Monoket Od (Isosorbide Mononitrate)

Isosorbide Mononitrate is indicated for conditions within the chronic stable angina spectrum, where nitrate‑mediated vasodilation improves myocardial oxygen supply.

• Chronic stable angina pectoris: reduces the frequency of angina attacks and enhances exercise tolerance.
• Angina prophylaxis: helps prevent episodes of chest pain during physical activity.
• Ischemic heart disease: improves myocardial oxygen balance by lowering cardiac workload.

• Isosorbide Mononitrate is metabolized to release nitric oxide, which activates guanylate cyclase in vascular smooth muscle. The resulting increase in cyclic GMP leads to relaxation of arterial and venous smooth muscle, producing vasodilation. This reduces both preload and afterload, decreasing myocardial oxygen demand while improving coronary blood flow, thereby alleviating angina symptoms.

Common Side Effects

• Headache: a frequent transient sensation due to vasodilation.
• Dizziness or light‑headedness: often related to blood pressure lowering.
• Flushing: warm sensation of the skin, especially on the face.
• Nausea: mild gastrointestinal upset.
• Palpitations: awareness of heartbeats.
• Hypotension: mild drop in blood pressure.

Serious or Rare Side Effects

• Severe hypotension: marked blood pressure reduction requiring medical attention.
• Syncope: sudden loss of consciousness.
• Myocardial infarction: rare but possible cardiac event.
• Life‑threatening arrhythmias: irregular heart rhythms.
• Anaphylactic reaction: rare severe allergic response.
• Methemoglobinemia: abnormal hemoglobin affecting oxygen delivery.

When prescribing Isosorbide Mononitrate, clinicians should consider several safety measures.

• Dose titration: start with a low dose and adjust gradually based on tolerance.
• Concomitant PDE‑5 inhibitors: avoid use together due to risk of profound hypotension.
• Renal impairment: assess kidney function and modify dose if necessary.
• Hepatic impairment: use with caution and monitor liver status.
• Pregnancy and lactation: safety not established; avoid unless clearly needed.
• Store at ambient temperature below 25°C: keep in the original container, protect from moisture.

Isosorbide Mononitrate may interact with several drug classes, requiring careful management.

Major Interactions (Avoid)

• Sildenafil and other PDE‑5 inhibitors: can cause severe hypotension.
• Other nitrate medications: additive vasodilatory effect may lead to dangerous blood pressure drops.
• Antihypertensive agents: may produce excessive lowering of blood pressure.

Moderate Interactions (Monitor Closely)

• Diuretics: may enhance hypotensive response.
• Antiplatelet agents (e.g., aspirin, clopidogrel): increase risk of bleeding.
• Alcohol: can amplify dizziness and hypotension.
• Certain antifungal agents (e.g., ketoconazole): may affect nitrate metabolism.