Effect of doxorubicin and verapamil on circulatory system in rabbits

The cardiovascular effect of a single intravenous dose of doxorubicin (DXR) given to the rabbits pretreated intravenously for 3 weeks with DXR, verapamil (Vp) or both drugs was investigated. It was found that cardiac index and stroke index were higher in the rabbits pretreated with DXR plus Vp than with DXR alone. Mean arterial blood pressure was lower in each group of animals. However, total peripheral resistance was reduced significantly in both groups of rabbits pretreated with Vp. DXR produced a significant decrease of the heart rate and dangerous arrhythmias in rabbits pretreated with both drugs. Histologically degenerative changes in nuclei but less in myofibrils were observed in this group of animals.