Masdil (Diltiazem Hydrochloride)

Diltiazem Hydrochloride is used to manage cardiovascular conditions that involve elevated vascular tone or myocardial oxygen demand.

• Hypertension: reduces systolic and diastolic blood pressure by relaxing arterial smooth muscle.
• Chronic stable angina: decreases myocardial oxygen demand, relieving chest pain during exertion.
• Angina pectoris: improves coronary blood flow to alleviate acute episodes of chest discomfort.
• Rate control in atrial fibrillation: slows atrioventricular nodal conduction to maintain a controlled ventricular rate.

• Diltiazem Hydrochloride blocks L‑type calcium channels in cardiac myocytes and vascular smooth‑muscle cells. By inhibiting calcium influx, it reduces myocardial contractility and slows conduction through the atrioventricular node, while causing vasodilation of peripheral arteries. The combined negative inotropic, chronotropic and vasodilatory actions lower heart rate and systemic blood pressure.

Diltiazem Hydrochloride may be associated with a range of adverse reactions, varying from mild to serious.

Common Side Effects

• Headache: mild to moderate headache often reported during initiation.
• Peripheral edema: swelling of ankles or lower legs due to vasodilation.
• Flushing: transient warmth and redness of the skin.
• Dizziness or light‑headedness: especially when standing quickly.

Serious or Rare Side Effects

• Bradycardia: abnormally low heart rate requiring medical attention.
• Heart block: impairment of electrical conduction that may necessitate pacemaker.
• Severe hypotension: marked drop in blood pressure leading to fainting or shock.

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

• Assess cardiovascular status: evaluate heart rate, blood pressure and conduction abnormalities before initiating therapy.
• Monitor liver function: dose adjustments may be needed in hepatic impairment.
• Avoid in severe heart failure: risk of worsening cardiac output.
• Caution with concomitant beta‑blockers: may cause excessive bradycardia or AV block.
• Pregnancy and lactation: use only if potential benefit justifies potential risk, as safety data are limited.
• Store at ambient temperature: keep below 25 °C in the original container, protect from moisture and light.

Diltiazem Hydrochloride interacts with several medicines that can alter its efficacy or safety.

Major Interactions (Avoid)

• Concurrent use with strong CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin): may markedly increase diltiazem plasma levels.
• Co‑administration with other non‑dihydropyridine calcium channel blockers: additive negative inotropic and chronotropic effects.
• Combination with beta‑blockers in patients with conduction disease: risk of severe bradycardia or heart block.

Moderate Interactions (Monitor Closely)

• CYP3A4 inducers (e.g., rifampin, carbamazepine): may reduce therapeutic effectiveness.
• Digoxin: diltiazem can increase digoxin concentrations, requiring serum level monitoring.