Nitroglycerine, or nitroglycerin in the United States, is potent vasodilator, or an agent that decreases blood pressure, which functions by relaxing vascular muscles. Therapeutic dosages reduce the blood pressure and slightly increase heart rate. It is used to prevent, treat and manage angina. When placed under the tongue, onset is a mere two minutes.

It is contraindicated in those who have severe anaemia, head trauma and hypotension. Common side effects are headaches, which occur in 50% of patients, and hypotension. Life-threatening side effects include circulatory collapse and anaphylaxis.

There are a variety of routes of administration:

• sublingual, or a tablet put under the tongue
• extended-release buccal, or a tablet placed between the lip and gum
• extended-release tablet taken by mouth
• translingual spray, or application by spraying on or under the tongue
• transdermal ointment, or ointment placed on the skin as treatment for Raynaud's disease
• intravenous (IV)