What the FDA labels say about taking them together
Cimetidine and doxazosin
Doxazosin's FDA label of October 15, 2023 names cimetidine in its drug interactions section; the cimetidine label PlainMeds reads does not name doxazosin. The doxazosin label: “In healthy volunteers, the administration of a single 1 mg dose of doxazosin on day 1 of a four-day regimen of oral cimetidine (400 mg twice daily) resulted in a 10% increase in mean AUC of doxazosin, and a slight but …”
Check it at the source: the cimetidine FDA label on DailyMed (effective July 15, 2026, Mylan Pharmaceuticals Inc.); the doxazosin FDA label on DailyMed (effective October 15, 2023, Viatris Specialty LLC).
What does the cimetidine label say about doxazosin?
Cimetidine's label (effective July 15, 2026) does not name doxazosin in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Cimetidine), Mylan Pharmaceuticals Inc., effective July 15, 2026 (SPL set 06c0a509-026f-44e0-9975-a94a8de51d43), via openFDA; the full label on DailyMed
What does the doxazosin label say about cimetidine?
Doxazosin label, drug interactionsIn healthy volunteers, the administration of a single 1 mg dose of doxazosin on day 1 of a four-day regimen of oral cimetidine (400 mg twice daily) resulted in a 10% increase in mean AUC of doxazosin, and a slight but not significant increase in mean C max and mean half-life of doxazosin.
Source: FDA drug label (Cardura), Viatris Specialty LLC, effective October 15, 2023 (SPL set 5e1f5e49-2da1-43ab-9795-228a8bcc5a82), 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
| Cimetidine | Doxazosin | |
|---|---|---|
| Labeled for | Acid reflux and ulcers | Enlarged prostate (BPH), High blood pressure |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.236 per tablet 300 mg tablet | $0.0752 per tablet 1 mg tablet |
| Shortage now | No current entry | 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