Isoptin Sr-E 240 (Verapamil Hydrochloride)

Verapamil Hydrochloride acts on cardiovascular smooth muscle and cardiac conduction pathways, providing therapeutic benefit in several heart‑related conditions.

• Hypertension: lowers blood pressure by reducing peripheral vascular resistance.
• Angina pectoris: alleviates chest pain by decreasing myocardial oxygen demand through vasodilation.
• Supraventricular tachycardia: slows atrioventricular nodal conduction to control rapid heart rates.
• Other cardiac arrhythmias: stabilises abnormal rhythms by modulating calcium influx in cardiac cells.

• Verapamil Hydrochloride blocks L‑type calcium channels in cardiac myocytes and vascular smooth muscle, reducing calcium entry. This leads to decreased myocardial contractility, slowed atrioventricular nodal conduction, and vasodilation of peripheral arteries, collectively lowering blood pressure and myocardial oxygen consumption.

Adverse reactions may vary in frequency and severity.

Common Side Effects

• Constipation: mild to moderate difficulty passing stool.
• Dizziness: sensation of light‑headedness, especially on standing.
• Headache: transient cranial discomfort.
• Flushing: warm sensation with reddening of the skin.

Serious or Rare Side Effects

• Bradycardia: abnormally slow heart rate requiring medical attention.
• Hypotension: significant drop in blood pressure that may cause fainting.
• AV block: impaired atrioventricular conduction that can lead to heart block.

Before initiating therapy, clinicians should consider several safety aspects.

• Monitor blood pressure: ensure adequate control and avoid excessive hypotension.
• Assess cardiac function: evaluate for existing heart failure or conduction disorders.
• Review concomitant beta‑blocker use: combined effects may cause severe bradycardia.
• Avoid abrupt discontinuation: tapering reduces risk of rebound hypertension.
• Adjust dose in hepatic impairment: impaired metabolism may increase drug exposure.
• Store at room temperature: keep in the original container, protect from moisture and direct sunlight.

Verapamil may interact with several medicines, altering efficacy or safety.

Major Interactions (Avoid)

• Beta‑blockers: combined use can cause profound bradycardia and AV block.
• Digoxin: verapamil raises digoxin plasma levels, increasing toxicity risk.

Moderate Interactions (Monitor Closely)

• Diltiazem: additive effects on cardiac conduction and contractility.
• CYP3A4 inhibitors (e.g., erythromycin, clarithromycin): may increase verapamil concentrations.
• Statins (e.g., simvastatin, lovastatin): elevated risk of statin‑related myopathy.