Nitronal (Glyceryl Trinitrate)

Nitronal (glyceryl trinitrate) is used in the anti‑anginal drug class to manage coronary artery disease‑related chest pain.

• Acute angina pectoris: rapid relief of chest pain by dilating coronary vessels.
• Prophylaxis of angina attacks: reduces frequency of episodes when taken before exertion.
• Chronic stable angina: improves exercise tolerance by decreasing myocardial oxygen consumption.

• Glyceryl trinitrate is enzymatically converted to nitric oxide within vascular smooth‑muscle cells. The released nitric oxide activates soluble guanylate cyclase, increasing cyclic GMP levels, which leads to relaxation of smooth muscle and vasodilation of both veins and arteries. This reduces preload and afterload, lowers myocardial oxygen demand, and improves coronary blood flow, alleviating ischemic chest pain.

Glyceryl trinitrate may cause a range of adverse reactions, varying from mild to serious.

Common Side Effects

• Headache: throbbing pain often triggered by vasodilation.
• Flushing: warmth and redness of the skin, especially on the face.
• Dizziness or light‑headedness: related to blood pressure changes.
• Hypotension: mild drop in blood pressure causing faintness.
• Nausea: occasional upset stomach.
• Tachycardia: compensatory increase in heart rate.

Serious or Rare Side Effects

• Severe hypotension: marked blood pressure fall that may require medical intervention.
• Syncope: sudden loss of consciousness due to inadequate cerebral perfusion.
• Myocardial infarction: rare but possible in patients with unstable coronary disease.
• Allergic reactions (anaphylaxis): swelling, rash, or breathing difficulty.
• Methemoglobinemia: abnormal hemoglobin that impairs oxygen delivery.
• Intense headache with visual disturbances: may indicate intracranial pressure changes.

Before using Nitronal, consider the following safety measures.

• Dose titration: start with the lowest effective dose and adjust under medical supervision.
• Avoid use with phosphodiesterase‑5 inhibitors: concurrent use may cause profound hypotension.
• Monitor blood pressure: check for excessive drops, especially in the standing position.
• Use with caution in patients with anemia or increased intracranial pressure.
• Store at below 25°C: keep in the original container, protect from moisture and light.

Nitronal can interact with several medicines; awareness helps prevent adverse events.

Major Interactions (Avoid)

• Sildenafil, tadalafil, vardenafil: concurrent use can cause severe hypotension.
• Other organic nitrates (e.g., isosorbide dinitrate): additive vasodilatory effect leading to dangerous blood pressure fall.
• Alcohol: potentiates hypotensive effect.

Moderate Interactions (Monitor Closely)

• Antihypertensives (beta‑blockers, ACE inhibitors): may enhance blood pressure lowering.
• Diuretics: may increase risk of orthostatic hypotension.
• CYP3A4 inhibitors (e.g., erythromycin): may increase plasma levels of nitrates.