Nausea and Vomiting FAQ — Common Questions About Antiemetics

Antiemetics are medications that prevent or treat nausea and vomiting. Different classes work through different mechanisms, making some more suited to specific causes.

Available on RXshop.md:

• Zofran (Ondansetron 4mg) - 5-HT3 serotonin antagonist
• Maxolon (Metoclopramide 10mg) - D2 dopamine antagonist and prokinetic
• Compazine (Prochlorperazine 5mg) - Phenothiazine
• Dramamine (Dimenhydrinate 50mg) - Antihistamine

Choosing based on cause:

Chemotherapy-induced nausea:

• Ondansetron (Zofran) - gold standard
• Combined with steroids often
• Highly effective

Post-operative nausea:

• Ondansetron first-line
• Multi-modal approach

Motion sickness:

• Dimenhydrinate (Dramamine)
• Take BEFORE travel
• Not effective once nauseated

Migraine-related nausea:

• Metoclopramide (Maxolon) - also helps migraine
• Prochlorperazine (Compazine)

Vertigo/vestibular disorders:

• Dimenhydrinate
• Prochlorperazine for severe

Diabetic gastroparesis:

• Metoclopramide (Maxolon) - prokinetic action
• Limited to 12 weeks

Pregnancy nausea (mild-moderate):

• Non-drug first (ginger, B6)
• Metoclopramide if needed
• Ondansetron in severe cases

Gastroenteritis:

• Ondansetron prevents dehydration
• Allows oral rehydration

Key factors in medication choice:

• Cause of nausea
• Severity
• Age (elderly special considerations)
• Other medications
• Sedation acceptable?
• Cardiac conditions (QT prolongation with ondansetron)
• Movement disorders (avoid metoclopramide, prochlorperazine)
• Cost considerations

Combined approaches:

• Different mechanisms complement each other
• Multi-modal treatment better for severe cases
• Physician guidance important

Zofran (Ondansetron 4mg) revolutionized nausea treatment when introduced in 1991. It is highly effective without causing sedation.

How ondansetron works:

• Vagal nerve endings in GI tract
• Chemoreceptor trigger zone in brain
• Nucleus tractus solitarius

Best uses:

Chemotherapy-induced nausea (CINV):

• Gold standard
• Given before chemotherapy
• Combined with dexamethasone
• NK1 antagonists added for highly emetogenic
• Prevents 70-80 percent of nausea

Post-operative nausea:

• Given during surgery
• Continues 24-48 hours after
• Reduces incidence 50 percent
• Combined with other agents

Radiation-induced nausea:

• Upper abdomen radiation especially
• Whole body irradiation
• Given before treatment

Severe gastroenteritis:

• Prevents severe dehydration
• Allows oral rehydration
• Children respond well
• Sometimes given IV

Hyperemesis gravidarum (severe pregnancy nausea):

• When other options fail
• Off-label use
• Some studies show slight cardiac risk to fetus (debated)
• Discuss with obstetrician

Migraine-associated severe nausea:

• Alternative option
• Does NOT treat headache itself
• Enables oral migraine medications

Opioid-induced nausea:

• Well-tolerated with opioids
• Does not worsen constipation as much

Dosing:

• Standard adult: 4-8mg every 8 hours
• Chemotherapy prophylaxis: 8-24mg before treatment
• Post-op prevention: 4mg IV
• Available forms: Tablets, dissolving tablets (ODT), oral solution, injection
• ODT dissolves on tongue (useful during vomiting)
• Take with or without food

Advantages:

• Highly effective
• Minimal sedation
• No cognitive impairment
• Fast onset
• Multiple dosing forms
• Safe in most patients
• Approved for children

Common side effects (usually mild):

• Headache (most common)
• Constipation
• Fatigue
• Dizziness
• Dry mouth
• Elevated liver enzymes

When NOT to use:

• Prolonged QT interval history
• Congenital long QT syndrome
• Severe electrolyte imbalances
• Combination with apomorphine
• Known allergy

Maxolon (Metoclopramide 10mg) is a dopamine antagonist with prokinetic properties, addressing both nausea and delayed gastric emptying.

How metoclopramide works:

Primary uses:

Diabetic gastroparesis:

• Primary indication
• Delayed gastric emptying
• Diabetes complication
• Improves nausea and satiety
• Speeds meal absorption

Chemotherapy-induced nausea:

• Especially for delayed nausea (24+ hours after)
• Combined with other agents
• Alternative if ondansetron ineffective

Radiation-induced nausea

Post-operative nausea

Migraine-associated nausea:

• Often preferred for migraine
• Also enhances absorption of oral migraine medications
• May improve migraine itself

GERD with delayed emptying

Hyperemesis gravidarum

Non-ulcer dyspepsia

Dosing:

• Standard: 10mg 3-4 times daily
• Take 30 minutes before meals and at bedtime
• Maximum 12 weeks continuous use
• Available oral, IV, IM
• Reduce dose in kidney impairment

Common side effects:

• Drowsiness
• Restlessness
• Fatigue
• Diarrhea
• Depression
• Menstrual changes
• Breast tenderness (increased prolactin)

Other serious effects:

• Extrapyramidal symptoms (acute dystonic reactions)
• Akathisia (severe restlessness)
• Neuroleptic malignant syndrome (rare)
• Depression, suicidal thoughts
• QT prolongation

Extrapyramidal symptoms:

• Acute muscle spasms
• Tongue protrusion
• Facial grimacing
• Neck twisting
• Requires diphenhydramine or benztropine treatment

Contraindications:

• Gastrointestinal obstruction
• Perforation
• Hemorrhage
• Pheochromocytoma
• Seizure disorders
• Parkinson disease (worsens)
• Concurrent antipsychotics (movement disorder risk)
• Prior tardive dyskinesia

Precautions:

• Elderly (higher tardive dyskinesia risk)
• Diabetes
• Depression
• Hypertension
• Kidney impairment

Signs to seek immediate care:

• Involuntary movements
• Muscle spasms
• Facial grimacing
• Tongue movements
• Severe restlessness
• Fever with rigidity

Alternatives if metoclopramide not suitable:

• Ondansetron (Zofran)
• Prochlorperazine (Compazine)
• Domperidone (not on RXshop but similar mechanism)

Compazine (Prochlorperazine 5mg) is a phenothiazine antiemetic - one of the oldest but still effective options for severe nausea and vomiting.

How prochlorperazine works:

Best uses:

Severe nausea and vomiting:

• When other antiemetics ineffective
• Combined causes of nausea
• Severe symptoms

Migraine-associated nausea:

• Effective for migraine nausea
• Also may help migraine itself
• Combined with pain medications

Vertigo and vestibular disorders:

• Meniere disease
• Vestibular neuritis
• Labyrinthitis
• Alternative to dimenhydrinate

Post-operative nausea

Radiation-induced nausea

Anxiety and psychosis (at higher doses)

Dosing:

• Standard: 5-10mg 3-4 times daily
• Available oral, IV, IM, suppository
• Suppository useful when vomiting
• Maximum 40mg daily typical
• Take with food if oral

Advantages:

• Very effective for severe nausea
• Available in multiple forms including suppository
• Cost-effective
• Well-established medication
• Multiple mechanisms
• Can address anxiety component

Common side effects:

Serious side effects:

Other serious effects:

• Neuroleptic malignant syndrome (rare, life-threatening)
• QT prolongation
• Blood cell changes
• Liver toxicity
• Seizures (rare)

Contraindications:

• Comatose states
• CNS depression severe
• Bone marrow depression
• Blood cell disorders
• Severe liver disease
• Parkinson disease
• Concurrent large amounts of CNS depressants

Precautions:

• Elderly (increased side effect risk)
• Not for children under 2
• Caution with cardiac conditions
• Avoid with alcohol
• Watch for movement disorders
• Sun protection (photosensitivity)

Age considerations:

Elderly:

• Higher extrapyramidal risk
• Tardive dyskinesia more common
• Falls risk from sedation
• Consider alternatives
• Ondansetron often preferred

Children:

• Not for under age 2
• Higher extrapyramidal risk
• Weight-based dosing
• Alternative usually preferred

Signs of dystonic reaction:

• Sudden muscle contractions
• Neck twisted to one side
• Eyes rolling back
• Tongue protrusion
• Facial grimacing
• Anxiety and distress
• Requires emergency treatment
• Diphenhydramine IV effective

Alcohol and other sedatives:

• Additive CNS depression
• Extreme sedation possible
• Respiratory depression risk
• Avoid combination

Comparing to alternatives:

• vs Ondansetron: cheaper but more sedation and movement risk
• vs Metoclopramide: similar movement risks
• vs Dimenhydrinate: more effective for severe nausea

Dramamine (Dimenhydrinate 50mg) is the go-to medication for motion sickness prevention and vertigo treatment.

