Ivabradine Viatris (Ivabradine Oxalate)

Ivabradine acts on the cardiac sinus node to reduce heart rate, benefiting conditions where excessive heart rate contributes to symptoms.

• Chronic stable angina: improves exercise tolerance and reduces frequency of angina episodes.
• Heart failure with reduced ejection fraction: lowers heart rate, helping to improve functional capacity and reduce hospitalization risk.

• Ivabradine selectively inhibits the funny (If) current in the sinoatrial node by binding to the HCN channel pore. This reduces spontaneous depolarisation, leading to a slower heart rate without affecting myocardial contractility or ventricular repolarisation, thereby decreasing myocardial oxygen demand.

Ivabradine may cause a range of adverse reactions, most of which are dose‑related and reversible.

Common Side Effects

• Bradycardia: heart rate falls below the intended therapeutic range.
• Visual disturbances (phosphenes): transient luminous phenomena, especially in low‑light conditions.
• Headache: mild to moderate intensity, often early in treatment.
• Dizziness: may accompany reduced heart rate.
• Fatigue: general feeling of tiredness.

Serious or Rare Side Effects

• Symptomatic bradycardia requiring medical intervention.
• Atrial fibrillation or other supraventricular arrhythmias.
• Severe hypotension leading to syncope.
• Persistent visual loss or retinal disturbances.
• QT‑interval prolongation in susceptible individuals.

Before initiating therapy, clinicians should assess individual risk factors and monitor patients closely.

• Heart rate monitoring: ensure resting heart rate remains above 50 bpm before dose escalation.
• Severe hepatic impairment: avoid or use with extreme caution.
• Sick sinus syndrome or atrioventricular block: contraindicated.
• Concomitant strong CYP3A4 inhibitors: avoid due to increased plasma levels.
• Pregnancy and lactation: safety not established; use only if potential benefit outweighs risk.
• Store at below 25°C: keep in the original packaging, protect from moisture and direct sunlight.

Ivabradine's pharmacokinetics can be altered by several co‑administered medicines.

Major Interactions (Avoid)

• Strong CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin): markedly increase ivabradine exposure.
• Other bradycardic agents (beta‑blockers, digoxin): may cause excessive heart‑rate reduction.
• Certain anti‑arrhythmic drugs (e.g., amiodarone): increase risk of atrial fibrillation.

Moderate Interactions (Monitor Closely)

• Moderate CYP3A4 inhibitors (e.g., diltiazem, verapamil): may require dose adjustment.
• CYP3A4 substrates (e.g., statins): monitor for altered plasma concentrations.
• Drugs that affect electrolyte balance (e.g., diuretics): watch for additive hypotensive effects.