Nitroglycerin for angina — what you need to know

If you get sudden chest pain from angina, nitroglycerin can stop it fast. It relaxes blood vessels, which eases the heart's workload and can reduce pain within minutes. This guide explains the forms of nitroglycerin, how to use each one, common side effects, and the safety steps to avoid dangerous drops in blood pressure.

Forms and how quickly they work

Sublingual tablets (under the tongue) and spray are made for sudden chest pain. They usually start working in 1–5 minutes and last about 30 minutes. Patches and ointment are for preventing angina, not for immediate relief; they release medicine slowly over hours. Intravenous nitroglycerin is used in hospital settings for severe chest pain or heart attacks.

Brands you might see include Nitrostat (tablets) and Nitro-Dur (patches). Keep the tablets in their original glass container — light and air reduce effectiveness.

How to use nitroglycerin for chest pain

1. Sit or lie down at the first sign of chest pain. Standing can make dizziness worse.

2. Place one sublingual tablet under your tongue or spray one dose onto/under the tongue. Don’t swallow right away—let it dissolve.

3. Wait 5 minutes. If pain continues, you can take a second dose. After another 5 minutes, a third dose is allowed. If pain isn’t gone after three doses (15 minutes), call emergency services right away.

For spray, follow the pump directions on the bottle. For patches, apply to clean, dry skin once daily; many doctors recommend removing the patch for 10–12 hours each day to prevent tolerance (loss of effect).

Store tablets at room temperature in their original bottle. Keep spray capped and away from heat. Check expiry dates; old nitroglycerin can be ineffective when you need it most.

Warnings, side effects, and interactions

Common side effects: headache, flushing, lightheadedness, and low blood pressure. If you feel faint, lie down with your legs raised until you feel better.

Do not take nitroglycerin with erectile dysfunction drugs like sildenafil or vardenafil (within 24 hours) or tadalafil (within 48 hours). Combining them can cause a dangerous drop in blood pressure. Also avoid alcohol and other blood-pressure-lowering medicines unless your doctor approves.

Tell your doctor if you have very low blood pressure, severe anemia, or a recent head injury; nitroglycerin may not be safe. If you’re pregnant or breastfeeding, discuss risks and benefits with your provider.

Always talk with your doctor about the right dose and which form suits your lifestyle. Keep emergency numbers handy, carry your nitroglycerin if you’ve been prescribed it, and replace it before it expires. If chest pain lasts more than 15 minutes or comes with sweating, shortness of breath, or fainting, get emergency help immediately.