SC-36602, a new antiarrhythmic agent: comparison of its cardiovascular profile with that of other antiarrhythmic drugs.
The cardiovascular profile of SC-36602, a new class 1A/1B antiarrhythmic agent, was compared to those of disopyramide, lidocaine, mexiletine, flecainide, encainide, lorcainide, and quinidine. These drugs were compared at their respective canine antiarrhythmic doses in a hemodynamic evaluation using anesthetized dogs. In another test using anesthetized dogs, the cardiovascular effects of cumulative doses of SC-36602 were assessed. The direct negative inotropic potential of each drug was also determined using isolated cat papillary muscles. In the hemodynamic study, SC-36602 and quinidine did not cause significant myocardial depression, measured as a decrease in the maximal first derivative of the left ventricular pressure. (Heart rate and diastolic filling pressure were not controlled in order to mimic clinical conditions). SC-36602, mexiletine, flecainide, and quinidine increased heart rate. SC-36602 and mexiletine caused a small increase in mean arterial pressure, whereas disopyramide and quinidine decreased it. Disopyramide was the only drug studied that increased left ventricular end-diastolic pressure. SC-36602, quinidine, and mexiletine increased index of cardiac effort. Disopyramide caused a decrease in the latter. Disopyramide, flecainide, encainide, and lorcainide lengthened the ECG intervals. Cumulative intravenous doses of SC-36602 up to 50 mg/kg produced significant decreases in mean arterial pressure, increases in heart rate, and increases in P-R and QRS intervals of the ECG relative to placebo-matched controls. SC-36602 had the least direct negative inotropic action of the drugs studied, as measured in isolated papillary muscles. These data suggest SC-36602, when compared to the other antiarrhythmic drugs studied, has the least amount of hemodynamic side-effects at its antiarrhythmic dose.
Frederick
L G
LG
Department of Biological Research, G.D. Searle & Company, Skokie, Illinois 60077.
Hatley
F R
FR
McDonald
S J
SJ
Stamm
M H
MH
Garthwaite
S M
SM
D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D002415:Cats; D004285:Dogs; D005260:Female; D006439:Hemodynamics / Q000187:drug effects*; D066298:In Vitro Techniques; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D010210:Papillary Muscles / Q000187:drug effects; D011744:Pyrimidinones / Q000494:pharmacology*
D000889:Anti-Arrhythmia Agents; D011744:Pyrimidinones; C051827:SC 36602