Ranolazine

688

Summary

Ranolazine is used to treat refractory angina when other therapies have proven ineffective. It does this by inhibiting the late phase of the inward sodium current, thus reducing intracellular concentrations of both sodium and calcium ions and effectively reducing myocardial wall tension and oxygen consumption. Adverse effects are nonspecific, and ones commonly seen include dizziness, constipation, nausea. Very rarely is QT interval prolongation observed.

Key Points

  • Ranolazine
    • Mechanism
      • Inhibits sodium (Na+) current
        • Inhibits late phase of sodium → reduced Na+ → reduced Na+/Ca+ exchange → reduced Ca+ inside cell → decreases diastolic wall tension and oxygen consumption
        • Does not affect heart rate or blood pressure
    • Clinical Use
      • Refractory angina
        • Used in angina not controlled by medication, stenting, or bypass surgery
    • Adverse Effects
      • Nonspecific findings: constipation, dizziness, headache, nausea
      • QT prolongation (Torsades de Pointes risk)
        • Rare finding caused by higher doses, where drug inhibits potassium repolarization current