Class Explorer · Cardiovascular
Nitrates
Nitric oxide donors that relax vascular smooth muscle. Venodilation at low doses drops preload, which is where most of the anginal relief comes from; arterial dilation follows at higher doses.
Members
Also in this class: Isosorbide dinitrate · Isosorbide mononitrate. Full pages arrive as the library grows.
Compare the members
Nitroglycerin (glyceryl trinitrate)
- Onset
- 1 to 3 min sublingual
- Duration
- 20 to 30 min
- Role
- Rescue; infusion for acute pulmonary oedema
Shared across the class
- Indications
- Angina, acute relief and prophylaxis · Acute heart failure with hypertension · Hypertensive emergency (infusion)
- Adverse effects
- Headache · Hypotension · Reflex tachycardia · Flushing
- Contraindications
- Concurrent PDE5 inhibitor · Severe aortic stenosis · Hypotension · Right ventricular infarction
- Monitoring
- Blood pressure, particularly the first dose · Headache, which usually settles and is not a reason to abandon the drug · How many sublingual doses are being used per week: a rising count is unstable angina until proven otherwise
What makes each agent different
- Sublingual glyceryl trinitrate works in minutes and is gone in minutes: it is a rescue drug. Oral mononitrate lasts hours: it is a prophylactic.
- Tolerance develops with continuous exposure, so long-acting regimens are built around a deliberate nitrate-free interval, usually overnight. A patch worn 24 hours a day stops working.
The nitrate plus sildenafil interaction is not a caution, it is a contraindication, and the question has to be asked out loud rather than assumed.
In inferior myocardial infarction with right ventricular involvement, the preload the nitrate removes is the preload keeping the patient alive.
Last reviewed 2026-08-16 · Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed.