Cluster headache not responsive to sumatriptan: A retrospective study

Introduction: Subcutaneous sumatriptan, a 5HT(1B/1D) agonist, is the most effective drug in cluster headache acute treatment. About 25% of the patients do not respond to subcutaneous sumatriptan; the reasons for this are unknown. In this study, we compare clinical characteristics of cluster headache patients responding and non-responding to subcutaneous sumatriptan. Methods: We retrospectively investigated the clinical records of 277 cluster headache patients. Patients reporting repeated satisfactory response to subcutaneous sumatriptan within 15 minutes were considered responders. Results: Of 206 cluster headache patients who had used subcutaneous sumatriptan (mean age 45.6, 16% females, 48% chronic), 91% were responders, and 9% non-responders. Compared to responders, non-responders had longer and more frequent attacks: 60 (median; IQR 38-90) vs. 100 (60-120) minutes (p = 0.028), 4 (2.5-5) vs. 3 (2-4) attacks/day (p = 0.024). No other difference was found. Conclusions: In cluster headache attacks with long duration and high frequency, pain mechanisms not involving 5HT(1B/1D) receptors may play a more relevant role.

Automated summary

In cluster headache patients with long and frequent attacks, those who do not respond to subcutaneous sumatriptan have longer duration and more frequent attacks compared to responders.