What the FDA labels say about taking them together
Atazanavir and diltiazem
Atazanavir's FDA label of August 6, 2025 names diltiazem in its drug interactions section; the diltiazem labels PlainMeds reads (4) do not name atazanavir. The atazanavir label: “Caution is warranted. A dose reduction of diltiazem by 50% should be considered. ECG monitoring is recommended. Coadministration of diltiazem and atazanavir with ritonavir has not been studied.”
Check it at the source: the atazanavir FDA label on DailyMed (effective August 6, 2025, Aurobindo Pharma Limited); the diltiazem FDA label on DailyMed (effective August 7, 2026, Bausch Health US, LLC).
What does the atazanavir label say about diltiazem?
Atazanavir label, drug interactionsConcomitant Drug Class/Specific Drugs: Calcium channel blockers: diltiazem; Effect on Concentration of Atazanavir or Concomitant Drug: ↑ diltiazem and desacetyl- diltiazem; Clinical Comment: Caution is warranted. A dose reduction of diltiazem by 50% should be considered. ECG monitoring is recommended. Coadministration of diltiazem and atazanavir with ritonavir has not been studied.
Source: FDA drug label (Atazanavir Sulfate), Aurobindo Pharma Limited, effective August 6, 2025 (SPL set 7fbea274-d6b5-4faa-bbf0-05fefab42114), via openFDA; the full label on DailyMed
What does the diltiazem label say about atazanavir?
Diltiazem's label (effective August 7, 2026) and its 3 other brand-application labels do not name atazanavir 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
| Atazanavir | Diltiazem | |
|---|---|---|
| Labeled for | HIV | High blood pressure, Angina, Atrial fibrillation |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $2.23 per capsule 300 mg capsule | $0.144 per capsule 24h ER(cd) 120 mg capsule |
| Shortage now | No current entry | 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