How dimenhydrinate works:

Why motion sickness happens:

• Inner ear detects motion
• Eyes see different motion
• Brain receives conflicting signals
• Confusion triggers nausea
• Some people more susceptible genetically

Prevention rules for motion sickness:

Best positions in vehicles:

Car:

• Front seat
• Look at road ahead
• Avoid back seat

Boat:

• Midship (least motion)
• Upper deck
• Fresh air
• Look at horizon

Plane:

• Over the wings
• Air vents open
• Cool temperature

Train:

• Face forward
• Middle of car

Uses beyond motion sickness:

• Vertigo (dizziness)
• Meniere disease
• Vestibular neuritis
• Post-cochlear surgery
• Some pregnancy nausea
• Chemotherapy adjunct

Dosing:

• Adults: 50-100mg every 4-6 hours as needed
• Maximum 400mg per day
• Children 2-6 years: 12.5-25mg every 6-8 hours
• Children 6-12 years: 25-50mg every 6-8 hours
• Take with water or food

Side effects:

Precautions:

• Do NOT drive after taking
• Do NOT operate machinery
• Avoid alcohol
• Prostate enlargement caution
• Glaucoma caution (narrow-angle)
• Asthma caution
• Elderly at higher risk of falls/confusion
• Not recommended under age 2

Anticholinergic warnings:

• Additive with other anticholinergics
• Antihistamines
• Tricyclic antidepressants
• Some antipsychotics
• Muscle relaxants
• MAO inhibitors

Special populations:

Pregnancy:

• Category B
• Generally considered safe
• Discuss with obstetrician
• May help pregnancy nausea
• Some studies show benefit

Children:

• Age 2+ can use
• Weight-based dosing
• Watch for paradoxical excitement
• Behavioral techniques important too

Elderly:

• Higher confusion risk
• Falls risk
• Anticholinergic burden concern
• Consider lower dose
• May be inappropriate (Beers Criteria)
• Meclizine sometimes better tolerated

Alternative motion sickness options:

• Scopolamine patch - long-lasting (3 days)
• Meclizine - similar mechanism, less sedating
• Promethazine - phenothiazine, more sedating
• Ginger - natural approach
• Sea-Bands (acupressure)

Non-medication approaches:

• Acupressure P6 point (Sea-Bands)
• Deep breathing
• Focus on horizon
• Avoid reading
• Small snacks (crackers)
• Ginger tea or candies
• Cool wet cloth on forehead
• Fresh air

When motion sickness pills won't help:

• Already extensive nausea
• Vestibular disorders (require different treatment)
• Non-motion causes of nausea
• Very sensitive individuals may need combinations

Chemotherapy-induced nausea and vomiting (CINV) affects up to 70 percent of patients without prophylaxis. Modern treatment can prevent most cases.

Types of CINV:

Acute:

• Within 24 hours of chemotherapy
• Serotonin-mediated primarily

Delayed:

• 24 hours to 7 days after
• Substance P (NK1) mediated

Anticipatory:

• Before treatment begins
• Psychological/learned response

Breakthrough:

• Despite prophylaxis
• Requires rescue medication

Chemotherapy emetogenic potential:

Highly emetogenic (over 90 percent risk):

• Cisplatin
• Carmustine
• Cyclophosphamide (high dose)
• Dacarbazine

Moderately emetogenic:

• Carboplatin
• Doxorubicin
• Ifosfamide
• Oxaliplatin

Low emetogenic:

• Docetaxel
• Paclitaxel
• Fluorouracil
• Gemcitabine

Treatment approach:

For highly emetogenic:

• 5-HT3 antagonist (ondansetron)
• NK1 antagonist (aprepitant)
• Dexamethasone (steroid)
• Sometimes olanzapine
• Four-drug regimen

For moderately emetogenic:

• 5-HT3 antagonist
• Dexamethasone
• Sometimes NK1 antagonist

For low emetogenic:

• Dexamethasone alone
• Or 5-HT3 antagonist
• PRN antiemetic

Role of Zofran (Ondansetron):

• Foundation of most CINV prevention
• Given before chemotherapy
• Repeated during treatment
• Highly effective for acute phase
• Less effective for delayed nausea
• Combined with other agents

Role of Maxolon (Metoclopramide):

• Useful for delayed nausea
• Alternative if ondansetron ineffective
• Prokinetic effect helpful
• Combined with other agents

Timing of medications:

Pre-chemotherapy (30-60 min before):

• Ondansetron 8-24mg
• Dexamethasone 12mg
• Aprepitant (NK1) if applicable

Day 1:

• Continue prophylaxis
• Rescue meds available

Days 2-5 (delayed nausea):

• Continued ondansetron
• Metoclopramide
• Dexamethasone tapering
• NK1 antagonist

Beyond day 5:

• Late onset possible
• Rescue medications
• Address triggers

Managing breakthrough nausea:

• Different class than prophylaxis
• Prochlorperazine effective
• Ondansetron rescue dose
• Metoclopramide
• Olanzapine
• Lorazepam for anticipatory

Anticipatory nausea:

• Psychological component
• Occurs before treatment
• Difficult to prevent once established
• Lorazepam helpful
• Behavioral techniques
• Relaxation training
• Best prevention: prevent all initial nausea

Non-drug approaches:

• Small frequent meals
• Cool bland foods
• Avoid strong smells
• Ginger
• Acupressure
• Distraction
• Relaxation techniques

Warning signs during chemo:

• Cannot keep fluids down 24+ hours
• Signs of dehydration
• Vomiting blood
• Severe abdominal pain
• Fever
• Contact oncology team

Radiation-induced nausea:

• Similar approach
• Depends on radiation site
• Upper abdomen highest risk
• Whole body irradiation severe
• Ondansetron primary agent

Preventive dosing schedule (chemotherapy):

• Day 0 (before treatment): Full prophylaxis
• Day 1: Continue if inpatient
• Days 2-3: Especially delayed prevention
• Day 4-5: Watch for late nausea
• Individualized approach

Nausea and vomiting affect 50-80 percent of pregnant women, typically improving after week 12-14. Non-medication approaches preferred first, but severe cases may need medications.

Types of pregnancy nausea:

Morning sickness:

• Mild to moderate
• First trimester mostly
• Improves after week 12-14
• Non-drug approaches usually sufficient

Hyperemesis gravidarum:

• Severe (1-2 percent of pregnancies)
• Cannot keep down food/fluids
• Weight loss over 5 percent
• Dehydration
• Electrolyte imbalances
• May require hospitalization
• Requires medications

Non-medication first (always try):

• Small frequent meals
• Bland foods (crackers before rising)
• Ginger (proven anti-nausea)
• Vitamin B6 (pyridoxine 25mg 3 times daily)
• Acupressure wristbands (Sea-Bands)
• Rest and hydration
• Avoid triggers (smells, foods)
• Cool room
• Fresh air
• Avoid empty stomach

Medications by category:

Dramamine (Dimenhydrinate):

• Category B
• Considered generally safe
• Effective for pregnancy nausea
• Combined with B6 popular approach
• Watch for sedation

Maxolon (Metoclopramide):

• Category B
• Widely used in pregnancy
• Effective for moderate to severe
• Prokinetic benefit
• Limit duration due to tardive dyskinesia risk

Zofran (Ondansetron):

• Category B
• Very effective
• Reserved for severe cases (hyperemesis)
• Some studies suggest slight cardiac defect risk to fetus (debated)
• Individual assessment
• Off-label for pregnancy but widely used
• Discuss with obstetrician

Compazine (Prochlorperazine):

• Category C
• Generally avoided in early pregnancy
• May be used in later pregnancy if needed
• Extrapyramidal effects in newborn possible

Recommended approach by severity:

Mild:

• Non-drug approaches
• Ginger
• B6 (pyridoxine)
• Diet changes

Moderate:

• Add doxylamine (Unisom) + B6
• This combination = Diclegis
• Category A specifically for pregnancy
• Well-studied
• Now first-line

Moderate-severe:

• Metoclopramide
• Ondansetron
• Prochlorperazine (later pregnancy)
• IV hydration if needed

Severe (hyperemesis gravidarum):

• Hospitalization
• IV hydration
• IV antiemetics
• Nutritional support
• Multiple medications
• Sometimes prolonged treatment

Trimester considerations:

First trimester:

• Most sensitive period
• Peak nausea time
• Non-drug approaches emphasized
• Category A/B medications preferred
• Avoid unnecessary drugs

Second trimester:

• Nausea often improves
• May stop medications
• Continue if hyperemesis

Third trimester:

• Some develop late nausea
• Watch for preeclampsia signs
• Different considerations
• Consult obstetrician

