Monopront (Isosorbide Mononitrate)

Monopront belongs to the organic nitrate class and is employed in the management of ischemic heart disease and heart failure.

• Chronic stable angina: reduces the frequency and severity of angina attacks by improving myocardial oxygen supply.
• Heart failure: alleviates symptoms such as dyspnea and fatigue by decreasing cardiac preload and afterload.
• Ischemic heart disease: helps prevent episodes of chest pain through sustained vasodilation.

• 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 vessels, lowering both preload and afterload, and thereby improving myocardial oxygen balance and reducing cardiac workload.

Isosorbide mononitrate may cause a range of adverse reactions, most of which are dose‑related and transient.

Common Side Effects

• Headache: often described as throbbing and may improve with continued therapy.
• Dizziness or light‑headedness, especially on standing.
• Flushing of the face or upper torso.
• Nausea or mild gastrointestinal upset.
• Palpitations or tachycardia.
• Hypotension: mild drop in blood pressure.

Serious or Rare Side Effects

• Severe hypotension leading to syncope.
• Acute myocardial infarction in susceptible patients.
• Life‑threatening allergic reactions (anaphylaxis, rash, swelling).
• Methemoglobinemia, a rare blood disorder.
• Persistent or worsening chest pain despite therapy.
• Unexplained fainting episodes.

Before initiating therapy, clinicians should consider several safety factors.

• Dose titration: start with a low dose and increase gradually to minimise hypotension.
• Renal impairment: adjust dosing or monitor renal function closely.
• Hepatic impairment: use with caution; monitor liver enzymes.
• Concomitant nitrate therapy: avoid due to additive vasodilatory effects.
• Pregnancy and lactation: safety not established; weigh risks and benefits.
• Store at room temperature: keep in the original container, protect from moisture and light.

Isosorbide mononitrate can interact with several drug classes, requiring careful management.

Major Interactions (Avoid)

• Other nitrates (e.g., nitroglycerin): may cause profound hypotension.
• Phosphodiesterase‑5 inhibitors (e.g., sildenafil, tadalafil): risk of severe blood pressure drop.
• Sodium nitrite: increased risk of methemoglobinemia.

Moderate Interactions (Monitor Closely)

• Antihypertensives (ACE inhibitors, beta‑blockers, calcium channel blockers): additive blood‑pressure‑lowering effect.
• Diuretics: may enhance orthostatic hypotension.
• Alcohol: can increase dizziness and vasodilatory responses.