Alteration in Nature of Cluster Headache During Subcutaneous Administration of Sumatriptan

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.