Warning signs to seek care:

Dehydration prevention:

• Sip water frequently
• Popsicles
• Broth
• Sports drinks (moderate)
• IV fluids if needed

Nutrition maintenance:

• Any food you can tolerate
• Small amounts frequently
• Prenatal vitamins (may need alternate timing)
• Nutritional supplements if needed
• Consult dietitian

Emotional support:

• Nausea can be distressing
• Partner support
• Rest as needed
• Work accommodation
• Support groups
• Not weakness or failure

When to hospitalize:

• Severe dehydration
• Weight loss more than 5 percent
• Electrolyte abnormalities
• Cannot keep down any fluids
• Ketosis on urinalysis
• Failed outpatient treatment

Recovery expectations:

• Most improve by week 12-14
• Some persist longer
• Hyperemesis may last entire pregnancy
• Higher recurrence in next pregnancy
• Support and management important

What is tardive dyskinesia:

• Involuntary repetitive movements
• Usually affects face, mouth, tongue
• Can affect limbs and body
• Develops with prolonged medication use
• May be permanent even after stopping
• Increasing over time

Symptoms:

• Facial grimacing
• Lip smacking or puckering
• Tongue movements (chewing, protrusion)
• Rapid eye blinking
• Uncontrolled facial expressions
• Finger movements
• Toe wiggling
• Body swaying
• Muscle spasms

Medications causing TD:

From RXshop.md nausea medications:

• Metoclopramide (Maxolon) - BLACK BOX warning
• Prochlorperazine (Compazine)

Other TD-causing medications:

• All antipsychotics (haloperidol, risperidone, etc.)
• Some antidepressants
• Some antinausea medications
• All D2 dopamine blockers

Why these drugs cause TD:

• Block dopamine D2 receptors
• Brain adapts by making more receptors
• Dopamine sensitivity changes
• Movement control affected
• Continues even after stopping

Risk factors:

• Duration of use - MAIN factor
• Higher doses
• Older age
• Female gender
• Diabetes
• Underlying brain conditions
• Concurrent lithium
• Genetic factors

Time to develop:

• Usually months to years
• Younger patients faster
• Metoclopramide: 6+ months significant risk
• Prochlorperazine: similar
• Rare with short courses

Prevention strategies:

Metoclopramide specifically:

• LIMIT TO 12 WEEKS maximum
• Use lowest effective dose
• Regular assessment
• Discontinue if problems appear
• Do NOT restart if TD develops

Prochlorperazine:

• Short-term use only
• Alternative for chronic use
• Watch closely if prolonged
• Discontinue if signs appear

Regular monitoring:

• AIMS (Abnormal Involuntary Movement Scale)
• Every 3-6 months
• Detailed examination
• Family observations valuable
• Photograph or video changes

Recognizing early signs:

• Subtle facial movements
• Slight lip movements
• Occasional tongue movements
• Blink rate changes
• Family notices before patient

If TD develops:

Immediate steps:

• Stop offending medication (if safe)
• Do NOT restart
• Consult neurologist
• Document symptoms
• Baseline assessment

Treatment of TD:

• Difficult to treat
• May be irreversible
• Newer medications: valbenazine (Ingrezza), deutetrabenazine (Austedo)
• Vitamin E may help
• Some resolve slowly over years
• Symptomatic management

Reversibility:

• Some cases reversible over time
• Others permanent
• Younger patients better recovery
• Shorter exposure better outcomes
• Cannot predict who will recover

Alternative safer medications:

• Ondansetron (Zofran) - no TD risk
• Dimenhydrinate (Dramamine) - different mechanism
• Non-drug approaches

For gastroparesis (need for metoclopramide):

• Difficult balance
• Domperidone (some countries)
• Erythromycin
• Dietary approaches
• Gastric electrical stimulation
• Careful metoclopramide use

Discussing with doctor:

• Ask about duration
• Understand risks
• Regular monitoring plan
• Family aware of signs
• Prompt evaluation of symptoms

Legal considerations:

• BLACK BOX warning on metoclopramide since 2009
• Informed consent important
• Documented duration of use
• Regular assessment

Other side effects of dopamine blockers to watch:

Acute dystonia:

• Sudden muscle contractions
• Often first few days
• Face, neck, tongue
• Emergency treatment with diphenhydramine

Akathisia:

• Severe restlessness
• Cannot sit still
• Distressing
• Reduce dose or discontinue

Parkinsonism:

• Slowness
• Tremor
• Rigidity
• Different from tardive dyskinesia

Neuroleptic malignant syndrome:

• High fever
• Muscle rigidity
• Confusion
• Life-threatening
• Emergency

Prevention approach:

• Use safer alternatives when possible
• Short-term when needed
• Regular monitoring
• Aware of signs
• Prompt discontinuation
• Discuss with doctor

QT prolongation is a heart rhythm abnormality that can be caused by ondansetron, potentially leading to serious arrhythmias in susceptible individuals.

What is QT interval:

• Measured on ECG
• Time between heartbeat electrical events
• Represents heart repolarization
• Normal QT: less than 450ms (women 460ms)
• Prolonged when longer

Why prolongation is concerning:

• Can lead to torsades de pointes (dangerous rhythm)
• Sudden cardiac death possible
• Fainting
• Palpitations

Ondansetron's effect on QT:

• Blocks potassium channels in heart
• Delays repolarization
• Prolongs QT interval
• Effect dose-dependent
• Higher doses = higher risk

Risk levels:

• Standard oral doses: usually low risk
• IV doses: moderate risk
• High doses: significant risk
• Above 32mg IV single dose: NOT recommended

Who is at higher risk:

• Congenital long QT syndrome
• Cardiac history
• Bradycardia
• Heart failure
• Elderly
• Electrolyte imbalances (low potassium, low magnesium)
• Kidney disease
• Liver disease
• Multiple QT-prolonging medications

Dangerous drug combinations:

Other QT-prolonging medications:

• Antipsychotics (haloperidol, olanzapine)
• Some antibiotics (macrolides, fluoroquinolones)
• Some antifungals (fluconazole, ketoconazole)
• Some antidepressants (SSRIs, tricyclics)
• Methadone
• Antiarrhythmic drugs
• Some cancer drugs

Screening before ondansetron:

Consider ECG in high-risk patients:

• Known cardiac disease
• Elderly with comorbidities
• Multiple QT-prolonging drugs
• Chemotherapy patients
• Baseline abnormalities

Electrolyte monitoring:

• Potassium
• Magnesium
• Calcium
• Correct before treatment
• Especially in chemotherapy patients

Warning signs:

Dose considerations:

Oral ondansetron:

• Standard 4-8mg: relatively low risk
• Chemotherapy 16-24mg: moderate risk
• Higher doses: caution

IV ondansetron:

• Standard 4mg: usually safe
• 8mg: some risk
• 16mg: significant risk
• 32mg single dose: NO LONGER RECOMMENDED
• 16mg IV max single dose

Special situations:

Chemotherapy patients:

• Common QT issues
• Electrolyte imbalances common
• Multiple drug interactions
• Cardiac monitoring often
• ECG surveillance

Post-operative patients:

• Recent anesthesia effects
• Electrolyte shifts
• Consider risk

Pregnancy:

• Some studies suggest slight cardiac defect risk to fetus
• Debated evidence
• Discuss risk/benefit

Alternative antiemetics if high QT risk:

• Dimenhydrinate (Dramamine) - no significant QT effect
• Metoclopramide (Maxolon) - some QT effect but usually less
• Corticosteroids for chemotherapy nausea
• NK1 antagonists
• Newer agents

Monitoring during treatment:

• ECG at baseline for high-risk patients
• Repeat ECG if concerns
• Electrolyte monitoring
• Symptom awareness
• Report cardiac symptoms

Correcting risk factors:

• Replace low potassium
• Replace low magnesium
• Address other cardiac issues
• Review all medications
• Discontinue unnecessary QT-prolonging drugs

When benefits outweigh risks:

• Severe chemotherapy nausea
• Life-threatening dehydration
• No effective alternatives
• Careful monitoring
• Informed consent

Discussing with doctor:

• Complete medication list
• Cardiac history
• Family history sudden death
• Previous ECG abnormalities
• Prior arrhythmias
• Fainting history

Long-term perspective:

• Most patients tolerate ondansetron well
• Serious cardiac events uncommon
• Balance risks with severe nausea
• Individual assessment
• Ongoing monitoring

Post-operative nausea and vomiting (PONV) affects approximately 30 percent of surgical patients. Prevention is more effective than treatment.

