Quinidine Elimination in Patients with Congestive Heart Failure or Poor Renal Function

Abstract

Abstract Plasma quinidine half-life values, determined by a relatively specific double extraction method in eight patients with poor renal function, eight with congestive heart failure, and nine controls were similar for all groups. When quinidine was measured by a nonspecific fluorescent method, the half-life values calculated for the uremic patients were longer than those for the controls. The nonspecific method does not differentiate slow biotransformation of quinidine from normal biotransformation but slow excretion of metabolites. Steady-state plasma quinidine concentrations were measured in 14 patients treated for arrhythmias and 12 with congestive heart failure. Therapeutic effectiveness was associated with concentrations of 2.3 to 5.0 μg per milliliter and ineffectiveness with lower levels or complicating illnesses. The relation of dose to steady-state blood level was similar for the two groups. Quinidine elimination appears to be grossly normal in patients with congestive heart failure or poor re...