Subcutaneous Sumatriptan Injection for the Acute Treatment of Migraine
abstract & commentary
Source: O’Quinn S, et al. Prospective large-scale study of the tolerability of subcutaneous sumatriptan injection for the acute treatment of migraine. Cephalalgia 1999;19:223-231.
The new 5-ht 1d/1b agonists have revolutionized the treatment of migraine. The mechanism of action appears to be both the inhibition of neurogenic inflammation by binding to presynaptic 1D receptors on trigeminal afferents and vasoconstriction through action at the post-synaptic 1B receptors on cerebral blood vessels. Sumatriptan has been the prototype of the class and the only one available in parental formulations. Initial enthusiasm for the drug was tempered by sporadic reports of serious cardiac complications. The coronary arteries also contain 1B receptors and there has been both theoretical and clinical concern about triptan- induced coronary artery vasospasm. O’Quinn and colleagues have succeeded in putting the serious risks from triptans in perspective.
The present study described a multicentered, prospective, uncontrolled, open-labeled design looking at serious adverse events associated with sumatriptan injection. There were 12,339 migraineurs followed for one year under usual practice parameters. There were 86% women, the mean age was 40.9 years, and the total number of headaches treated was 185,569 with a mean of 15 attacks per patient. Twenty-five deaths occurred but none of the causes was attributable to sumatriptan. There were six fatal cardiac and cerebrovascular events remote from sumatriptan use. Four patients had strokes and three reported TIAs. Of these, only two had events within 24 hours of using sumatriptan. None was left with a serious disability. Furthermore, O’Quinn et al noted that this incidence of stroke matches the expected incidence of stroke in this population. Thirty-six patients had noncardiac events. Three myocardial infarctions occurred at least three days remote from the use of sumatriptan. In the six reports of angina, one occurred within 24 hours of using sumatriptan. Sixteen patients were noted to have minor arrhythmias, such as palpitations, and tachycardia within 24 hours of using sumatriptan. O’Quinn et al conclude that sumatriptan injection is safe for large numbers of patients under usual practice guidelines according to labeled instructions.
This large-scale study is important for several reasons. It provides us an accurate assessment of triptan safety. Since the sumatriptan injection is the most potent dosage, it is easy to extrapolate to the other triptans as well. When sensible practice guidelines are followed and patients most at risk for coronary vascular disease are screened, the triptans prove to be a safe medication. Despite their impact, the triptans as a class occupy only about 30% of prescribed migraine drugs. Despite the fact that usual pain medications do not treat migraine well, Tylenol with codeine and other analgesics remain the number one prescribed migraine remedy. Neurology Alert thinks this study should convince more practitioners that safe and effective alternatives exist for their migraine patients who have not yet tried one of the new 5-HT 1D/1B agonists. —jr