Risk factors for PONV:

Patient factors:

• Female gender
• History of PONV
• History of motion sickness
• Non-smoker
• Younger age
• Anxiety disorder

Surgical factors:

• Type of surgery (gynecologic, ENT, laparoscopic highest risk)
• Duration of surgery
• Blood loss
• Bowel manipulation

Anesthetic factors:

• Volatile anesthetics
• Nitrous oxide
• Opioid use
• Duration of anesthesia

Risk stratification:

Low risk (0-1 factors):

• 10 percent chance of PONV
• May not need prophylaxis

Moderate risk (2 factors):

• 30-40 percent chance
• Single antiemetic prophylaxis

High risk (3+ factors):

• 60-80 percent chance
• Multi-modal prophylaxis
• Combination antiemetics

Prevention strategies:

Multi-modal approach:

• Combine different mechanism drugs
• Lower doses of each
• Better efficacy
• Reduced side effects

Ondansetron (main option):

• Zofran 4mg IV at end of surgery
• Or 4-8mg oral before surgery
• Highly effective
• No sedation
• Well-tolerated

Dexamethasone:

• Steroid antiemetic
• 4-8mg IV at induction
• Combined with ondansetron
• Also helps pain

Droperidol:

• Effective but boxed warning
• Cardiac concerns
• Less used now

Metoclopramide:

• Maxolon alternative
• Modest effect
• Combined with others

Scopolamine patch:

• Applied before surgery
• Prevents motion-related nausea
• Long-lasting

Optimal timing:

Ondansetron:

• End of surgery (short half-life for early PONV)
• Repeat 6-8 hours if needed

Dexamethasone:

• Induction of anesthesia
• Long-lasting effect

Scopolamine patch:

• 2-4 hours before surgery
• Effect lasts 3 days

Anesthetic techniques to reduce PONV:

• Total IV anesthesia (propofol-based)
• Avoid nitrous oxide when possible
• Minimize opioids
• Regional anesthesia when appropriate
• Adequate hydration during surgery

Post-operative management:

If nausea occurs despite prophylaxis:

• Use different drug class than prophylaxis
• Ondansetron rescue if not used for prophylaxis
• Prochlorperazine
• Promethazine
• IV fluids

Non-drug approaches:

• Aromatherapy (isopropyl alcohol wipe)
• Acupressure P6 point
• Cool cloth on forehead
• Slow deep breathing
• Ginger
• Slow return to oral intake

Dietary progression:

• Ice chips first
• Small sips of water
• Clear liquids
• Bland foods (crackers)
• Gradual progression
• Small amounts frequently

Post-discharge nausea:

• Take home antiemetics
• Ondansetron ODT useful
• Instructions for management
• When to call doctor

When to seek medical care:

• Persistent vomiting 24+ hours
• Cannot keep fluids down
• Signs of dehydration
• Fever
• Severe abdominal pain
• Vomiting blood

Special situations:

Children:

• Different risk profile
• Ondansetron widely used
• Age-appropriate dosing
• Watch for dehydration

Elderly:

• May tolerate nausea worse
• Fewer medication options
• Ondansetron often preferred
• Avoid sedating antihistamines

Cesarean section:

• High PONV risk
• Ondansetron routinely
• Consider prophylaxis

Day surgery:

• Take-home antiemetics important
• Address before discharge
• Prevention preferred to treatment

Long-term perspective:

• Modern prophylaxis very effective
• Most patients avoid PONV
• Comprehensive approach best
• Communication with anesthesia team

Antiemetics have varying side effect profiles based on their mechanism. Understanding differences helps choose appropriate medication.

Ondansetron (Zofran) side effects:

Common (usually mild):

• Headache (very common)
• Constipation
• Fatigue
• Dizziness
• Dry mouth
• Diarrhea (paradoxical)

Uncommon:

• Elevated liver enzymes
• Injection site reactions
• Fever

Serious but rare:

• QT prolongation
• Arrhythmias
• Serotonin syndrome (with other serotonergic drugs)
• Severe hypersensitivity reactions
• Anaphylaxis

Metoclopramide (Maxolon) side effects:

Common:

• Drowsiness
• Restlessness
• Fatigue
• Depression
• Diarrhea
• Menstrual changes
• Breast tenderness

Serious:

• Tardive dyskinesia (BLACK BOX)
• Acute dystonia
• Parkinson-like symptoms
• Akathisia (severe restlessness)
• Neuroleptic malignant syndrome (rare)
• Suicidal thoughts
• QT prolongation

Prochlorperazine (Compazine) side effects:

Common:

• Drowsiness (very common)
• Dizziness
• Dry mouth
• Blurred vision
• Constipation
• Weight gain
• Photosensitivity

Serious:

• Extrapyramidal symptoms
• Acute dystonic reactions
• Tardive dyskinesia (long-term)
• Akathisia
• Neuroleptic malignant syndrome
• Orthostatic hypotension
• Blood cell changes
• Liver toxicity
• QT prolongation

Dimenhydrinate (Dramamine) side effects:

Common (anticholinergic):

• Drowsiness (very common)
• Dry mouth
• Blurred vision
• Constipation
• Urinary retention
• Coordination issues
• Dizziness

Less common:

• Confusion (elderly)
• Rapid heart rate
• Skin rash
• Photosensitivity
• Paradoxical excitement (children rare)

Comparing sedation levels:

Managing common side effects:

Constipation (ondansetron):

• High fiber diet
• Adequate fluids
• Exercise
• Stool softeners if needed
• Usually resolves

Drowsiness:

• Take at bedtime if possible
• Avoid alcohol
• Do NOT drive
• Reduce dose if severe
• Consider alternative medication

Dry mouth:

• Sip water frequently
• Sugar-free gum
• Hard candies
• Good dental care
• Saliva substitutes

Restlessness (akathisia):

• Common with metoclopramide, prochlorperazine
• Very distressing
• Report immediately
• Reduce dose or switch
• Benzodiazepines can help

Warning signs requiring immediate attention:

Managing severe reactions:

Dystonic reaction (acute):

• Diphenhydramine 50mg IV/IM
• Benztropine 1-2mg
• Resolves in minutes
• May recur if drug continued

Akathisia:

• Discontinue offending drug
• Beta-blockers help
• Benzodiazepines
• Reduce dose

Neuroleptic malignant syndrome:

• Fever
• Muscle rigidity
• Autonomic instability
• EMERGENCY
• Discontinue drug
• Hospital treatment

Age-specific considerations:

Elderly:

• Increased sensitivity
• Anticholinergic burden concern
• Higher falls risk
• Confusion risk
• Ondansetron preferred often

Children:

• Ondansetron approved
• Weight-based dosing
• Watch dehydration
• Age-appropriate education

When to change medication:

• Intolerable side effects
• Ineffective
• Serious adverse effects
• Interactions
• Change of condition
• Try different class

Long-term use considerations:

• Metoclopramide - 12 weeks max
• Prochlorperazine - limit duration
• Ondansetron - can be longer
• Dimenhydrinate - occasional use
• Regular reassessment

Signs of dehydration:

Mild-moderate:

• Thirst
• Dry mouth
• Reduced urination
• Dark yellow urine
• Fatigue
• Headache

Severe (emergency):

• No urination 12+ hours
• Very dark urine
• Rapid heart rate
• Rapid breathing
• Sunken eyes
• Skin lacks elasticity
• Confusion
• Fainting
• Very low blood pressure

Warning signs of serious conditions:

Appendicitis:

• Pain around navel then right lower quadrant
• Fever
• Loss of appetite
• Rebound tenderness
• Surgical emergency

Bowel obstruction:

• Severe cramping pain (comes in waves)
• Inability to pass gas or stool
• Abdominal distension
• Vomiting (may be fecal)
• Loud bowel sounds initially

Pancreatitis:

• Severe upper abdominal pain
• Radiates to back
• Worse after eating
• Vomiting persistent
• Fever

Meningitis:

• Fever
• Severe headache
• Stiff neck
• Photophobia
• Rash (some types)
• Confusion

Increased intracranial pressure:

• Severe morning headache
• Vomiting without nausea
• Vision changes
• Neurological signs
• Requires imaging

Stroke:

• Sudden vomiting
• Facial droop
• Arm weakness
• Speech difficulty
• Confusion
• Emergency

Diabetic ketoacidosis:

• High blood sugar
• Vomiting
• Deep rapid breathing
• Fruity breath
• Confusion
• Emergency

Poisoning:

• Recent exposure
• Multiple symptoms
• Contact poison control
• 1-800-222-1222 (US)

Contact doctor promptly (not emergency but urgent) for:

• Persistent vomiting more than 12 hours
• Cannot keep down medications
• Chronic conditions worsening
• Multiple family members ill
• Recent travel
• Recent antibiotics
• Weight loss
• Recurring episodes

Special situations:

Pregnancy:

