Drug Interactions

The ephedra alkaloids are all sympathomimetic amines, which means that a host of drug interactions are theoretically possible. In fact, only a handful of adverse drug interactions have been reported in the peer-reviewed literature. The most important of these involve the monoamine oxidase inhibitors (MAOI). Irreversible, nonselective MAOIs have been reported to adversely interact with indirectly acting sympathomimetic amines present in many cough and cold medicine. In controlled trials with individuals taking moclobemide, ephedrine's effects on pulse and blood pressure were potentiated, but only at higher doses than those currently provided in health supplements (137). Ephe-drine-MAOI interaction may, on occasion, be severe enough to mimic pheo-

chromocytoma (138). In addition, there is decreased metabolic clearance of pseudoephedrine when MAOIs are administered concurrently (139). At least one case report suggests that selective serotonin reuptake inhibitor antide-pressants can react with pseudoephedrine, leading to the occurrence of "serotonin syndrome" (140). Bromocriptine, the ergot-derived dopamine agonist can interact with pseudoephedrine, and would presumably interact with ephe-drine as well (141). Surgical patients being treated with clonidine have an enhanced pressor response to ephedrine, apparently a result of clonidine-induced potentiation of aradrenoceptor-mediated vasoconstriction (142,143). In some clinical trials, the coadministration of ephedrine with morphine has been shown to increase analgesia (144), but this approach to pain relief remains somewhat controversial.

0 0

Post a comment