What is the appropriate starting and maintenance dose of ranolazine, including adjustments for CYP3A inhibitors and renal or hepatic impairment?

Ranolazine Dosing

Start ranolazine at 500 mg twice daily and titrate to 1000 mg twice daily based on clinical response, with dose reductions required for moderate CYP3A inhibitors (maximum 500 mg twice daily) and contraindication with strong CYP3A inhibitors. 1

Initial Dosing

• Starting dose: 500 mg orally twice daily
• Maintenance dose: 1000 mg orally twice daily (maximum recommended dose)
• Titration: Increase from 500 mg to 1000 mg twice daily as needed based on anginal symptoms
• Administration: Take with or without food; swallow tablets whole—do not crush, break, or chew 1

Critical Dose Adjustments

CYP3A Inhibitor Interactions

Moderate CYP3A inhibitors:

• Maximum dose: 500 mg twice daily (do not exceed)
• Applies to: diltiazem, verapamil, erythromycin, fluconazole, grapefruit juice 1
• Clinical studies show diltiazem increases ranolazine exposure 1.5-fold, while verapamil approximately doubles exposure 2, 3

Strong CYP3A inhibitors:

• Contraindicated—do not use ranolazine
• Includes: ketoconazole, itraconazole, clarithromycin, nefazodone, nelfinavir, ritonavir, indinavir, saquinavir 1
• Ketoconazole increases ranolazine exposure 3.9-fold 2, 3

CYP3A inducers:

• Contraindicated—do not use ranolazine
• Includes: rifampin, rifabutin, rifapentine, phenobarbital, phenytoin, carbamazepine, St. John's wort 1

P-glycoprotein Inhibitors

• Cyclosporine and other P-gp inhibitors: Titrate ranolazine dose based on clinical response (may increase ranolazine concentrations) 1

Renal Impairment

No specific dose adjustment recommended in FDA labeling, but use with caution:

• Ranolazine AUC increases up to 2-fold with advancing renal impairment 2
• Mild impairment: 1.72-fold increase in exposure
• Moderate impairment: 1.80-fold increase
• Severe impairment: 1.97-fold increase 4
• Monitor closely: More marked increases in serum creatinine with BUN or potassium elevations indicating acute renal failure have been reported in severe renal impairment 1
• Less than 7% excreted unchanged renally, so factors beyond reduced GFR contribute to increased exposure 4

Hepatic Impairment

Contraindicated in hepatic impairment or liver cirrhosis 5

• Ranolazine is extensively metabolized by hepatic CYP3A enzymes 2
• Contraindication relates to risk of drug accumulation and dose-dependent QT prolongation 5

Important Drug Interactions Requiring Dose Adjustments of Other Medications

• Simvastatin: Limit to 20 mg once daily when co-administered with any dose of ranolazine 1
• Digoxin: May require dose reduction (ranolazine increases digoxin exposure 40-60% via P-gp inhibition) 1, 2
• Metformin: When using ranolazine 1000 mg twice daily, limit metformin to maximum 1700 mg/day and monitor glucose levels 1
• CYP2D6 substrates: Tricyclic antidepressants and antipsychotics may require lower doses 1

Clinical Context

The extended-release formulation of 500-1000 mg twice daily effectively reduces chronic stable angina symptoms with a neutral hemodynamic profile (no effect on heart rate or blood pressure), making it particularly useful in patients with bradycardia or hypotension 5. However, ranolazine does not improve cardiovascular outcomes (death, MI, or need for revascularization) in chronic stable angina patients 5.