Isosorbide Dinitraat Retard Aurobindo (Isosorbide Dinitrate)

Isosorbide dinitrate belongs to the nitrate vasodilator class and is used in cardiovascular conditions where reduction of myocardial oxygen demand is required.

• Angina pectoris: decreases the frequency and severity of chest pain episodes.
• Chronic heart failure: improves exercise tolerance and reduces symptoms of dyspnea.
• Stable angina prophylaxis: provides long‑acting relief to prevent angina attacks during daily activities.

• Isosorbide dinitrate 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 vessels, producing vasodilation, reduced preload and afterload, and consequently lower myocardial oxygen consumption.

Isosorbide dinitrate may cause a range of adverse reactions, from mild to severe.

Common Side Effects

• Headache: throbbing pain often occurring shortly after dosing.
• Dizziness or light‑headedness: related to blood pressure lowering.
• Flushing: warm sensation and reddening of the skin.
• Hypotension: measurable drop in blood pressure, especially on standing.
• Nausea or vomiting: gastrointestinal discomfort.
• Tachycardia: compensatory increase in heart rate.

Serious or Rare Side Effects

• Severe hypotension: can lead to syncope or shock.
• Syncope: sudden loss of consciousness.
• Myocardial infarction: rare but reported in susceptible patients.
• Allergic reaction: rash, itching, or swelling.
• Severe bradycardia: markedly slow heart rate requiring medical attention.
• Methemoglobinemia: rare disorder affecting oxygen transport.

Before initiating therapy, clinicians should evaluate cardiovascular status and consider potential drug interactions.

• Blood pressure monitoring: check baseline and periodic readings to avoid excessive hypotension.
• Concomitant nitrate use: avoid combining with other nitrate preparations to prevent additive effects.
• Phosphodiesterase‑5 inhibitors: contraindicated due to risk of profound hypotension.
• Hepatic or renal impairment: dose adjustment may be required and close monitoring advised.
• Store at below 25°C: keep in the original container, protect from moisture and direct sunlight.

Isosorbide dinitrate interacts with several drug classes, requiring careful management.

Major Interactions (Avoid)

• Sildenafil, tadalafil, vardenafil: concurrent use can cause life‑threatening hypotension.
• Other nitrates (e.g., nitroglycerin): additive vasodilatory effect may lead to severe blood pressure drop.
• Antihypertensive agents (e.g., ACE inhibitors, ARBs): may amplify hypotensive response.
• Alcohol: potentiates vasodilatory effect and dizziness.
• Certain antifungal agents (e.g., ketoconazole): can increase plasma levels of the nitrate.

Moderate Interactions (Monitor Closely)

• Beta‑blockers: may mask tachycardia but require blood pressure monitoring.
• Calcium channel blockers: additive effect on vascular tone.
• Diuretics: may enhance volume depletion and hypotension.
• Antacids: can affect absorption if taken simultaneously.
• Azole antifungals: may modestly raise nitrate concentrations.