Isomex (Isosorbide Mononitrate)

Isomex belongs to the organic nitrate class and is used to manage coronary‑related conditions.

• Prophylaxis of angina pectoris: reduces the frequency and severity of angina attacks.
• Chronic heart failure: improves exercise tolerance and reduces cardiac workload.
• Stable angina: provides long‑term symptom control by decreasing myocardial oxygen demand.

• 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, producing vasodilation, lowering preload and afterload, and consequently reducing myocardial oxygen consumption.

Adverse reactions may occur with any nitrate therapy.

Common Side Effects

• Headache: throbbing pain often occurring shortly after dosing.
• Dizziness or light‑headedness: related to blood pressure reduction.
• Flushing: warm sensation and reddening of the skin.
• Nausea: mild gastrointestinal upset.
• Hypotension: measurable drop in blood pressure.
• Palpitations: awareness of heartbeats.

Serious or Rare Side Effects

• Severe hypotension: may cause syncope or shock.
• Allergic reaction: rash, itching, swelling, or anaphylaxis.
• Methemoglobinemia: rare discoloration of blood causing cyanosis.
• Stevens‑Johnson syndrome: severe skin and mucous membrane involvement.
• Chest pain worsening: paradoxical increase in angina.

Before initiating therapy, clinicians should consider several safety measures.

• Cardiovascular assessment: evaluate baseline blood pressure and heart rate.
• Concomitant nitrate use: avoid combining with other nitrate preparations.
• PDE5 inhibitors: do not co‑administer with sildenafil, tadalafil, or similar agents.
• Renal impairment: adjust dosing or monitor closely in patients with reduced kidney function.
• Alcohol consumption: advise patients that alcohol may potentiate hypotensive effects.
• Store at room temperature: keep in the original container, protect from moisture and direct sunlight.

Isomex can interact with several drug classes, requiring vigilance.

Major Interactions (Avoid)

• Phosphodiesterase‑5 inhibitors (e.g., sildenafil, tadalafil): risk of profound hypotension.
• Other organic nitrates (e.g., nitroglycerin): additive vasodilatory effect leading to severe blood pressure fall.
• Guanylate cyclase stimulators (e.g., riociguat): may cause excessive vasodilation.

Moderate Interactions (Monitor Closely)

• Antihypertensive agents (ACE inhibitors, beta‑blockers): monitor blood pressure for additive effects.
• Diuretics: may enhance orthostatic hypotension.
• Alcohol: can increase the likelihood of dizziness and hypotension.