variations in cytochrome P450 (CYP)-catalyzed drug metabolism, and that these variations sometimes lead to different susceptibilities of humans to the pharmacological and toxicological actions of drugs, toxic chemicals, and carcinogens. For example, there are large interindividual differences in the expression levels and catalytic activities of CYP enzymes in human liver. Additionally, multiple...

the effect of different kinds of surfactants in various concentrations incorporated in an inert matrix, on the release of procainamide hydrochloride, as a cationic model compound, was investigated in this study. sodium lauryl sulfate and sodium stearate as anionic surfactants, cetyl pyridinium chloride and cetyltrimethyl ammonium bromide as cationic and span 60 and tween 80 as non-ionic surfact...

BACKGROUND Antiarrhythmic drugs are known to have state-dependent interactions with cardiac sodium channels, and these have potentially important implications for drug effects on cardiac conduction, particularly in situations of changed resting potential and heart rate. Recent advances in theoretical approaches permit beat-to-beat changes in sodium channel block to be inferred from conduction c...

Many of the newer antiarrhythmic agents are said to cause minimal myocardial depression, but their hemodynamic effects have not been invasively evaluated and compared in patients with severe chronic heart failure. In a randomized, crossover study, the hemodynamic responses to single oral doses of procainamide (750 mg), tocainide (600 mg), and encainide (50 mg) given to 21 patients with severe c...

We describe a modified colorimetric method for determining procainamide in plasma by use of a diazotization and coupling reaction with N-(1-naphthyl)-ethylenediamine dihydrochloride (Marshall's reagent). The sensitivity of the assay is increased twofold over the originally reported colorimetric method, and the lower limit of detection for the assay of a 1.0-ml plasma sample has been decreased t...

We describe a simple, rapid fluorometric assay for separate quantitative analysis of procainamide and N-acetylprocainamide in mixtures. The effective lenear range (fluorescence vs. concentration) in serum is 0.1 to 10.0 mg/liter, regardless of the ratio (by weight) of the two drugs from 1:10 to 10:1. Analytical recoveries by the extraction method used were 100.0 +/- 3.0% and 98.0 +/- 4.0%, resp...

Previous workers have shown that under certain clinical and experimental conditions, quinidine potentiates the neuromuscular blocking action of suxamethonium. This effect of quinidine has been demonstrated experimentally in a nerve-musde preparation in vivo while another antifibrillatory drug, procainamide, has also been shown to potentiate suxamethonium. Possible explanations of these drug int...

delayed repolarization syndromes. Mod Concepts Cardiovasc Dis 45: 117, 1976 28. Castellanos A, Salhanick L: Electrocardiographic patterns of procainamide cardiotoxicity. Am J Med Sci 253: 52, 1967 29. Epstein MA: Ventricular standstill during the intravenous procainamide treatment of ventricular tachycardia. Am Heart J 45: 890, 1953 30. Seiklos P, Chalme TM, Evans DW: Ventricular tachycardia af...