What the FDA labels say about taking them together
Diltiazem and simvastatin
Diltiazem's FDA label of August 7, 2026 names simvastatin in its drug interactions section, and simvastatin's label names diltiazem too. The simvastatin label: “The risk of myopathy and rhabdomyolysis is increased by concomitant use of amiodarone, dronedarone, ranolazine, or calcium channel blockers with ZOCOR.”
Check it at the source: the diltiazem FDA label on DailyMed (effective August 7, 2026, Bausch Health US, LLC); the simvastatin FDA label on DailyMed (effective March 28, 2025, Organon LLC).
What does the diltiazem label say about simvastatin?
Diltiazem label, drug interactionsIn a healthy volunteer cross-over study (N=10), coadministration of a single 20 mg dose of simvastatin at the end of a 14-day regimen with 120 mg BID diltiazem SR resulted in a 5-fold increase in mean simvastatin AUC versus simvastatin alone.
Source: FDA drug label (Cardizem Cd, NDA020062), Bausch Health US LLC, effective December 10, 2025 (SPL set 1042fa13-e6af-46b9-8008-6c941f0978b1), via openFDA
Source: FDA drug label (TIAZAC EXTENDED RELEASE), Bausch Health US, LLC, effective August 7, 2026 (SPL set c567fe7e-887e-4291-a0d1-2dd3f25cbf25), via openFDA; the full label on DailyMed
What does the simvastatin label say about diltiazem?
Simvastatin label, drug interactionsAmiodarone, Dronedarone, Ranolazine, or Calcium Channel Blockers Clinical Impact: The risk of myopathy and rhabdomyolysis is increased by concomitant use of amiodarone, dronedarone, ranolazine, or calcium channel blockers with ZOCOR. Intervention: For patients taking verapamil, diltiazem, or dronedarone, do not exceed ZOCOR 10 mg daily. For patients taking amiodarone, amlodipine, or ranolazine, do not exceed ZOCOR 20 mg daily [see ].
Simvastatin label, warnings and precautionsZOCOR dosage modifications are recommended for patients taking lomitapide, verapamil, diltiazem, dronedarone, amiodarone, amlodipine or ranolazine [see Dosage and Administration (2.5) ].
Source: FDA drug label (ZOCOR), Organon LLC, effective March 28, 2025 (SPL set 8f55d5de-5a4f-4a39-8c84-c53976dd6af9), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Diltiazem | Simvastatin | |
|---|---|---|
| Labeled for | High blood pressure, Angina, Atrial fibrillation | Heart attack and coronary artery disease, High cholesterol, High triglycerides |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.144 per capsule 24h ER(cd) 120 mg capsule | $0.0321 per tablet 20 mg tablet |
| Shortage now | A presentation being discontinued | No current entry |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once