• Any severe vomiting
• Weight loss more than 5 percent
• Signs of dehydration
• Cannot keep down anything
• May be hyperemesis gravidarum
• Contact obstetrician

Children:

• Lower threshold for concern
• Dehydrate faster than adults
• Vomiting in infant under 3 months
• Cannot keep down anything
• Signs of dehydration
• Fever
• Bloody vomit
• Green vomit
• Contact pediatrician

Elderly:

• Dehydrate faster
• Underlying conditions
• Medications complicate
• Falls risk
• Lower threshold for evaluation

Immunocompromised:

• Cancer patients
• HIV positive
• Transplant recipients
• Higher risk of serious causes
• Prompt evaluation important

Post-surgical:

• Contact surgical team
• May indicate complication
• Some vomiting expected
• Persistent needs evaluation

After medications:

• New medication may cause
• Cannot keep down important medications
• Contact prescribing doctor
• May need alternative

Home management if not emergency:

Hydration approach:

• Small sips frequently
• Ice chips
• Oral rehydration solution
• Sports drinks (moderate)
• Clear broths
• Popsicles

When to start medications:

• Persistent nausea
• Cannot maintain hydration
• Specific triggers (motion, chemotherapy)
• Consult healthcare provider

Diet progression:

• Nothing for 1-2 hours after vomiting
• Then small sips
• Clear liquids
• Bland foods (BRAT diet)
• Gradual normal diet

Rest and comfort:

• Cool room
• Fresh air
• Avoid strong smells
• Comfortable position
• Sit upright
• Head elevated

Preparing for medical evaluation:

• Note timing and pattern
• Associated symptoms
• Recent illnesses
• Recent travel
• Recent foods
• Recent medications
• Medical history
• Medications list

Follow-up after emergency:

• Understand diagnosis
• Follow discharge instructions
• Take medications as prescribed
• Follow-up appointments
• When to return
• Prevention strategies

Antiemetics can interact with many medications. Some combinations enhance treatment, others are dangerous. Complete medication disclosure to prescribers essential.

Antiemetic-Antiemetic combinations:

Beneficial combinations:

Ondansetron + Dexamethasone:

• Standard chemotherapy prophylaxis
• Different mechanisms
• Enhanced efficacy
• Standard combination

Ondansetron + NK1 antagonist:

• Highly emetogenic chemotherapy
• Triple therapy standard
• Best efficacy

Dangerous combinations of antiemetics:

Multiple dopamine blockers:

• Metoclopramide + prochlorperazine
• Movement disorder risk multiplied
• Avoid combination

Multiple QT-prolonging antiemetics:

• Cardiac risk
• Careful selection

Interactions with other medications:

Ondansetron interactions:

Serotonergic drugs (serotonin syndrome risk):

• SSRIs (fluoxetine, sertraline, paroxetine)
• SNRIs (venlafaxine, duloxetine)
• Tramadol
• MAO inhibitors
• St. Johns wort
• Fentanyl

QT-prolonging drugs:

• Antipsychotics
• Some antibiotics
• Some antifungals
• Methadone
• Antiarrhythmics

Apomorphine:

• Dangerous combination
• Severe hypotension
• Do NOT combine

Metoclopramide interactions:

Dangerous:

• Antipsychotics (movement disorders)
• MAO inhibitors
• Digoxin (reduced levels)
• Cyclosporine (increased levels)
• Levodopa (reduced effect for Parkinson)

Caution:

• CNS depressants (additive sedation)
• Alcohol
• Opioids
• Other serotonergic drugs

Prochlorperazine interactions:

Dangerous:

• Other antipsychotics (movement disorders)
• MAO inhibitors
• Metoclopramide (movement disorders)
• Meperidine (dangerous CNS effects)

Caution:

• Alcohol (extreme sedation)
• Other CNS depressants
• Anticholinergics
• Antihypertensives
• Anticonvulsants

Dimenhydrinate interactions:

Additive anticholinergic effects:

• Tricyclic antidepressants
• Antihistamines (other)
• Antipsychotics
• Bladder medications (oxybutynin)
• Antiparkinson drugs

Additive sedation:

• Alcohol
• Benzodiazepines
• Opioids
• Sleep medications
• Muscle relaxants

Antibiotic interactions:

Erythromycin, clarithromycin:

• QT prolongation additive
• Especially with ondansetron
• Careful monitoring

Fluoroquinolones (levofloxacin, ciprofloxacin):

• QT prolongation additive
• Especially with ondansetron
• Discuss with prescriber

Antifungal interactions:

Ketoconazole, itraconazole:

• Can increase ondansetron levels
• Cardiac risk potential
• QT concerns

Antidepressant interactions:

SSRIs, SNRIs:

• Serotonin syndrome with ondansetron
• Rare but serious
• Symptoms: agitation, confusion, tremor, sweating, fever
• Emergency if suspected

Tricyclic antidepressants:

• Additive anticholinergic (dimenhydrinate)
• QT effects
• CNS depression

MAO inhibitors:

• Multiple dangerous interactions
• 14-day washout period
• Avoid combination

Pain medication interactions:

Opioids:

• Cause their own nausea (opioid-induced)
• Antiemetics often needed with opioids
• Ondansetron doesn't worsen constipation as much
• Prochlorperazine adds sedation
• Watch for combined side effects

NSAIDs:

• Can cause nausea
• Combined use often necessary
• Less interaction concerns

Blood pressure medications:

Antihypertensives:

• Prochlorperazine can lower BP
• Dimenhydrinate can affect BP
• Monitor blood pressure

Diabetes medications:

Metoclopramide:

• Affects gastric emptying
• May change insulin timing
• Adjust as needed

Alcohol interactions:

All antiemetics:

• Additive sedation with alcohol
• Impaired coordination
• Worse with prochlorperazine, dimenhydrinate
• Avoid combination
• Especially with driving

Recreational drugs:

• Various dangerous interactions
• Discuss honestly with doctor
• Cocaine + ondansetron QT concerns
• Marijuana + prochlorperazine sedation

Herbal supplements:

St. Johns wort:

• Serotonergic effects
• Combined with ondansetron: serotonin syndrome
• Reduces other drug levels
• Discuss with doctor

Ginger:

• Generally safe antiemetic
• Can supplement medications
• Anti-nausea properties

Prevention of interactions:

• Complete medication list to ALL providers
• Include OTC medications
• Include supplements
• Include herbal medicines
• Include alcohol use
• Consistent pharmacy
• Pharmacist consultation
• Regular review

Warning signs of interactions:

• New symptoms after starting medication
• Extreme sedation
• Fever with muscle rigidity
• Agitation, confusion
• Tremor
• Rapid heart rate
• Bleeding or bruising
• Report immediately

Special situations:

Chemotherapy:

• Multi-drug regimens
• Coordinate with oncology
• Standard prophylaxis
• Rescue medications

Multiple health conditions:

• Careful medication selection
• Coordinate providers
• Regular reviews
• Watch for cumulative effects

Elderly:

• Higher interaction risk
• Multiple medications common
• Anticholinergic burden
• Regular medication reviews

Non-medication approaches can effectively relieve mild to moderate nausea and complement medications for severe cases. Often preferred first, especially in pregnancy.

Ginger (Most Studied Natural Remedy):

Evidence:

• Multiple clinical trials support use
• Effective for pregnancy nausea
• Motion sickness
• Post-operative nausea
• Chemotherapy adjunct

How to use:

• Fresh ginger tea (boil sliced ginger)
• Ginger candies
• Ginger ale (real ginger)
• Crystallized ginger
• Ginger capsules (250-500mg 4 times daily)
• Ginger cookies

Dosing:

• 1-2 grams daily typically
• Divided doses
• Effect within 30 minutes

Precautions:

• Blood thinning effect (moderate)
• Discuss if on warfarin
• Safe in pregnancy

Vitamin B6 (Pyridoxine):

• Excellent for pregnancy nausea
• 25mg 3 times daily
• Combined with doxylamine effective
• Diclegis is B6 + doxylamine
• Safe in pregnancy
• Well-tolerated

Acupressure:

P6 (Pericardium 6) point:

• Three finger widths from wrist crease
• Between two tendons
• Sustained pressure
• Both wrists

Sea-Bands:

• Wristbands with plastic bead
• Apply pressure to P6
• Effective for motion sickness
• Some use for pregnancy
• Non-invasive
• Available over-counter

Acupuncture:

• Trained practitioner
• Multiple sessions typical
• Some evidence for chemotherapy nausea
• Complementary approach

Dietary approaches:

Small frequent meals:

• Avoid empty stomach
• Every 2-3 hours
• Prevents blood sugar drops
• Reduces reflux

Bland foods (BRAT diet):

