Steady-state serum quinidine concentration: role in prophylactic therapy following acute myocardial infarction.
Steady-state serum quinidine concentrations were monitored in 24 patients with acute myocardial infarction who were on a 1,300-mg daily dosing regimen. Mean serum concentrations spanned the therapeutic range, from 2 to 6 microgram/ml in 21 patients. In no patient was the level of 7 microgram/ml exceeded. Mean levels were similar in patients with congestive heart failure [3.6 +/- 1.5 (SD) microgram/ml] as in those free of failure (3.2 +/- 1.3 microgram/ml), and did not vary with impairment of renal function. There was a significant correlation between mean individual serum quinidine concentrations and the rate-normalized QT interval prolongation (r = 0.54, P less than 0.01); however, variability of the response was high. Variability of the mean serum quinidine levels among individuals was 41%. Variability within individual patients was only 18%. In the individual patient receiving prophylactic oral quinidine therapy, monitoring serum quinidine levels appears to be an accurate, reproducible and pharmacologically significant guideline to therapy.
D000328:Adult; D000368:Aged; D001145:Arrhythmias, Cardiac / Q000097:blood / Q000517:prevention & control*; D004305:Dose-Response Relationship, Drug; D004562:Electrocardiography; D005260:Female; D006333:Heart Failure / Q000097:blood; D006352:Heart Ventricles; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood / Q000188:drug therapy*; D011802:Quinidine / Q000097:blood / Q000627:therapeutic use*
D011802:Quinidine