Traitement médicamenteux de fond de la migraine

Prophylactic treatment is mainly intended to reduce the frequency of migraine attacks. Based on the results of published controlled trials, the main prophylactic drugs are some beta-blockers, methysergide, pizotifene, oxetorone, flunarizine, amitriptyline, NSAIDs, sodium valproate and topiramate. With these drugs, the frequency of attacks can be reduced by half in 50 percent of patients. Some less evaluated substances such as aspirin, DHE, indoramine, and angiotensin II inhibitors may be useful. The decision to treat with drugs and the choice of a prophylactic drug are made together with the patient. The superiority of one major drug over another has never been demonstrated in a comparative trial, thus the choice of the drug to start with depends on the possible side effects and contraindications, the characteristics of the migraine attacks, and the associated morbidities and possible interactions with abortive medications. Doses should be increased gradually, in order to reach the recommended daily dose, only if tolerance permits. Treatment efficacy has to be assessed after 2 or 3 months, and in case of failure or poor tolerance, another treatment should be started. If the treatment is successful, it should be continued for 6 to 12 months, and then tapered off. The moderate efficacy and the frequency of the side effects observed with prophylactic drugs explain the high rate of withdrawals. Some patients nevertheless dramatically improve, warranting trying several drugs successively in order to find the most appropriate one.