Renal infarction during the use of rizatriptan and zolmitriptan: two case reports.

Rizatriptan and zolmitriptan are both used to relieve acute migraine and cluster headaches. The mechanism of action is similar to the other triptans, in that they reverse abnormal cerebral vasodilation through their activity as 5-HT1B receptor agonists. Triptan-induced vasoconstriction is attributed to its activity on peripheral 5-HT1B receptors and has rarely been reported to result in stroke, myocardial infarction and ischemic colitis. We present two cases of renal infarction associated with therapeutic triptan use. The first patient is a 57-year-old man with a history of hypertension that was well controlled on valsartan and hydrochlorothiazide. He was recently diagnosed with cluster headaches and was treated with indomethacin, prednisone, butalbital-acetaminophen-caffeine and hydrocodone without relief. He then received two therapeutic doses of rizatriptan on each of the two days prior to presentation. Subsequently, he presented to the emergency department complaining of nausea, vomiting and right-sided abdominal pain. A computerized tomography (CT) scan of the abdomen and pelvis with intravenous contrast revealed a very large wedge shaped infarction of the right kidney. The second patient is a 34-year-old man with a past medical history significant only for life-long migraine headaches successfully treated for the past six years with zolmitriptan. Shortly after taking one therapeutic dose of zolmitriptan, he presented to the emergency department complaining of nausea and left-sided abdominal pain. A CT scan of the abdomen and pelvis with intravenous contrast revealed multiple wedge-shaped infarctions of the left kidney. Renal infarction was confirmed in both patients by arteriogram of the renal arteries. Although both rizatriptan and zolmitriptan are effective in the treatment of migraine and cluster headaches, they may induce peripheral vasospasm leading to renal infarction.