Hemodynamic interactions of verapamil and isoflurane.
The hemodynamic interactions of verapamil and isoflurane were studied in eight dogs. Left ventricular function was analyzed using a right heart bypass preparation to permit rigid hemodynamic control. Hemodynamic studies were performed at 0.7, 1.05, and 1.40% isoflurane before and during the maintenance of two stable levels of verapamil, administered intravenously by combining a bolus dose (0.2 mg X kg-1) with an infusion (3.0 and 6.0 micrograms X kg-1 X min-1). Isoflurane produced a concentration-dependent depression of left ventricular function as indicated by dP/dt max, per cent systolic shortening, and left ventricular function curves. This depression was enhanced in a dose-plasma concentration-dependent manner by verapamil and was reversed by calcium chloride. Isoflurane alone and the combination of verapamil and isoflurane decreased systemic vascular resistance in a dose-dependent fashion that was antagonized partially by calcium chloride. Therefore, verapamil can enhance the hemodynamic effects of isoflurane in a dose-related manner that needs to be considered when both drugs are administered together.
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002122:Calcium Chloride / Q000494:pharmacology; D002302:Cardiac Output / Q000187:drug effects; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D005112:Extracorporeal Circulation; D006439:Hemodynamics / Q000187:drug effects*; D007530:Isoflurane / Q000494:pharmacology*; D008738:Methyl Ethers / Q000494:pharmacology*; D009200:Myocardial Contraction / Q000187:drug effects; D014655:Vascular Resistance / Q000187:drug effects; D014700:Verapamil / Q000494:pharmacology*
D008738:Methyl Ethers; D014700:Verapamil; D007530:Isoflurane; D002122:Calcium Chloride