Get emergency medical help if you have signs of an allergic reaction to Nitrostat: hives, sweating, pale skin; nausea, vomiting; feeling weak or light-headed; difficult breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have:
severe or throbbing headaches that do not become less severe with continued use of Nitrostat;
pounding heartbeats or fluttering in your chest;
slow heart rate;
a light-headed feeling, like you might pass out;
blurred vision or dry mouth; or
heart attack symptoms - chest pain or pressure, pain spreading to your jaw or shoulder, nausea, sweating.
Nitroglycerin can cause severe headaches that should become less severe as you continue to use the medicine.
Common Nitrostat side effects may include:
flushing (sudden warmth, redness, or tingly feeling);
feeling light-headed, fainting;
headache, dizziness; or
numbness, tingling, burning pain.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
 Nitrostat side effects (more detail)
