Treatment patterns and Reasons for Discontinuing Preventive Treatment in Cluster Headache: A prospective cohort study.

BackgroundPharmacological prevention of cluster headache aims to reduce the frequency and intensity of attacks, but the long-term effect and tolerance of treatments remain uncertain. The aim of the study was twofold. First, to quantify the discontinuation rates of preventive treatment due to side effects; and second, to assess the proportion of verapamil responders who maintained preventive effectiveness at follow-up.MethodsIn total, 596 participants with cluster headache fulfilling the ICHD-criteria (the baseline cohort) completed a semi-structured interview between 2017 and 2023. Of these, 430 were re-interviewed after a median time of 4.6 years constituting the follow-up cohort.ResultsIn the baseline cohort, 457 participants (76.7%) had taken a preventive medicine for cluster headache. Among these, 123 (26.9%) had discontinued a treatment due to intolerable side effects. The discontinuation rate for the first-line treatment verapamil was 18%, whereas the second-line treatments with lithium or topiramate had been discontinued in nearly half. The odds of discontinuing due to intolerable side effects of lithium or topiramate therapy were four times higher than for verapamil (p < 0.0001).In the follow-up cohort, only 143 participants (33.3%) still received a preventive treatment at the time of the second interview. Of the initial 182 verapamil users, 77 (42.3%) continued, 54 (29.7%) had discontinued due to remission, and 51 (28%) discontinued due to intolerable side effects, lack of effect, or for other reasons. At follow-up including new users, a total of 91 participants were treated with verapamil and 50 of them (54.9%) were 50% responders.ConclusionEffective therapeutic prevention of cluster headache is hindered by intolerance and insufficient efficacy of the available preventives. Though verapamil remains effective over time for initial responders, there is a high rate of discontinuation due to side effects or lack of efficacy. Taken together with the low proportion of 50% responders, the findings underscore the need for new tolerable and effective preventive treatment for cluster headache.