Cerebral antivasoconstrictive effects of flunarizine.

Flunarizine is a selective Ca++-antagonist with weaker H1-histaminergic antagonistic properties. Flunarizine reduces vasospasm caused by an exaggerated Ca++-influx in depolarized arteries and by vasoactive substances released from aggregating platelets. This Ca++-antagonist also antagonizes the mutual amplification of the vasoconstrictor action of the platelet products. Flunarizine is particularly effective in the cerebral blood vessels, also when they are hyperreactive because of hypoxia. The compound does not interfere with normal arteriolar autoregulation or heart function. Thus flunarizine may be particularly effective in preventing vasospasm without lowering blood pressure or inducing a steal phenomenon.