What are the typical routes and starting doses of nitroglycerin for ACS?

• A. Sublingual 0.4 mg every 5 minutes for up to 3 doses
• B. IV infusion 5–10 mcg/min
• C. Both of the above
• D. Topical ointment 0.5 inch every 6 hours

Answer: (C)

In ACS, nitroglycerin is used by several routes to rapidly relieve chest pain and reduce myocardial oxygen demand, with each route offering a different onset and duration. Sublingual nitroglycerin provides quick relief and is started at 0.4 mg every 5 minutes for up to three doses; if pain persists, you move to an IV infusion for continuous, titratable control, beginning at 5–10 mcg/min and adjusting every few minutes based on pain relief and blood pressure. Topical nitroglycerin paste is another option for ongoing venodilation, with a typical starting application of 0.5 inch applied to the chest wall and redosed every 6 hours, recognizing its slower onset compared with sublingual dosing. Together, these routes cover immediate relief, continuous control, and longer-acting effects, so acknowledging all three routes with their starting doses explains why both routes and the topical option are considered appropriate in ACS. Remember to monitor blood pressure and avoid nitroglycerin if hypotension or suspected right ventricular infarction is present, and be cautious with PDE-5 inhibitors.