Morphine suppression of digitalis-induced ventricular arrhythmias.
The purpose of the study was to investigate the effect of morphine on digitalis-induced arrhythmias. Seventeen normokalemic dogs [serum potassium 3.9 +/- 0.3 mEg/L (+/- 1 S.D.)] and 19 hypokalemic dogs (serum potassium 2.2 +/- 0.3 mEg/L) were allocated to a morphine pretreatment group (morphine sulfate 3 mg/kg) or to a control group without morphine. Ouabain was administered by a constant infusion of 150 micrograms/kg/hr following an initial bolus of 20 micrograms/kg until animals developed ventricular tachycardia. In hypokalemic dogs, morphine pretreatment significantly (p less than 0.05) increased the digitalis dose required to initiate ventricular tachyarrhythmias (66 +/- 14 vs 37 +/- 11 micrograms ouabain/kg). In normokalemic dogs morphine did not affect the relationship between digitalis dose and arrhythmias. Thus, morphine pretreatment reduces the tendency for hypokalemia to potentiate digitalis-induced ventricular arrhythmias.
Department of Medicine (Cardiology), University of British Columbia, Vancouver, Canada.
S W
SW
Rabkin
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S
Einzig
D G
DG
Benditt
D000818:Animals; D001145:Arrhythmias, Cardiac / Q000139:chemically induced / Q000517:prevention & control*; D001794:Blood Pressure / Q000187:drug effects; D004071:Digitalis Glycosides / Q000037:antagonists & inhibitors*; D004285:Dogs; D005260:Female; D007008:Hypokalemia / Q000503:physiopathology; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D010042:Ouabain / Q000037:antagonists & inhibitors; D013610:Tachycardia / Q000139:chemically induced / Q000517:prevention & control
D004071:Digitalis Glycosides; D010042:Ouabain; D009020:Morphine