Cinnarizine

How it works

It is an H1-antihistamine that also has calcium-channel-blocking activity in the vestibular system, damping the response to vestibular stimulation; central antihistaminic and antidopaminergic actions contribute to both its antiemetic effect and its adverse effects.

Prescribing in practice

• It can cause or worsen extrapyramidal symptoms and parkinsonism, particularly in older people, so avoid prolonged use in the elderly and review for new movement disorders.
• It commonly causes drowsiness, which is additive with alcohol and other sedatives and may impair driving and skilled tasks.
• Anticholinergic effects (such as dry mouth, blurred vision and urinary hesitancy) can occur; use caution where these would be hazardous.

Monitoring

No routine laboratory monitoring is required; on continued use, review for excessive sedation and for parkinsonian or other extrapyramidal features, especially in older patients.

Counselling the patient

• It can make you drowsy — avoid alcohol and do not drive or operate machinery until you know how it affects you.
• For motion sickness, take it before travelling.
• Report any tremor, stiffness, slowness of movement or restlessness, particularly with longer-term use.

Evidence & guidelines

An established option for vestibular symptoms and motion sickness; in older people the risk of drug-induced parkinsonism favours short-term use and alternatives where possible.