Daily long-term use of sumatriptan injections in cluster headaches

My most commented on blog post (over 150 comments) is on the daily use of triptans. A new report confirms the safety of long-term daily use of sumatriptan injections in cluster patients. Cluster headaches are arguably the most severe type of headaches and the name comes from the fact that they tend to occur in clusters lasting several weeks to several months. However, in some patients headaches become persistent without any remissions and then they are called chronic cluster headaches. The only FDA approved treatment for cluster headaches is injectable sumatriptan (Imitrex). Most patients have one cluster attack in 24 hours, but some have many. A report mentioned in one of my other previous blogs describes a woman (although men are more commonly affected by cluster headaches) who has been injecting sumatriptan daily on average 20 times a day for 15 years.

A recent report by Massimo Leone and Alberto Cecchini is entitled, Long-term use of daily sumatriptan injections in severe drug-resistant chronic cluster headache.

The authors investigated occurrence of serious side effects in patients with chronic cluster headaches who were using sumatriptan injections continuously at least twice daily (the official limit) for at least 2 years. They found fifty three such patients with chronic cluster headaches seen in their clinic between 2003 and 2014. During the 2-year period, all patients were carefully followed with regular visits at their center. Headaches and sumatriptan consumption were recorded in headache diaries. Patients were questioned at each visit about serious side effects and had at least two electrocardiograms. Brain MRI was normal in all patients. None of the patients had a history of stroke, TIA, ischemic heart disease, myocardial infarction, or arrhythmia, or diseases affecting systemic vessels.

In the 2-year study period, no serious side effects were observed and no patients needed to discontinue sumatriptan use. No electrocardiogram abnormalities were found. All patients needed a full dose (6 mg) of sumatriptan injection (prefilled syringes with 4 and 6 mg available). At the end of the study period, 42% noticed some reduction in the efficacy of sumatriptan injections both in terms of time of onset of effect and on pain intensity, but still considered the drug their first choice to treat the attacks.

In the study period, 36 of the 52 patients (69%) used more than 12 mg of sumatriptan in 24 hours (maximum 36 mg in 24 hours) but no increase in number or severity of side effects was observed during the course of the study. Complete loss of efficacy was not reported by any of the patients.

The authors mention that since the launch of sumatriptan injections in 1992 and until 1998, approximately 451 serious cardiac side effects have been reported to occur within 24 hours after administration of sumatriptan injections, tablets or nasal spray, but this is out of more than 236 million migraine attacks and more than 9 million patient exposures between 1992 and 1998. The majority of patients who developed serious cardiac events within 1 to 3 hours of sumatriptan administration had risk factors for coronary artery disease.

The authors concluded that their results showed that long-term daily sumatriptan use in patients free of heart disease did not cause serious side effects and this is in line with observations from previous studies.