Simvastatin and pravastatin differ significantly in their metabolism, leading to varying drug interaction profiles. Simvastatin undergoes extensive hepatic metabolism via the cytochrome P450 (CYP) enzyme system, specifically CYP3A4 and CYP2C9. Pravastatin, conversely, undergoes minimal hepatic metabolism, primarily excreted unchanged in the bile.
Simvastatin Metabolism and Interactions
- CYP3A4 Inhibitors: Drugs like ketoconazole, erythromycin, and grapefruit juice strongly inhibit CYP3A4, increasing simvastatin levels and raising the risk of myopathy (muscle damage). Avoid concomitant use. CYP2C9 Inhibitors: Amiodarone and fluconazole inhibit CYP2C9, also increasing simvastatin levels. Monitor closely. CYP Inducers: Rifampin and St. John’s wort induce CYP enzymes, potentially decreasing simvastatin efficacy. Consider alternative statins or dosage adjustments.
Pravastatin Metabolism and Interactions
Due to its limited metabolism, pravastatin exhibits fewer clinically significant drug interactions. It’s generally considered safer for patients taking multiple medications.
Specific Recommendations
Always disclose all medications and supplements: This includes over-the-counter drugs and herbal remedies to your physician or pharmacist before starting simvastatin or pravastatin. Regular monitoring: For patients on simvastatin, particularly those also taking CYP3A4 or CYP2C9 inhibitors or inducers, regular monitoring of liver function and creatine kinase levels is advised. Individualized Approach: The choice between simvastatin and pravastatin should be tailored to the patient’s specific clinical circumstances, considering their medication profile and potential drug interactions.
Further Considerations
While pravastatin generally offers a simpler interaction profile, both drugs can interact with other medications. Consult detailed drug interaction databases for comprehensive information.
