Antiemetics
which antiemetic?
- post-op / opioid-induced / general → ondansetron first line
- vestibular / motion / vertigo → cyclizine or prochlorperazine
- gastroparesis / functional → metoclopramide (max 5 days)
- palliative / refractory → haloperidol (low dose) or levomepromazine
- bowel obstruction → cyclizine or haloperidol (avoid prokinetics: metoclopramide, domperidone)
cautions by patient
- Parkinson’s / Lewy body → avoid metoclopramide, domperidone, haloperidol, prochlorperazine (all worsen EPS or psychosis). Use ondansetron.
- QT prolongation → check ECG before ondansetron (IV max 16 mg/day), domperidone, or haloperidol
- liver disease → domperidone contraindicated in moderate/severe hepatic impairment (Child-Pugh B/C)
- ondansetron: max 8 mg/day
- haloperidol: halve the initial dose
- metoclopramide: reduce by 50% in severe impairment
- renal impairment → metoclopramide: reduce dose (renally cleared)
- young adults → metoclopramide, prochlorperazine: higher EPS/dystonia risk
| Generic | Brand | Route | Dose | Notes |
|---|---|---|---|---|
| Ondansetron | Zofran, Danset | PO / IV | 4–8 mg up to TDS | QT caution; max 16 mg/day IV |
| Metoclopramide | Primperan | PO / IV | 10 mg TDS | Prokinetic; max 5 days; EPS risk (avoid in young/Parkinson’s); renally cleared, adjust to CrCl |
| Domperidone | Motilium | PO | 10 mg TDS | QT caution |
| Cyclizine | Valoid | PO / IV / IM | 50 mg TDS | Vestibular / mechanical nausea |
| Prochlorperazine | Stemetil | PO / IM | 5 mg PO / 12.5 mg IM | Vertigo-associated nausea |
| Promethazine | Phenergan | PO / IM | 25 mg | Sedating |
| Haloperidol | Haldol | PO / IV / SC | 0.5–1 mg | Refractory / palliative; ECG first, QT |
Laxatives & bowel regimen
| Generic | Brand | Route | Dose | Notes |
|---|---|---|---|---|
| Lactulose | Duphalac | PO | 15–30 mL OD–BD | Osmotic; titrate to effect |
| Macrogol / PEG | Movicol, Forlax | PO | 1 sachet OD–TDS | Osmotic |
| Bisacodyl | Dulcolax | PO / PR | 5–10 mg PO / 10 mg PR | Stimulant |
| Glycerin suppository | – | PR | 1 PRN | Rectal |
| Phosphate enema | Fleet | PR | 1 PRN | Rescue; caution in renal impairment |
Proton pump inhibitors
| Generic | Brand | Route | Dose (PO) | Dose (IV) | Renal adjust |
|---|---|---|---|---|---|
| Omeprazole | Losec, Minisec | PO / IV | 20–40 mg OD | 40 mg IV OD | No |
| Pantoprazole | Proton | PO / IV | 40 mg OD | 40 mg IV OD | No |
| Esomeprazole | Nexium | PO / IV | 20–40 mg OD | 40 mg IV OD | No |
| Dexlansoprazole | Dexilant | PO only | 30–60 mg OD | – | No |
PPI only with an indication → previous GI bleed or ulcer; anticoagulant plus antiplatelet, dual antiplatelet, or either with an NSAID or steroid; ICU, ventilated or coagulopathic. Not routine for everyone else. IV only if not tolerating PO.
Educational reference for clinicians. Doses are typical adult starting points. Cross-check allergies, interactions, current local policy, the formulary, and renal/hepatic function before prescribing.
Last updated · October 2026