What the FDA labels say about taking them together
Cobicistat and diltiazem
Cobicistat's FDA label of February 10, 2026 names diltiazem in its drug interactions section; the diltiazem labels PlainMeds reads (4) do not name cobicistat. The cobicistat label: “Clinical monitoring is recommended for coadministration with calcium channel blockers metabolized by CYP3A.”
Check it at the source: the cobicistat FDA label on DailyMed (effective February 10, 2026, Gilead Sciences, Inc.); the diltiazem FDA label on DailyMed (effective August 7, 2026, Bausch Health US, LLC).
What does the cobicistat label say about diltiazem?
Cobicistat label, drug interactionsConcomitant Drug Class/Drug Name: Calcium Channel Blockers: e.g., amlodipine diltiazem felodipine nifedipine verapamil; Potential Effect ↑ = Increase, ↓ = Decrease, ↔ = No change: ↑ calcium channel blockers; Clinical Comment: Clinical monitoring is recommended for coadministration with calcium channel blockers metabolized by CYP3A.
Source: FDA drug label (Tybost), Gilead Sciences, Inc., effective February 10, 2026 (SPL set 3784c35c-e87f-410c-900b-8fd6313c6010), via openFDA; the full label on DailyMed
What does the diltiazem label say about cobicistat?
Diltiazem's label (effective August 7, 2026) and its 3 other brand-application labels do not name cobicistat in these sections. A label lists what its studies and reports found; it is not a complete list.
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
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
| Cobicistat | Diltiazem | |
|---|---|---|
| Labeled for | HIV | High blood pressure, Angina, Atrial fibrillation |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | n/a | $0.144 per capsule 24h ER(cd) 120 mg capsule |
| Shortage now | A presentation being discontinued | A presentation being discontinued |
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