Related Experiment Videos
7-oxo PGI2 dramatically increases the safety margin of digitalis
Z Szilvássy1, L Szekeres, E Udvary
1Department of Pharmacology, Szent-Györgyi Albert University Medical School, Szeged, Hungary.
Bratislavske Lekarske Listy
|March 1, 1991
Summary
Pretreatment with 7-oxo PGI2 significantly increased the dose of ouabain required to induce cardiac rhythm disturbances in dogs. This finding suggests 7-oxo PGI2 enhances the safety margin of cardiac glycosides.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Previous studies demonstrated 7-oxo PGI2's efficacy against ouabain-induced rhythm disturbances in guinea pigs.
- Maximal protection was observed 48 hours post-administration of 50 micrograms/kg 7-oxo PGI2 intramuscularly.
Purpose of the Study:
- To investigate the influence of 7-oxo PGI2 pretreatment on cardiac glycoside-induced positive inotropic responses.
- To determine the effect of 7-oxo PGI2 on the development of rhythm disturbances at higher ouabain doses in dogs.
Main Methods:
- Experiments were conducted on anesthetized, artificially ventilated mongrel dogs (9-11 kg).
- Continuous recordings included ECG, left ventricular pressure, and maximal positive/negative dP/dt.
- Ouabain was administered via intermittent intravenous infusion until cardiac arrest.
Main Results:
- 7-oxo PGI2 pretreatment increased the ouabain dose required for ventricular extrasystoles (62 vs. 53.3 µg/kg), ventricular tachycardia (97 vs. 80 µg/kg), and cardiac arrest (100 vs. 87 µg/kg).
- The dose of ouabain to achieve 25% of the maximal positive inotropic effect was significantly lower in the pretreated group (14.2 vs. 31.7 µg/kg).
Conclusions:
- 7-oxo PGI2 pretreatment significantly increases the dose of ouabain needed to induce arrhythmias.
- 7-oxo PGI2 enhances the safety margin of ouabain, reducing the risk of cardiac glycoside toxicity.