Isomel Sr (Isosorbide Mononitrate)

Isosorbide Mononitrate is a nitrate used in the management of coronary artery disease and related anginal conditions.

• Chronic stable angina: reduces the frequency and severity of angina attacks.
• Angina pectoris: improves exercise tolerance and delays onset of chest pain.
• Prophylaxis of angina episodes: provides long‑term prevention of symptomatic ischemia.

• Isosorbide Mononitrate is metabolized to nitric oxide, which activates guanylate cyclase in vascular smooth muscle cells. The resulting increase in cyclic GMP leads to relaxation of arterial and venous smooth muscle, decreasing preload and afterload, and thereby improving myocardial oxygen supply‑demand balance.

Isomel Sr may cause a range of adverse reactions, most of which are dose‑related and reversible.

Common Side Effects

• Headache: mild to moderate throbbing pain.
• Dizziness or light‑headedness.
• Flushing: warmth and redness of the skin.
• Hypotension: low blood pressure, especially on standing.
• Nausea or gastrointestinal discomfort.
• Palpitations: awareness of heartbeat.

Serious or Rare Side Effects

• Severe hypotension leading to syncope.
• Acute myocardial infarction in susceptible patients.
• Life‑threatening allergic reactions (anaphylaxis).
• Tachycardia or arrhythmias.
• Methemoglobinemia (rare blood disorder).

Before initiating therapy with Isomel Sr, several safety considerations should be observed.

• Blood pressure monitoring: check baseline and periodic readings.
• Concomitant nitrate use: avoid combining with other nitrate preparations.
• Phosphodiesterase‑5 inhibitors: do not use together due to risk of profound hypotension.
• Hepatic or renal impairment: adjust dose and monitor organ function.
• Abrupt discontinuation: taper gradually to prevent rebound angina.
• Store at room temperature: keep in the original container, protect from moisture and direct sunlight.

Isomel Sr can interact with several drug classes; awareness helps prevent adverse events.

Major Interactions (Avoid)

• Other nitrates (e.g., nitroglycerin): additive vasodilatory effect.
• Phosphodiesterase‑5 inhibitors (e.g., sildenafil): risk of severe hypotension.
• Potent antihypertensives (e.g., clonidine): may cause excessive blood pressure drop.

Moderate Interactions (Monitor Closely)

• Diuretics: may enhance hypotensive response.
• ACE inhibitors or ARBs: monitor blood pressure for additive effects.
• Beta‑blockers: assess for bradycardia or excessive blood pressure reduction.
• Calcium channel blockers: watch for combined vasodilatory impact.
• Antiplatelet agents: monitor for bleeding tendency.