Prolactin response to bromocriptine in flunarizine-treated migrainous women

Flunarizine, a calcium channel blocker, is widely used in migraine prophylaxis. Although an antidopaminergic effect has been suggested for this drug, it is unclear whether the antimigraine action of flunarizine involves the dopaminergic system. We studied the inhibitory response of prolactin to acute administration of bromocriptine, a D2 dopamine receptor agonist, before and after 1 month of treatment with flunarizine in migrainous women. Flunarizine treatment increased basal prolactin levels, but it did not reduce the inhibitory response of prolactin to acute bromocriptine administration. These findings do not support the hypothesis that flunarizine acts as a direct antagonist at the D2 dopamine receptor.