The Effect of Low Dose Sildenafil On Verapamil - Induced Cardiovascular Toxicity in Rats.

Background: Experimental studies have shown that sildenafil may have significant cardio protective effects if used in low doses. The aim of this study was to compare the efficacies of glucagon and sildenafil treatments in anesthetized rats receiving verapamil overdose. Methods: Male Sprague-Dawley rats (n = 8 per group), weighing 300-350 g were used in the study. The iliac arteries and veins of rats bilaterally were catheterized under urethane anaesthesia. Toxicity was induced by infusion of verapamil 15 mg/kg until 10 minutes. The rats received continuous infusion of sildenafil (0.06 mg/kg/h), glucagon (2mg/kg/h) or 0.3mcg/kg/min noradrenaline added to sildenafil 0.06 mg/kg/h infusion. Results: The AUC10-60 min of MAP plot was significantly lower in the control group, and both treatments produced significant increases in the AUC10-60 min of MAP plots (p < 0.05). Noradrenaline added to the sildenafil infusion was found to generate better values in the cardiovascular parameters (p < 0.01). Heart rate values were restored better in the group that received noradrenaline adjunct. Conclusion: The results of this study may imply that sildenafil alone is no better than glucagon, the classical treatment approach in verapamil toxicity. However, sildenafil may be more effective if used with a vasopressor adjunct.