Ivabradine Mercury Pharmaceuticals (Ivabradine)

Ivabradine acts on cardiac rhythm disorders and angina by selectively inhibiting the If current in the sino‑atrial node.

• Chronic heart failure: reduces heart rate, improving symptoms and exercise tolerance.
• Stable angina pectoris: lowers heart rate, decreasing frequency of angina attacks.

• Ivabradine selectively binds to the pacemaker (If) channels in the sino‑atrial node, inhibiting the inward mixed sodium–potassium current that drives spontaneous depolarisation. By reducing this funny current, the drug slows the slope of phase 4 depolarisation, leading to a decrease in heart rate without affecting myocardial contractility or ventricular repolarisation.

Ivabradine may cause a range of adverse reactions, which are classified by frequency and severity.

Common Side Effects

• Bradycardia: heart rate falls below the intended therapeutic range.
• Visual disturbances (phosphenes): transient luminous phenomena.
• Headache: mild to moderate intensity.
• Dizziness or vertigo: especially on standing.
• Fatigue: generalised tiredness.
• Blurred vision: temporary visual acuity changes.

Serious or Rare Side Effects

• Symptomatic bradycardia requiring medical intervention.
• Atrial fibrillation or other serious arrhythmias.
• Severe hypotension leading to syncope.
• Myocardial infarction in high‑risk patients.
• Significant hepatic dysfunction.
• Persistent visual impairment.

When prescribing ivabradine, clinicians should consider several precautionary measures to ensure patient safety.

• Cardiovascular assessment: evaluate baseline heart rate and rhythm before initiation.
• Concomitant bradycardic agents: monitor for excessive heart‑rate reduction when used with beta‑blockers or digoxin.
• CYP3A4 inhibitors: avoid strong inhibitors or adjust dose as needed.
• Pregnancy and lactation: safety not established; use only if benefit outweighs potential risk.
• Hepatic or renal impairment: use with caution and consider dose adjustment.
• Store at below 25°C: keep in the original packaging, protect from moisture and direct sunlight.

Ivabradine can interact with other medicines, influencing its plasma concentration or additive cardiac effects.

Major Interactions (Avoid)

• Strong CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin): may markedly increase ivabradine levels.
• Other heart‑rate lowering agents (beta‑blockers, digoxin, diltiazem, verapamil): risk of profound bradycardia.
• Concomitant use with other anti‑anginal drugs that affect conduction.

Moderate Interactions (Monitor Closely)

• Moderate CYP3A4 inhibitors (e.g., fluconazole, erythromycin): may require dose adjustment.
• Antihypertensive agents: monitor blood pressure for additive effects.
• Diuretics: watch for electrolyte disturbances that could affect cardiac rhythm.