Learning Objective:

Understand the mechanism of action, clinical uses, side effects, and contraindications of ranolazine in cardiac patients.

Mechanism of Action

• Primary effect:
  Blocks late inward Na⁺ current in cardiac myocytes → ↓ intracellular Na⁺ → ↓ Ca²⁺ accumulation → reduces myocardial oxygen demand.
• Secondary effect: Mild K⁺ channel blockade affecting repolarization.

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Clinical Effects / Use

• Used mainly for chronic stable angina.
• Improves symptoms without significantly affecting heart rate or blood pressure.

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Side Effects

• Most common: constipation, nausea
• Other: QT interval prolongation → risk of arrhythmias

 Contraindications

• Congenital long QT syndrome
• Concurrent use of drugs that increase the QT interval
• Clinical pearl: Check electrolytes (Mg²⁺, K⁺) before therapy.

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High-Yield Summary Table

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