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Drugs, Supplies and Delivery
Ranolazine
Ranolazine is a unique anti-anginal medication used to treat chronic stable angina in patients who remain symptomatic despite standard therapies. Unlike traditional anti-anginal drugs, ranolazine does not significantly affect heart rate or blood pressure, making it a valuable option for patients with contraindications to other treatments. This article synthesizes information from the British National Formulary (BNF), Lippincott Textbook of Pharmacology, and Lange Basic & Clinical Pharmacology to provide a detailed overview of ranolazine, including its mechanism, uses, dosing, side effects, precautions, and drug interactions.
Ranolazine exerts its anti-anginal effects through the following mechanisms:
- Inhibition of Late Sodium Current:
- Ranolazine selectively inhibits the late sodium current in cardiac myocytes, reducing intracellular sodium overload. This indirectly decreases calcium overload via the Na-Ca exchanger, improving myocardial relaxation and reducing diastolic stiffness (Lippincott, Lange).
- Improved Myocardial Oxygen Supply-Demand Balance:
- By reducing diastolic tension and myocardial oxygen demand, ranolazine improves coronary blood flow and alleviates angina symptoms (BNF).
Ranolazine does not significantly affect heart rate or blood pressure, making it suitable for patients with bradycardia or hypotension (Lippincott).
- Chronic Stable Angina:
- Used as an adjunct to standard therapies (e.g., beta-blockers, calcium channel blockers, nitrates) in patients who remain symptomatic (BNF).
- Off-Label Uses:
- Investigated for use in atrial fibrillation and diastolic heart failure, though evidence is limited (Lange).
- Initial Dose: 500 mg twice daily, increased to 1000 mg twice daily if needed (max 1000 mg twice daily) (BNF).
- Administration:
- Take with or without food.
- Swallow extended-release tablets whole; do not crush or chew (Lippincott).
- Common: Dizziness, headache, constipation, and nausea (Lippincott).
- Serious: QT prolongation (rare), syncope, and acute kidney injury (Lange).
- QT Prolongation: Avoid in patients with pre-existing QT prolongation or those taking other QT-prolonging drugs (BNF).
- Liver Impairment: Contraindicated in patients with severe hepatic impairment (Child-Pugh Class C) (Lippincott).
- Renal Impairment: Use with caution in patients with moderate to severe renal impairment (eGFR <30 mL/min/1.73 m²) (Lange).
- Pregnancy: Use only if benefits outweigh risks; limited data available (BNF).
- CYP3A4 Inhibitors (e.g., ketoconazole, clarithromycin): Increase ranolazine levels, raising the risk of QT prolongation and toxicity (Lippincott).
- CYP3A4 Inducers (e.g., rifampin, phenytoin): Reduce ranolazine levels, decreasing efficacy (Lange).
- QT-Prolonging Drugs (e.g., amiodarone, sotalol): Increased risk of QT prolongation and arrhythmias (BNF).
- Digoxin: Ranolazine may increase digoxin levels; monitor digoxin levels closely (Lippincott).
Ranolazine is the generic name for this medication. It is marketed under the brand name Ranexa® (extended-release formulation). Generic versions are also available, making it more accessible for patients.
