Objectives.– To document the relationship between the 5-HT receptor agonist sumatriptan and a change in the nature of cluster headache in four cases. To relate the findings to the literature on the use of sumatriptan in both cluster headache and migraine.
Background.– Studies of the efficacy and adverse effects of long-term treatment with sumatriptan in cluster headache are limited and report conflicting findings.
Methods.– Four cases are described.
Results.– All four patients developed a marked increase in the frequency of attacks 3 to 4 weeks after initiating treatment with the drug for the first time. Three patients also developed a change in headache character, and 2 experienced prolongation of the cluster headache period. Withdrawal of the drug reduced the frequency of headaches and eliminated the newly developed type of headache.
Conclusions.– Determination of the effects of long-term use of sumatriptan will result in more precise guidelines for the frequency and duration of treatment with this otherwise extremely beneficial drug.