Does the antimigraine action of flunarizine involve the dopaminergic system? A clinical-neuroendocrinological study

We have investigated the prolactin response to bromocriptine (BRC), a D2 do pamine receptor agonist in migrainous women before and after treatment with flunarizine. We evaluated whether this test was predictive of therapeutic efficacy of flunarizine treatment and whether the therapeutic response to f lunarizine treatment was related to its effect on dopaminergic system at tu beroinfundibular level. Ten migrainous women underwent a BRC test in the la te follicular phase before and after 1 and 3 months of treatment with fluna rizine 10 mg at bedtime. Blood samples of prolactin (PRL), growth hormone, follicle stimulating hormone, luteinizing hormone, estradiol and progestero ne were taken at basal condition. PRL was also evaluated 1 and 2 h after BR C (2.5 mg) administration. Each patient kept a daily headache diary for 1 m onth prior to the test and throughout the study. The level of PRL inhibitio n after BRC administration, observed before flunarizine treatment, was not predictive of the therapeutic response observed after 1 and 3 months of tre atment. The effect of flunarizine on PRL level was not related to the thera peutic efficacy of the drug. These data suggest that flunarizine does not a ttenuate the activity of dopaminergic neurons in migrainous patients, and t hat the antimigraine effect of flunarizine does not seem related to its act ion on dopaminergic system at least at tuberoinfundibular level.