First-lineValoid
Cyclizine
H1-antihistamine antiemetic
Workhorse antiemetic for hyperemesis.
OralIMIV
First-line for
- Nausea & vomiting of pregnancy
- Hyperemesis gravidarum (step 2)
Mechanism
H1 antagonism + anticholinergic at vomiting centre.
Cyclizine
- 50 mg TDS — give slow IV (tachycardia)
Dosing
- Dose
- 50 mg PO/IM/slow IV TDS
Contraindications
- CautionSevere heart failure (anticholinergic load)
Side effects
- Drowsiness, dry mouth
- Tachycardia (rapid IV)
Fetal & maternal notes
- • Extensive use — considered safe all trimesters & BF.
Key interactions
CNS depressants
Caution↑ sedation
Clinical pearls
- 💡 Combine with PPI if reflux.
- 💡 Switch if QT concern.
Content last reviewed: REPLACE_ME (e.g. 2026-07)
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