• Bananas
• Rice
• Applesauce
• Toast
• Easy to digest
• Low fiber initially
• Progress as tolerated

Foods that help:

• Crackers (before rising)
• Ginger foods
• Peppermint (some)
• Cold foods (less smell)
• Popsicles
• Clear broths
• Plain yogurt

Foods to avoid:

• Greasy foods
• Spicy foods
• Strong smelling foods
• Very hot foods
• Very sweet foods
• Caffeine (excess)
• Alcohol

Hydration:

Critical:

• Dehydration worsens nausea
• Sip water frequently
• Ice chips
• Popsicles
• Clear broths

Oral rehydration solutions:

• Better than plain water for severe
• Pedialyte
• Gastrolyte
• Homemade options
• Sports drinks (moderate)

What to avoid:

• Excessive plain water (worsens electrolytes)
• Sugary drinks (worsen dehydration sometimes)
• Alcohol
• Excessive caffeine

Environmental modifications:

Cool environment:

• Reduces nausea sensation
• Fan
• Air conditioning
• Cool wet cloth on forehead

Fresh air:

• Open windows
• Outside if possible
• Deep breathing
• Reduces triggers

Avoid strong smells:

• Perfumes
• Cooking odors
• Cleaning products
• Cigarette smoke
• Others cooking for you

Aromatherapy:

• Peppermint (some evidence)
• Lemon
• Ginger essential oil
• Isopropyl alcohol wipes (surgery)
• Individual response

Position and rest:

• Sit upright
• Head elevated
• Avoid lying flat
• Rest as needed
• Comfortable position
• Avoid sudden movements

Behavioral techniques:

Deep breathing:

• Slow deep breaths
• Through nose
• Reduces nausea
• Calming effect

Distraction:

• Music
• TV or movies
• Reading (if not triggering)
• Conversation

Meditation and relaxation:

• Reduces stress-nausea
• Guided imagery
• Progressive muscle relaxation
• Mindfulness

Hypnotherapy:

• Some evidence for chemotherapy
• Trained therapist
• Complementary approach

For motion sickness specifically:

• Look at horizon
• Sit facing forward
• Avoid reading
• Fresh air
• Cool environment
• Small snacks before travel
• Sea-Bands
• Ginger before travel

For pregnancy nausea:

• Crackers before rising
• Small frequent meals
• Ginger
• B6
• Acupressure
• Avoid strong smells
• Rest

For chemotherapy nausea:

• Small frequent meals
• Cool bland foods
• Ginger
• Acupressure
• Distraction
• Meditation
• Combined with medications

For post-op nausea:

• Aromatherapy (isopropyl alcohol wipe)
• Acupressure
• Slow oral intake progression
• Fresh air
• Rest

Herbal remedies (with caution):

Peppermint:

• Tea
• Candies
• Some antiemetic effect
• Can worsen GERD

Chamomile:

• Tea
• Mild calming effect
• Some digestive benefit

Fennel:

• Traditional remedy
• Tea or seeds
• Some benefit

When non-drug approaches insufficient:

• Severe symptoms
• Cannot maintain hydration
• Weight loss
• Underlying serious cause
• Add medications
• Consult healthcare provider

Combined approach best:

• Non-drug + medications
• Multiple mechanisms
• Comprehensive treatment
• Better outcomes

Individual response varies:

• What works for one may not for another
• Try different approaches
• Track what helps
• Personalize approach
• Not one-size-fits-all

Children with nausea and vomiting need special consideration for dosing, medication choice, and dehydration prevention.

Common causes in children:

• Gastroenteritis (stomach flu)
• Food poisoning
• Motion sickness
• Migraine
• Post-operative
• Concussion
• Chemotherapy
• Overeating
• Anxiety

Rapid dehydration in children:

• Children dehydrate faster than adults
• Higher water percentage of body
• Higher metabolic rate
• Cannot compensate as well
• Watch signs carefully

Signs of dehydration in children:

Mild:

• Fewer wet diapers
• Thirsty
• Slightly dry mouth
• Behavior changes

Moderate:

• Sunken eyes
• Very dry mouth
• No tears when crying
• Fewer than 6 wet diapers per day
• Fatigue

Severe (emergency):

• No urine 8-12 hours
• Sunken soft spot (infants)
• Cold hands and feet
• Rapid breathing
• Lethargy
• Not responding normally
• Emergency care needed

Medications for children:

Zofran (Ondansetron) for children:

• Approved for age 4+ (some ages younger with caution)
• Widely used
• Weight-based dosing
• Available as dissolving tablet
• Great for gastroenteritis
• Prevents dehydration

Ondansetron dosing children:

• 8-15 kg: 2mg
• 15-30 kg: 4mg
• Over 30 kg: 8mg
• Every 8 hours as needed

Dramamine (Dimenhydrinate) for children:

• Age 2 and older
• Motion sickness main use
• Weight-based dosing
• Watch for paradoxical excitement

Dimenhydrinate dosing:

• Children 2-6 years: 12.5-25mg every 6-8 hours
• Children 6-12 years: 25-50mg every 6-8 hours
• Not for under 2

Maxolon (Metoclopramide) for children:

• Can be used but with caution
• Higher extrapyramidal risk in children
• Weight-based dosing
• Age 1+ typically

Compazine (Prochlorperazine) for children:

• NOT for children under 2 years
• Age 2+ with weight limits
• Higher extrapyramidal risk
• Alternative preferred usually

Rehydration approach:

Oral rehydration solutions:

• Pedialyte
• Enfalyte
• Correct electrolyte balance
• Better than water alone
• Better than juice or soda
• Small frequent amounts

Amount to give:

• 50-100 mL/kg over 2-4 hours (mild dehydration)
• 100-200 mL/kg over 4 hours (moderate)
• 5 mL every 5 minutes if actively vomiting
• Increase amounts as tolerated

What NOT to give:

• Plain water in large amounts (electrolyte imbalance)
• Sugary drinks (worsen diarrhea)
• Fruit juices (too much sugar)
• Sports drinks (except older children)
• Milk (may worsen)
• Chicken broth alone (too salty)

When to introduce food:

• After no vomiting for 2-4 hours
• Start with bland foods
• BRAT diet initially
• Progress as tolerated
• Small amounts

Age-appropriate foods:

Infants:

• Continue breastfeeding if possible
• Small frequent formula feeds
• Oral rehydration solutions

Toddlers:

• Bananas
• Rice cereal
• Toast
• Yogurt
• Crackers

Older children:

• BRAT diet
• Boiled potatoes
• Plain pasta
• Popsicles
• Broth

Non-medication approaches for children:

• Rest in cool room
• Popsicles
• Ice chips
• Distraction
• Ginger ale (real ginger)
• Small sips frequently
• Fresh air

Motion sickness in children:

• Common problem
• Face forward
• Look at horizon
• Avoid reading during travel
• Cool environment
• Fresh air
• Dramamine 30-60 min before
• Sea-Bands (older children)
• Distraction

Chemotherapy in children:

• Ondansetron widely used
• Age-appropriate dosing
• Prophylactic approach
• Multi-drug regimens
• Dexamethasone often added
• Watch for nutrition impact

When to see doctor:

• Vomiting more than 24 hours
• Signs of dehydration
• Blood in vomit
• Green vomit
• Severe abdominal pain
• High fever
• Lethargy
• Not urinating
• Recent head injury
• Cannot keep down anything

Emergency signs (call 911 or ER):

• Severe dehydration signs
• Not responding normally
• Blood or bile in vomit
• Very severe pain
• Signs of meningitis
• Recent head injury
• Cannot arouse

Age-specific considerations:

Infants (under 1 year):

• Dehydration rapid and serious
• Low threshold for medical evaluation
• Continued vomiting concerning
• Weight loss significant
• Fewer wet diapers
• Contact pediatrician promptly

Toddlers (1-3 years):

• Cannot verbalize symptoms well
• Watch behavior
• Playful and interactive good sign
• Lethargy concerning
• Small frequent fluids

School age:

• Can communicate
• Follow instructions
• May resist medications
• Explain what happening
• Reward for cooperation

Adolescents:

• Adult-like dosing
• Include in treatment decisions
• Explain rationale
• Manage anxiety

Comfort measures:

• Cool washcloth on forehead
• Quiet environment
• Familiar comfort items
• Reassurance
• Physical comfort
• Reduce anxiety

Prevention:

• Handwashing
• Food safety
• Water safety
• Avoid sick contacts
• Vaccinations (rotavirus)
• Motion sickness pre-treatment

Many causes beyond typical illness can trigger nausea. Understanding causes helps address root problems.

