International journal of obstetric anesthesia
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Int J Obstet Anesth · Oct 1998
Cardiovascular consequences of the concomitant administration of nifedipine and magnesium sulfate in pigs.
There is concern regarding the interaction of magnesium sulfate and nifedipine used concomitantly in obstetrical patients, because both are calcium channel antagonists and may induce myocardial depression as well as peripheral vasodilatation. The objective of this study was to determine the hemodynamic consequences of concomitant administration of nifedipine and magnesium sulfate in anesthetized pigs. Twelve pigs were anesthetized with sodium pentobarbital, intubated mechanically ventilated. ⋯ Treatment with calcium chloride or ephedrine was only partially successful in improving myocardial contractility. Phenylephrine increased peripheral vascular resistance and MAP, but did not improve myocardial function. In conclusion, the depressive effects of nifedipine and magnesium sulfate on the cardiovascular system are potentiated when administered concomitantly.