Clinical ergotism with lingual ischemia induced by clarithromycin-ergotamine interaction

The macrolide class of antibiotics, including erythromycin and troleandomycin, is associated with clinically significant adverse drug interactions. This results from macrolide inhibition of cytochrome P-450 metabolism of numerous xenobiotics, resulting in elevated serum drug levels and clinical intoxication. Animal studies, however, suggest that clarithromycin, the newest approved macrolide antibiotic, has has less potential for adverse drug reactions. We describe a patient who, on her fifth day of clarithromycin therapy, developed clinical ergotism (i.e., hypertension, lingual ischemia, and peripheral cyanosis) several hours after administration of her usual 2-mg dose of ergotamine tartrate. To our knowledge, this is the first report of clinical ergotism precipitated by clarithromycin-ergotamine interaction and suggests that, like other macrolide antibiotics, ergot preparations should be avoided in patients who are taking clarithromycin.