Diltiazem and Simvastatin: Drug Interaction Guide
Quick answer: This is a major interaction — avoid combining Diltiazem and Simvastatin unless specifically directed by your doctor.
How Diltiazem interacts with Simvastatin
Diltiazem inhibits CYP3A4 metabolism of simvastatin, increasing exposure and risk of myopathy and rhabdomyolysis.
What you should do
Limit simvastatin dose to 10 mg/day with diltiazem, or switch to pravastatin, rosuvastatin, or fluvastatin which are not significantly metabolized by CYP3A4.
Key facts
Severity
Major — avoid combination
Mechanism
Diltiazem inhibits CYP3A4 metabolism of simvastatin, increasing exposure and risk of myopathy and rhabdomyolysis.
Action
Limit simvastatin dose to 10 mg/day with diltiazem, or switch to pravastatin, rosuvastatin, or fluvastatin which are not...
Frequently asked questions
Can I take Diltiazem and Simvastatin together?
No — this combination should generally be avoided. Limit simvastatin dose to 10 mg/day with diltiazem, or switch to pravastatin, rosuvastatin, or fluvastatin which are not significantly metabolized by CYP3A4.
What is the severity of this interaction?
The interaction between Diltiazem and Simvastatin is classified as Major — avoid combination. Diltiazem inhibits CYP3A4 metabolism of simvastatin, increasing exposure and risk of myopathy and rhabdomyolysis.
What should I do if I'm prescribed both?
Limit simvastatin dose to 10 mg/day with diltiazem, or switch to pravastatin, rosuvastatin, or fluvastatin which are not significantly metabolized by CYP3A4. Always consult your prescribing clinician — do not stop or change medications without medical guidance.
Last reviewed: by iMedic Medical Editorial Team. Our editorial process.