Antihistamine Antiemetic Pregnancy: In the absence of definitive human data, use in pregnancy is not advised. Breast-feeding: cyclizine is excreted in human milk (amount not quantified).

Cyclizine

Brand names: Valoid

Cyclizine is an antihistamine antiemetic used for nausea and vomiting of various causes, including motion sickness and post-operative nausea.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 50 mg

Route: Oral

Frequency: May be repeated up to three times a day

ELDERLY: there have been no specific studies of cyclizine hydrochloride in the elderly; experience has indicated that normal adult dosage is appropriate. To prevent motion sickness, cyclizine should be taken about one to two hours before departure. Children 6-12 years: 25 mg orally, up to three times a day. Children over 12 years: 50 mg orally, up to three times a day. Not recommended for children under 6 years.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to the active substance or to any excipient
Acute alcohol intoxication (the anti-emetic properties of cyclizine may increase the toxicity of alcohol)

Side effects

Somnolence / drowsiness
Dry mouth, nose and throat
Constipation
Blurred vision
Tachycardia / palpitations

Interactions

Alcohol and other CNS depressants (additive effects: hypnotics, tranquillisers, anaesthetics, antipsychotics, barbiturates)
Pethidine (cyclizine enhances its soporific effect)
Opioid analgesics (cyclizine may counteract their haemodynamic benefits)
Other anticholinergic/antimuscarinic drugs (e.g. atropine, tricyclic antidepressants and MAOIs) — additive antimuscarinic effects
Ototoxic drugs such as aminoglycoside antibacterials (cyclizine may mask warning signs of ototoxic damage)

Clinical monograph

How it works

It is an H1-antihistamine with antimuscarinic activity that reduces nausea via central pathways.

Prescribing in practice

Antimuscarinic effects (dry mouth, blurred vision, urinary retention, confusion) are a concern in older patients.
It can cause tachycardia and is generally avoided in severe heart failure; rapid intravenous injection can be unpleasant.
It has some misuse potential, particularly with opioids.

Monitoring

Review the antiemetic benefit and anticholinergic effects.

Counselling the patient

It can cause drowsiness and a dry mouth.
Take care driving until you know how it affects you.

Evidence & guidelines

A commonly used antiemetic, with caution about anticholinergic effects in older patients and in heart failure.

Reference: STOPP/START v3; AGS Beers Criteria 2023; Palliative Care Formulary; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways