What is a typical starting IV infusion rate for nitroglycerin in ACS?

• A. 5–10 mcg/min
• B. 0.5–1 mcg/min
• C. 50–100 mcg/min
• D. 100–200 mcg/min

Answer: (A)

Starting intravenous nitroglycerin in ACS focuses on delivering a small, titratable dose to relieve ischemia while keeping blood pressure stable. The typical starting infusion is 5–10 micrograms per minute. From there, you increase the rate in small steps (usually 5–10 mcg/min) every few minutes until the patient’s chest pain improves or the blood pressure is at an acceptable level. This approach avoids the risk of marked hypotension that would come with higher initial doses such as tens or hundreds of micrograms per minute, and it prevents subtherapeutic dosing that wouldn’t relieve ischemia.

The choice reflects nitroglycerin’s mechanism: venodilation lowers preload and myocardial oxygen demand, which helps alleviate angina and can improve myocardial perfusion. Always monitor blood pressure and heart rate during infusion, and avoid use if the patient is hypotensive, has a suspected right ventricular infarct, or has recently taken phosphodiesterase inhibitors.