Overview
Cinnarizine is a piperazine derivative with antihistaminic, antiemetic, and calcium channel blocking properties. It is primarily used for vestibular disorders like vertigo and motion sickness, and peripherally for circulatory disorders. It acts by inhibiting calcium influx in vascular smooth muscle and labyrinthine cells, reducing vasoconstriction and vestibular stimulation.
Mechanism of Action
Acts as a selective calcium channel blocker (L-type) in vascular smooth muscle and labyrinthine cells, reducing calcium influx. Also has antihistaminic (H1 receptor antagonist) and mild anticholinergic effects, contributing to its anti-vertigo and antiemetic actions.
Indications
- Vertigo (including Ménière's disease, vestibular disorders)
- Motion sickness prevention and treatment
- Peripheral vascular disorders (e.g., intermittent claudication, Raynaud's phenomenon)
Dosage
Adults: For vertigo - 25 mg three times daily. For motion sickness - 30 mg 2 hours before travel, then 15 mg every 8 hours during journey. Maximum daily dose: 225 mg. Elderly: Lower doses may be required. Pediatric use not well established.
Contraindications
- Hypersensitivity to cinnarizine or piperazine derivatives
- Parkinson's disease or extrapyramidal disorders
- Severe liver impairment
- Porphyria
Side Effects
- Drowsiness, fatigue
- Dry mouth
- Weight gain
- Headache
- Gastrointestinal disturbances
- Extrapyramidal symptoms (tremor, rigidity)
- Depression
- Skin reactions
Interactions
- CNS depressants (alcohol, benzodiazepines, opioids) - enhanced sedation
- Antihypertensives - additive hypotensive effects
- Anticholinergic drugs - increased anticholinergic effects
- Levodopa - reduced efficacy in Parkinson's disease