What the FDA labels say about taking them together
Cimetidine and tamsulosin
Tamsulosin's FDA label of December 1, 2025 names cimetidine in its drug interactions section; the cimetidine label PlainMeds reads does not name tamsulosin. The tamsulosin label: “Tamsulosin hydrochloride capsules should be used with caution in combination with cimetidine, particularly at a dose higher than 0.4 mg (e.g., 0.8 mg).”
Check it at the source: the cimetidine FDA label on DailyMed (effective July 15, 2026, Mylan Pharmaceuticals Inc.); the tamsulosin FDA label on DailyMed (effective December 1, 2025, Synthon Pharmaceuticals, Inc.).
What does the cimetidine label say about tamsulosin?
Cimetidine's label (effective July 15, 2026) does not name tamsulosin 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 tamsulosin label say about cimetidine?
Tamsulosin label, drug interactionsCimetidine Treatment with cimetidine resulted in a significant decrease (26%) in the clearance of tamsulosin hydrochloride, which resulted in a moderate increase in tamsulosin hydrochloride AUC (44%) [see Warnings and Precautions (5.2) and Clinical Pharmacology (12.3) ].
Tamsulosin label, warnings and precautionsTamsulosin hydrochloride capsules should be used with caution in combination with cimetidine, particularly at a dose higher than 0.4 mg (e.g., 0.8 mg) [see Drug Interactions (7.1) and Clinical Pharmacology (12.3) ].
Source: FDA drug label (Tamsulosin hydrochloride), Synthon Pharmaceuticals, Inc., effective December 1, 2025 (SPL set 13a5032d-0be1-4001-916e-459f0b1a051d), 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 | Tamsulosin | |
|---|---|---|
| Labeled for | Acid reflux and ulcers | Enlarged prostate (BPH) |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.236 per tablet 300 mg tablet | $0.05 per capsule 0.4 mg capsule |
| 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