The most common cause of renal artery stenosis is atherosclerosis, the same condition that causes narrowing of the arteries in coronary heart disease and stroke, and the risk factors are the same as well. Cholesterol plaques build up along the walls of the renal artery and gradually cause narrowing.
Oxytocin is a commonly used uterotonic that can cause significant and even fatal hypotension, particularly when given as a bolus. The resulting hypotension can be produced by a decrease in systemic vascular resistance or cardiac output through a decrease in venous return.
The exact mechanism of the hypotensive action of prazosin is unknown. Prazosin causes a. decrease in total peripheral resistance and was originally thought to have a direct relaxant. action on vascular smooth muscle. Recent animal studies, however, have suggested that the. vasodilator effect of prazosin is also related to blockade of postsynaptic alpha-adrenoceptors.