Migraine prophylaxis with calcium antagonists: A haemodynamic study using transcranial Doppler ultrasound

Introduction. Despite its widespread use, a good explanation for the mechanism of action of calcium antagonists (CA) in the prophylaxis of migraine has still not been proposed Aims. To determine whether nicardipine and flunarizine therapy is capable of inducing changes in the brain haemodynamics of migraine sufferers that lend support to a vascular mechanism of action for these drugs, as evaluated by transcranial Doppler ultrasound (TCD). Patients and methods. We present a prospective, descriptive study based on observation conducted in a Neurology outpatients department. Patients between the ages of 16 and 50 with migraine (following IHS criteria) who were being treated with nicardipine and flunarizine as a prophylactic measure and did not fulfil any of the exclusion criteria were selected consecutively. The TCD study was performed before and during treatment with CA (flunarizine or nicardipine), for a minimum of one month. The following haemodynamic variables were determined: mean speed, Gosling's pulsatility index and cerebrovascular reserve, determined by the breath-holding index. Pre and post-prophylaxis variables were compared using the Wilcoxon signed rank test. Results. Eight patients with migraine were included in the study and no significant differences in any of the three haemodynamic variables were observed between the values obtained prior to or during treatment. Conclusions. The absence of haemodynamic changes in TCD does not lend support to a vascular mechanism of action for CA in migraine.