What the FDA labels say about taking them together
Erythromycin and tamsulosin
Tamsulosin's FDA label of December 1, 2025 names erythromycin in its drug interactions section; the erythromycin labels PlainMeds reads (4) do not name tamsulosin. The tamsulosin label: “Tamsulosin hydrochloride capsules should be used with caution in combination with moderate inhibitors of CYP3A4 (e.g., erythromycin), in combination with strong (e.g., paroxetine) or moderate (e.g., terbinafine) …”
Check it at the source: the erythromycin FDA label on DailyMed (effective August 1, 2024, Teva Pharmaceuticals USA, Inc.); the tamsulosin FDA label on DailyMed (effective December 1, 2025, Synthon Pharmaceuticals, Inc.).
What does the erythromycin label say about tamsulosin?
Erythromycin's label (effective August 1, 2024) and its 3 other brand-application labels do 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 (Erythromycin), Teva Pharmaceuticals USA, