Monoket (Isosorbide Mononitrate)

Monoket belongs to the organic nitrate class and is used to manage angina‑related conditions.

• Chronic stable angina pectoris: reduces the frequency and severity of angina episodes.
• Prevention of angina attacks: maintains adequate myocardial oxygen supply during daily activities.
• Exercise‑induced angina: improves exercise tolerance by decreasing 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, leading to vasodilation, reduced preload and afterload, and enhanced myocardial oxygen delivery.

Isosorbide mononitrate may cause a range of adverse reactions.

Common Side Effects

• Headache: mild to moderate throbbing pain, often transient.
• Dizziness or light‑headedness: related to blood pressure lowering.
• Flushing: warm sensation and reddening of skin, especially on the face.
• Nausea: occasional upset stomach or vomiting.
• Palpitations: awareness of heartbeat acceleration.

Serious or Rare Side Effects

• Severe hypotension: marked drop in blood pressure requiring medical attention.
• Syncope: sudden loss of consciousness due to inadequate cerebral perfusion.
• Myocardial infarction: rare but possible if coronary flow is compromised.
• Allergic reaction: rash, itching, swelling, or difficulty breathing.
• Stevens‑Johnson syndrome: rare severe skin reaction.

Before initiating therapy, clinicians should consider several safety measures.

• Blood pressure monitoring: check for hypotension, especially after the first dose.
• Concomitant nitrates: avoid using other nitrate preparations to prevent excessive vasodilation.
• PDE5 inhibitors: do not combine with sildenafil, tadalafil, or similar agents.
• Hepatic impairment: use with caution; dose adjustment may be required.
• Renal impairment: monitor renal function and adjust dose if necessary.
• Pre‑operative use: discontinue at least 24 hours before elective surgery.
• Store at room temperature: keep in the original container, protect from moisture and direct sunlight.

Isosorbide mononitrate can interact with several drug classes.

Major Interactions (Avoid)

• Other organic nitrates (e.g., nitroglycerin): risk of profound hypotension.
• Phosphodiesterase‑5 inhibitors (e.g., sildenafil, tadalafil): may cause severe blood pressure fall.
• Potent vasodilators (e.g., hydralazine): additive blood pressure effects.

Moderate Interactions (Monitor Closely)

• Antihypertensive agents (ACE inhibitors, beta‑blockers): may enhance hypotensive response.
• Diuretics: increased risk of volume depletion and low blood pressure.
• Alcohol: can potentiate vasodilatory effects and dizziness.
• Smoking: induces metabolism, potentially reducing efficacy.