose.
Chronic pain (over 12 weeks) warrants comprehensive evaluation including specific diagnosis, multimodal therapy planning, and consideration of physiotherapy, behavioural therapy, and interventional procedures alongside medication. Always inform every prescriber about your full medication list — many pain medications interact with anticoagulants, lithium, methotrexate, ACE inhibitors, SSRIs, and others.