What effect does nitroglycerin have when taken with PDE-5 inhibitors?

Nitroglycerin is a nitrate that is commonly used for the management of angina pectoris, as it induces vasodilation and improves blood flow to the heart. When nitroglycerin is taken in conjunction with phosphodiesterase type 5 (PDE-5) inhibitors, such as sildenafil, tadalafil, or vardenafil, it can lead to a dangerous drop in blood pressure. This is because both medications promote vasodilation through different mechanisms, which can synergistically enhance the effects of each other in terms of lowering vascular resistance and causing hypotension.

When the blood vessels dilate too much, the body's ability to maintain blood pressure is compromised, potentially resulting in life-threatening scenarios such as severe hypotension. This risk is heightened in individuals who may already have underlying cardiovascular issues or are on other medications that can lower blood pressure. Thus, the interaction between nitroglycerin and PDE-5 inhibitors is clinically significant, as it underscores the importance of avoiding the combined use of these drugs to prevent serious adverse effects.