Flunarizine is a drug classified as a calcium channel blocker. Flunarizine is a non-selective calcium entry blocker with other actions including histamine H1 receptor blocking activity. It is effective in the prophylaxis of migraine, occlusive peripheral vascular disease, vertigo of central and peripheral origin, and as an adjuvant in the therapy of epilepsy. It may help to reduce the severity and duration of attacks of paralysis associated with the more serious form of alternating hemiplegia, as well as being effective in rapid onset dystonia-parkinsonism (RDP). Both these conditions share a mutation in the ATP13A gene; flunarizine is not available by prescription in the U.S. or Japan. Flunarizine has been shown to significantly reduce headache frequency and severity in both adults and children. Flunarizine was discovered at Janssen Pharmaceutica in 1968.
Flunarizine has some side effects including weight gain, extrapyramidal effects, drowsiness and depression, it is contraindicated in hypotension, heart failure and arrhythmia. Flunarizine use is avoided in patients with depression, severe constipation or those with extrapyramidal disorders.