[Does medication abuse in patients with chronic migraine influence the effectiveness of preventive treatment with topiramate?].

Introduction: Patients with chronic migraine (CM) and medication abuse are difficult to treat, and have a greater tendency towards chronification and a poorer quality of life than those with other types of headache.

Aim: To evaluate whether the presence of medication abuse lowers the effectiveness of topiramate.

Patients And Methods: A series of patients with CM were grouped according to whether they met abuse criteria or not. They were advised to stop taking the drug that they were abusing. Treatment was adjusted to match their crises and preventive treatment with topiramate was established from the beginning. The number of days with headache and intense migraine in the previous month and at four months of treatment was evaluated.

Results: In all, 262 patients with CM criteria were selected and 167 (63.7%) of them fulfilled abuse criteria. In both groups there was a significant reduction in the number of days with headache/month and number of migraine attacks/month at the fourth month of treatment with topiramate. The percentage of reduction in the number of days with headache/month in CM without abuse was 59.3 ± 36.1%, and with abuse, 48.7 ± 41.7% (p = 0.0574). The percentage of reduction in the number of days with intense migraine/month in CM without abuse was 61.2%, and with abuse, 50% (p = 0.0224). Response rate according to the number of days with headache/month in CM without abuse was 69%, and with abuse, 57%. Response rate according to the number of intense migraines/month in CM without abuse was 76.8%, and in CM with abuse, 61% (p = 0.0097).

Conclusions: Topiramate was effective in patients with CM with and without medication abuse, although effectiveness is lower in the latter case.