Medications causing nausea:

Common culprits:

• Antibiotics (many)
• NSAIDs (ibuprofen, aspirin)
• Opioids
• Iron supplements
• Metformin (diabetes)
• Chemotherapy
• Digoxin
• Antidepressants (SSRIs, SNRIs)
• Antipsychotics
• Antifungals

Management:

• Take with food when possible
• Discuss with prescriber
• Alternative medications
• Add antiemetic
• Split dose

Chemotherapy-Induced Nausea:

• 70 percent affected without prophylaxis
• Different phases (acute, delayed, anticipatory)
• Ondansetron mainstay treatment
• Combined with other agents

Radiation Therapy:

• Depends on radiation site
• Upper abdomen highest risk
• Whole body irradiation
• Cranial radiation
• Preventive antiemetics

Post-Operative Nausea:

• 30 percent of patients
• Anesthesia effects
• Opioid pain medications
• Type of surgery matters
• Multi-modal prophylaxis

Motion Sickness:

• 1 in 3 people susceptible
• Cars, boats, planes
• Amusement park rides
• Virtual reality
• Prevention easier than treatment

Vestibular Disorders:

Vertigo causes nausea:

• Benign paroxysmal positional vertigo (BPPV)
• Vestibular neuritis
• Labyrinthitis
• Meniere disease
• Vestibular migraine
• Acoustic neuroma

Migraine:

• 90 percent of migraines have nausea
• Combined nausea and headache treatment
• Metoclopramide preferred
• Enhances absorption of headache meds

Pregnancy:

• 50-80 percent of pregnancies
• Peak first trimester
• Hyperemesis gravidarum in 1-2 percent
• Hormonal changes
• Improves after week 12-14

Menstrual/Hormonal:

• Some women have nausea with periods
• Hormonal fluctuations
• PMS component
• Menopause

Psychological Causes:

Anxiety:

• Anxiety-related nausea common
• Panic attacks
• Stomach knot sensation
• Anticipatory nausea
• Address underlying anxiety

Depression:

• Physical symptoms including nausea
• Loss of appetite
• Address underlying depression

PTSD:

• Trauma-related nausea
• Trigger-related
• Trauma-focused therapy

Eating Disorders:

• Anorexia
• Bulimia
• Complex causes
• Multidisciplinary treatment

Metabolic Causes:

Diabetic ketoacidosis:

• Emergency
• High blood sugar
• Ketones
• Nausea, vomiting
• Deep rapid breathing

Uremia (kidney failure):

• Toxin buildup
• Persistent nausea
• Address kidney disease

Hyperthyroidism:

• Thyroid overactivity
• Multiple symptoms
• Include nausea

Adrenal insufficiency:

• Hormone deficiency
• Fatigue, nausea
• Requires hormone replacement

Electrolyte imbalances:

• Low sodium
• Low potassium
• High or low calcium
• Correction essential

Cardiovascular:

Heart attack:

• Can present with nausea only
• Especially in women
• Especially in diabetics
• Consider if risk factors

Heart failure:

• Right-sided causes nausea
• Gut congestion

Neurological:

Migraine:

• Most common neurological cause
• Very common nausea

Concussion:

• Head trauma
• Nausea common
• Requires evaluation
• Rest important

Increased intracranial pressure:

• Brain tumors
• Hydrocephalus
• Meningitis
• Morning vomiting
• Serious causes

Stroke:

• Vertebrobasilar strokes
• Nausea, dizziness
• Emergency

Gastrointestinal:

Peptic ulcer disease:

• Stomach or duodenal ulcers
• Nausea common
• Address H pylori if present

GERD:

• Acid reflux
• Regurgitation
• Related nausea

Gastroparesis:

• Delayed gastric emptying
• Diabetic complication
• Metoclopramide helpful

Inflammatory bowel disease:

• Crohn disease
• Ulcerative colitis
• Nausea during flares

Appendicitis:

• Emergency
• Nausea, vomiting
• Abdominal pain

Bowel obstruction:

• Emergency
• Cannot pass gas/stool
• Abdominal distension

Environmental Triggers:

• Strong smells
• Motion
• Bright lights (migraine)
• Heat
• Poor air quality

Food-Related:

• Food poisoning
• Overeating
• Certain foods (individual)
• Food intolerances
• Allergies
• Excessive alcohol

Substance-Related:

• Alcohol excess
• Marijuana (some users)
• Withdrawal syndromes
• Overdose situations

Rare Causes:

• Cyclic vomiting syndrome
• Rumination syndrome
• Cannabinoid hyperemesis syndrome
• Mesenteric ischemia

When cause unclear:

Evaluation:

• Detailed history
• Physical examination
• Blood tests
• Urinalysis
• Pregnancy test if applicable
• Imaging (CT, ultrasound)
• Endoscopy sometimes

Address underlying cause:

• Symptomatic treatment temporary
• Cause needs identification
• Specific treatment better
• Long-term prevention

When persistent:

• See doctor for evaluation
• Do not just treat symptoms
• Underlying cause important
• May be serious condition

Elderly patients require special consideration when using antiemetics due to increased sensitivity to side effects and higher risks of certain complications.

Age-related considerations:

Reduced drug metabolism:

• Slower liver metabolism
• Reduced kidney clearance
• Longer drug effects
• Higher blood levels
• Need for dose adjustment

Increased sensitivity:

• More sedation
• More confusion
• Higher falls risk
• Cognitive effects worse
• Anticholinergic burden concern

Best options for elderly:

Ondansetron (Zofran):

• Generally preferred
• Minimal sedation
• No anticholinergic effects
• Watch for QT prolongation
• Cardiac evaluation important
• Dose adjustment may not be needed

Avoid in elderly:

Compazine (Prochlorperazine):

• Higher extrapyramidal risk
• Tardive dyskinesia more common
• Orthostatic hypotension
• Falls risk
• Sedation
• Consider alternatives

Dramamine (Dimenhydrinate):

• Anticholinergic burden
• Confusion risk
• Falls risk
• Cognitive effects
• Beers Criteria potentially inappropriate
• Meclizine may be safer

Use with caution:

Maxolon (Metoclopramide):

• Higher tardive dyskinesia risk in elderly
• Higher extrapyramidal risk
• Cognitive effects
• Limit to 12 weeks maximum
• Regular assessment
• Lower doses

Beers Criteria (potentially inappropriate for elderly):

• Dimenhydrinate - anticholinergic burden
• Metoclopramide - movement disorders
• Some prochlorperazine uses
• Consider alternatives
• Individual assessment

Anticholinergic burden concern:

• Cumulative effect of multiple drugs
• Cognitive decline association
• Dementia risk
• Falls risk
• Confusion
• Urinary retention
• Constipation
• Blurred vision

Falls risk:

• Sedation-causing antiemetics
• Postural hypotension
• Dizziness
• Coordination effects
• Serious consequences in elderly
• Assess before prescribing

Multiple medications (polypharmacy):

• Elderly on multiple drugs
• Interaction risk high
• Complete medication review
• Deprescribe when possible
• Consistent pharmacy

Common conditions in elderly requiring antiemetics:

Chemotherapy:

• Ondansetron preferred
• Consider cardiac status
• Dexamethasone often added
• Standard prophylaxis

Post-operative:

• Ondansetron IV
• Multi-modal approach
• Avoid sedating options
• Monitor for delirium

Motion sickness:

• Dimenhydrinate with caution
• Meclizine may be preferred
• Non-drug approaches
• Scopolamine patch alternative

Vertigo:

• Complex in elderly
• Multiple causes
• Vestibular rehabilitation
• Careful medication selection

Gastroparesis:

• Common in diabetic elderly
• Metoclopramide with careful monitoring
• Limited duration
• Non-drug approaches emphasized

Migraine:

• Less common in elderly (usually improves)
• New-onset requires evaluation
• Rule out serious causes
• Ondansetron often used

Post-viral illness:

• Common cause
• Address hydration priority
• Ondansetron effective
• Prevent dehydration complications

Dehydration risk:

Elderly dehydrate faster:

• Reduced thirst sensation
• Reduced water reserves
• Multiple medications affect
• Chronic conditions
• Rapid deterioration possible

Emergency signs of dehydration:

• Confusion (new or worse)
• Weakness
• Dizziness
• Low blood pressure
• Rapid heart rate
• Reduced urination
• Falls
• Emergency care

Cognitive assessment:

• Baseline function important
• Watch for changes
• Family observations valuable
• Test cognition periodically
• Consider medication effects

Communication challenges:

• Hearing loss
• Vision problems
• Cognitive decline
• Complex regimens
• Simplify when possible
• Written instructions

Home safety:

• Falls prevention
• Adequate lighting
• Handrails
• Non-slip surfaces
• Regular assistance
• Monitor sedation

Family involvement:

• Understanding medications
• Watching for side effects
• Ensuring adherence
• Communicating with providers
• Emergency contacts

Regular medication review:

• Necessity assessment
• Side effect check
• Interactions
• Adherence
• Simplify when possible
• Deprescribe if appropriate

Non-medication approaches:

• Ginger
• Acupressure
• Small frequent meals
• Hydration
• Rest
• Environmental modifications
• Preferred often in elderly

Special considerations:

Dementia patients:

• May not communicate symptoms
• Watch behavior changes
• Restlessness may indicate nausea
• Reduced eating
• Careful medication selection
• Minimize sedation

Frail elderly:

• Lower doses
• Careful monitoring
• Address hydration priority
• Non-drug approaches
• Family support

Advance care planning:

• Goals of care
• Comfort focus
• Palliative approach
• Address symptoms
• Family involvement

Different antiemetic classes work through different mechanisms, making some more effective for specific causes of nausea.

