Isosorbide Mononitrato Eg (Isosorbide 5 Mononitrate)

Isosorbide-5-mononitrate is an antianginal agent that reduces myocardial oxygen demand.

• Prevention of angina pectoris: decreases the frequency of angina attacks in patients with stable coronary disease.
• Chronic stable angina: improves exercise tolerance and reduces chest‑pain episodes.
• Stable coronary artery disease: helps control symptoms associated with myocardial ischemia.

• Isosorbide-5-mononitrate is metabolized to release nitric oxide, which activates guanylate cyclase in vascular smooth muscle. The resulting increase in cyclic GMP causes relaxation of arterial and venous smooth muscle, producing vasodilation, reducing preload and afterload, and thereby lowering myocardial oxygen consumption.

Isosorbide-5-mononitrate may cause a range of adverse reactions, most of which are related to its vasodilatory action.

Common Side Effects

• Headache: throbbing pain often occurring shortly after dosing.
• Flushing: warm sensation and redness of the skin.
• Dizziness or light‑headedness: especially when standing quickly.
• Nausea: mild to moderate upset stomach.
• Hypotension: measurable drop in blood pressure.

Serious or Rare Side Effects

• Severe hypotension: marked blood‑pressure fall requiring medical attention.
• Syncope: sudden loss of consciousness.
• Allergic reactions: rash, pruritus, or rare severe cutaneous adverse reactions such as Stevens‑Johnson syndrome.

When prescribing or dispensing isosorbide-5-mononitrate, clinicians should consider several safety measures.

• Avoid abrupt discontinuation: may precipitate rebound angina.
• Use cautiously in patients with low blood pressure: monitor hemodynamics.
• Concurrent use with other nitrates: risk of additive hypotension.
• Renal or hepatic impairment: consider dose adjustment.
• Pregnancy Category B: use only if benefit outweighs potential risk.
• Store at room temperature: keep in original container, protect from moisture and light.

Isosorbide-5-mononitrate can interact with several drug classes, requiring attention to avoid harmful effects.

Major Interactions (Avoid)

• Phosphodiesterase‑5 inhibitors (e.g., sildenafil): can cause profound hypotension.
• Other organic nitrates or nitroglycerin: additive vasodilatory effect leading to severe hypotension.

Moderate Interactions (Monitor Closely)

• Antihypertensive agents (ACE inhibitors, beta‑blockers): may enhance blood‑pressure lowering.
• Diuretics: may increase risk of orthostatic hypotension.
• Alcohol: can potentiate vasodilatory effects and dizziness.