Nitrospray (Glyceryl Trinitrate)

Glyceryl Trinitrate is used in the anti‑anginal and vasodilator pathway to relieve myocardial ischemia.

• Angina pectoris: rapid relief of chest pain by dilating coronary arteries.
• Acute coronary syndrome: improves coronary blood flow during ischemic episodes.
• Heart failure: reduces preload and afterload, aiding symptomatic management.

• Glyceryl Trinitrate acts as a nitric‑oxide donor. After sublingual absorption, it is converted to nitric oxide, which activates guanylate cyclase in vascular smooth muscle, increasing cyclic GMP levels. Elevated cGMP leads to relaxation of smooth muscle, causing vasodilation of veins and arteries, lowering cardiac preload and afterload and improving myocardial oxygen supply.

Adverse reactions may occur with Nitrospray use.

Common Side Effects

• Headache: throbbing pain often occurring shortly after administration.
• Flushing: warmth and redness of the face or neck.
• Dizziness: sensation of light‑headedness, especially when standing quickly.
• Hypotension: mild drop in blood pressure causing faintness.
• Tachycardia: compensatory increase in heart rate.
• Nausea: mild stomach upset.

Serious or Rare Side Effects

• Severe hypotension: marked blood pressure fall leading to syncope.
• Syncope: sudden loss of consciousness.
• Myocardial infarction: rare but possible in susceptible patients.
• Allergic reaction: rash, itching, or swelling of the face and throat.

Before using Nitrospray, consider the following precautions.

• Avoid use in severe hypotension: monitor blood pressure prior to administration.
• Contraindicated with recent phosphodiesterase‑5 inhibitor use: risk of profound hypotension.
• Caution in patients with anemia or increased intracranial pressure: monitor clinical status.
• Do not exceed prescribed number of sprays: excessive dosing can precipitate severe vasodilation.
• Keep away from children: accidental ingestion may cause life‑threatening hypotension.
• Store at below 25°C: keep in the original pack, protect from moisture and direct sunlight.

Nitrospray may interact with several drug classes.

Major Interactions (Avoid)

• Other nitrates (e.g., isosorbide dinitrate): additive vasodilatory effect leading to severe hypotension.
• Phosphodiesterase‑5 inhibitors (e.g., sildenafil): risk of profound blood pressure fall.
• Guanylate cyclase stimulators: may amplify nitric‑oxide mediated vasodilation.

Moderate Interactions (Monitor Closely)

• Antihypertensives (beta‑blockers, ACE inhibitors): may enhance blood pressure lowering.
• Diuretics: can contribute to volume depletion and hypotension.
• Alcohol: potentiates vasodilatory effects, increasing dizziness and hypotension.