Isosorbide Mononitrate Milpharm (Isosorbide Mononitrate, Diluted Ph. Eur.)

Isosorbide Mononitrate belongs to the organic nitrate class and is employed in the management of coronary artery disease‑related angina.

• Chronic stable angina: reduces the frequency and severity of angina attacks.
• Angina pectoris: improves exercise tolerance and decreases chest pain episodes.
• Ischemic heart disease: enhances 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 causes relaxation of arterial and venous vessels, producing vasodilation that lowers preload and afterload, thereby improving myocardial oxygen supply‑demand balance.

Isosorbide Mononitrate may cause a range of adverse reactions, most of which are mild and transient.

Common Side Effects

• Headache: throbbing pain often occurring early in therapy.
• Dizziness or light‑headedness: related to blood pressure reduction.
• Flushing: warm sensation and reddening of skin.
• Nausea or upset stomach.
• Palpitations: awareness of heartbeat.
• Hypotension: mild drop in blood pressure.

Serious or Rare Side Effects

• Severe hypotension: marked blood pressure fall requiring medical attention.
• Syncope: sudden loss of consciousness.
• Myocardial infarction: rare but reported in vulnerable patients.
• Life‑threatening arrhythmias.
• Anaphylactic or severe allergic reactions.
• Stevens‑Johnson syndrome or toxic epidermal necrolysis.

Before initiating therapy, clinicians should evaluate patient‑specific factors and monitor for potential complications.

• Cardiovascular assessment: confirm stable hemodynamics before use.
• Avoid abrupt discontinuation: taper to prevent rebound angina.
• Blood pressure monitoring: check regularly, especially after dose changes.
• Hepatic impairment: use with caution as metabolism may be altered.
• Concomitant PDE‑5 inhibitors: avoid due to risk of profound hypotension.
• Store at room temperature: keep in the original pack, protect from moisture and direct sunlight.

Isosorbide Mononitrate can interact with several drug classes; awareness helps prevent adverse events.

Major Interactions (Avoid)

• Sildenafil, tadalafil, and other PDE‑5 inhibitors: may cause severe hypotension.
• Other organic nitrates (e.g., nitroglycerin): additive vasodilatory effect leading to dangerous blood pressure drops.
• Potent antihypertensives (e.g., ACE inhibitors, ARBs): risk of excessive blood pressure lowering.

Moderate Interactions (Monitor Closely)

• Azithromycin and other macrolide antibiotics: may increase nitrate plasma levels.
• Antidiabetic agents (e.g., insulin, sulfonylureas): enhanced risk of hypoglycemia.
• Diuretics: possible electrolyte disturbances and amplified hypotensive response.