Final answer:
Milrinone is a phosphodiesterase III inhibitor used to treat heart failure, which increases cyclic AMP and causes vasodilation, leading to a decrease in peripheral vascular resistance. It cannot be taken orally and is typically given through IV infusion.
Step-by-step explanation:
Milrinone is a medication that has several important effects on the cardiovascular system. Notably, it functions as a phosphodiesterase III inhibitor, which leads to an increase in cyclic AMP. This increase results in potent vasodilation, meaning it helps to widen blood vessels. Consequently, Milrinone effectively decreases peripheral vascular resistance, thereby reducing the workload on the heart and improving cardiac output. Given these properties, Milrinone is commonly used in the management of heart failure. However, due to its pharmacokinetic profile, it cannot be effectively given orally and is usually administered via intravenous infusion in a hospital setting.