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Antihistamine Antiemetic — Hyperemesis Gravidarum

Cyclizine (Nausea and Vomiting in Pregnancy)

Brand names: Valoid

This monograph covers cyclizine for nausea and vomiting in pregnancy, where this sedating antihistamine antiemetic is a recognised first-line option, including for hyperemesis gravidarum.

Dosing — not shown for this use

The product information we hold does not support a dose for this page's specific use, route or population, so none is shown. Follow your local or national guideline, and confirm against the product SmPC.

The licensed dosing — for the medicine's licensed uses, which may differ from this page's — is on Cyclizine.

Clinical monograph

How it works

Cyclizine is an H1-antihistamine with antimuscarinic activity that acts on the vomiting centre and vestibular pathways to suppress nausea and vomiting.

Prescribing in practice

  • Cyclizine is considered safe and is recommended among first-line antiemetics for nausea and vomiting in pregnancy, so it can be used when non-pharmacological measures are insufficient.
  • It causes drowsiness and antimuscarinic effects such as dry mouth, blurred vision and constipation.
  • Rapid intravenous administration can cause unpleasant transient effects and is associated with potential for misuse.

Monitoring

Assess control of symptoms, hydration status and ketosis in significant vomiting, and review for excessive sedation or antimuscarinic effects.

Counselling the patient

  • The medicine may make you drowsy; avoid driving if affected.
  • Combine with rest, small frequent meals and fluids.
  • Seek review if you cannot keep fluids down or pass little urine.

Evidence & guidelines

UK guidance, including from the Royal College of Obstetricians and Gynaecologists, includes cyclizine among first-line antiemetics for nausea and vomiting of pregnancy and hyperemesis gravidarum.

Reference: RCOG Green-top 69 (Hyperemesis Gravidarum 2024); NICE NG201; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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