Enhanced metabolism and diminished efficacy of disopyramide by enzyme induction?
1 Monitoring plasma levels of mono-N-dealkyldisopyramide (MND), the most important metabolite of disopyramide, has been considered unnecessary. 2 We measured plasma levels of both disopyramide and MND in 64 consecutive patients receiving long term oral therapy with disopyramide. 3 Six patients were found with high plasma levels of MND, and simultaneously low levels of disopyramide. 4 Three of these patients were taking simultaneously phenytoin. The other three had a relatively high dose of disopyramide with regard to their renal function. One patient had terminal uremia, three had less severe renal dysfunction. 5 The underlying mechanism and clinical significance of the findings are discussed.
D000368:Aged; D003401:Creatine / Q000097:blood; D004206:Disopyramide / Q000378:metabolism / Q000494:pharmacology*; D004347:Drug Interactions; D004790:Enzyme Induction / Q000187:drug effects*; D005260:Female; D006801:Humans; D008658:Inactivation, Metabolic; D008297:Male; D008875:Middle Aged; D010672:Phenytoin / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology*
D011725:Pyridines; D010672:Phenytoin; D004206:Disopyramide; D003401:Creatine