Aitio M L, Vuorenmaa T
Br J Clin Pharmacol. 1980 Feb;9(2):149-52. doi: 10.1111/j.1365-2125.1980.tb05825.x.
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.