The effect of an antiserotonin agent pizotifen on platelet aggregability in migraine patients.

In 19 patients who were suffering from frequent migraine attacks and were treated with pizotifen, spontaneous platelet aggregation (SPA) was measured prior to treatment and at the second, fourth and sixth month of treatment. A Migraine Headache Score (MHS) was employed for evaluation of the "activity" of migraine in the same periods. Spontaneous platelet aggregation was also measured in a control group of 40 migraine-free subjects. Prior to treatment the mean value of SPA in the group of migraine patients was four times higher than in the control group. In the 19 migraine patients the mean value of SPA in the second month of treatment showed a 48% reduction when compared with the mean value of SPA prior to treatment. Clear clinical improvement was observed during the treatment, and the average MHS in the second month of treatment showed a 77% reduction compared with the average MHS prior to treatment. The increased rate of SPA prior to treatment and the close correlation between the SPA rate and "activity" of migraine during the treatment suggest that increased platelet aggregability may play a significant role in the pathogenesis of migraine.