Class 1: 5-HT3 Antagonists (Serotonin Blockers):

Products:

• Zofran (Ondansetron)
• Granisetron (Kytril)
• Palonosetron (Aloxi)

How they work:

• Block serotonin 5-HT3 receptors
• Both peripheral (GI tract) and central (brain)
• Prevent nausea signal transmission
• Highly effective

Best for:

• Chemotherapy-induced nausea
• Post-operative nausea
• Radiation nausea
• Severe acute nausea

Advantages:

• Minimal sedation
• No cognitive effects
• Not habit-forming
• Multiple forms available

Class 2: Dopamine Antagonists (D2 Blockers):

Products:

• Maxolon (Metoclopramide) - also prokinetic
• Compazine (Prochlorperazine) - phenothiazine
• Haloperidol
• Droperidol
• Domperidone (not on RXshop)

How they work:

• Block D2 dopamine receptors
• Act on chemoreceptor trigger zone
• Some also block other receptors
• Prokinetic effect (metoclopramide)

Best for:

• Migraine-associated nausea
• Gastroparesis (metoclopramide)
• Severe nausea
• Multiple causes

Disadvantages:

• Extrapyramidal side effects
• Tardive dyskinesia risk
• Sedation
• Limited duration of use

Class 3: Antihistamines (H1 Blockers):

Products:

• Dramamine (Dimenhydrinate)
• Meclizine (Antivert, Bonine)
• Promethazine (Phenergan)
• Cyclizine

How they work:

• Block H1 histamine receptors
• Anticholinergic effects
• Act on vestibular system
• Central antiemetic action

Best for:

• Motion sickness
• Vertigo
• Vestibular disorders
• Some pregnancy nausea

Disadvantages:

• Sedation
• Anticholinergic effects
• Not for elderly typically
• Not effective for chemotherapy

Class 4: NK1 Antagonists (Neurokinin-1):

Products (not on RXshop):

• Aprepitant (Emend)
• Fosaprepitant (Emend IV)
• Rolapitant (Varubi)

How they work:

• Block substance P receptors
• Central action
• Newer class

Best for:

• Delayed chemotherapy nausea
• Highly emetogenic chemotherapy
• Post-operative nausea

Class 5: Corticosteroids:

Products:

• Dexamethasone
• Methylprednisolone

How they work:

• Mechanism not fully understood
• Anti-inflammatory action
• Reduces edema
• Central effects

Best for:

• Chemotherapy prophylaxis
• Combined with other antiemetics
• Post-operative

Class 6: Cannabinoids:

Products:

• Dronabinol (Marinol)
• Nabilone (Cesamet)

How they work:

• CB1 receptor activation
• Multiple mechanisms
• Appetite stimulation

Best for:

• Chemotherapy nausea refractory
• Wasting syndrome
• Second-line agent

Class 7: Anticholinergics:

Products:

• Scopolamine (transdermal patch)
• Some antihistamines have effects

How they work:

• Block muscarinic receptors
• Vestibular action
• Central effects

Best for:

• Motion sickness
• Post-operative nausea
• Vestibular disorders

Class 8: Atypical Antipsychotics:

Products:

• Olanzapine (Zyprexa)

How they work:

• Multiple receptor blocks
• D2, 5-HT2, others
• Central effects

Best for:

• Chemotherapy nausea
• Breakthrough nausea
• Emerging role

Combination approaches:

Different mechanisms complement each other:

• Ondansetron + Dexamethasone (chemo)
• Ondansetron + Aprepitant + Dexamethasone (high emetogenic)
• Multi-modal for post-op
• Better outcomes than single agents

Comparing effectiveness by cause:

Choosing right class considers:

• Cause of nausea
• Severity
• Patient factors (age, comorbidities)
• Other medications
• Cost
• Availability
• Prior response

When single class fails:

• Try different class
• Combine classes
• Address underlying cause
• Non-drug approaches

Contact doctor promptly (same day) for:

• Vomiting more than 12 hours
• Signs of dehydration (mild-moderate)
• Blood in vomit small amount
• Persistent nausea multiple days
• Weight loss
• Cannot maintain hydration
• Underlying medical condition worsening
• Concerning associated symptoms

Contact doctor within days for:

• Recurring nausea episodes
• Chronic nausea
• Nausea with medications
• Concerns about side effects of antiemetics
• Ineffective treatment
• Side effects concerning
• Need for dose adjustment
• Questions about long-term use

Antiemetic-specific concerns:

Ondansetron (Zofran) concerns:

• Cardiac symptoms (palpitations, chest pain, fainting)
• Severe headaches
• Signs of allergic reaction
• Severe constipation
• Signs of serotonin syndrome (with other serotonergic drugs)

Metoclopramide (Maxolon) concerns:

• Involuntary movements (face, tongue, limbs)
• Severe restlessness
• Depression, suicidal thoughts
• Movement disorders
• Approaching 12-week limit

Prochlorperazine (Compazine) concerns:

• Muscle spasms or contractions
• Movement disorders
• Severe drowsiness
• Fainting
• Signs of neuroleptic malignant syndrome (fever, muscle rigidity)
• Blood cell changes

Dimenhydrinate (Dramamine) concerns:

• Severe confusion (elderly)
• Cannot urinate
• Vision problems
• Falls
• Cognitive changes

Chronic conditions requiring monitoring:

Chronic gastroparesis:

• Regular follow-up
• Blood sugar control
• Metoclopramide monitoring
• Nutritional support
• Symptom tracking

Cancer treatment:

• Oncology team coordination
• Prophylactic antiemetic plan
• Rescue medications
• Nutrition support
• Address anticipatory nausea

Pregnancy:

• Obstetrician monitoring
• Hyperemesis evaluation
• Nutritional support
• Weight tracking

Chronic migraine:

• Neurologist care
• Preventive strategies
• Migraine and nausea management
• Medication overuse concerns

Post-chemotherapy monitoring:

• Assessment of prophylaxis
• Delayed nausea management
• Nutrition and weight
• Quality of life
• Adjust regimen

Preparing for appointments:

Bring:

• Complete medication list
• Symptom diary
• Recent test results
• Health insurance
• Questions
• Family member if helpful

Track:

• Frequency of nausea/vomiting
• Triggers
• Duration
• Response to medications
• Side effects
• Impact on daily life

Questions to ask:

• What is causing my nausea?
• Which antiemetic is best for me?
• How should I take it?
• What side effects should I watch for?
• When should I call you?
• Are there alternatives?
• How long can I take this?
• Any interactions to worry about?

Long-term follow-up:

Regular reassessment:

• Still needed?
• Lowest effective dose?
• Alternative available?
• Side effects developing?
• Underlying cause addressed?

Underlying cause investigation:

If cause unclear:

• Detailed history
• Physical examination
• Blood tests
• Imaging
• Endoscopy
• Specialist consultation

Warning signs of serious causes:

• Weight loss
• Blood in vomit
• Persistent symptoms
• Neurological signs
• Age over 50 with new nausea
• Progressive worsening
• Requires investigation

Prevention strategies:

• Identify triggers
• Address underlying conditions
• Optimize medications
• Non-drug approaches
• Lifestyle modifications

Emergency vs urgent care:

Emergency room:

• Severe symptoms
• Suspected serious causes
• Cannot manage at home
• After hours

Primary care:

• Non-emergency issues
• Medication management
• Follow-up
• Chronic conditions

Specialist referral:

• Complex causes
• Chronic conditions
• Failed initial treatment
• Gastroenterology
• Neurology (migraine, vertigo)
• Otolaryngology (vertigo)
• Oncology (chemotherapy)
• Endocrinology (metabolic)

Second opinions:

• Complex situations
• Chronic unresolved symptoms
• Multiple failed treatments
• Complementary specialist

Building relationship with doctor:

• Honest communication
• Report all symptoms
• Adherence to treatment
• Follow-up appointments
• Trust and partnership
• Long-term care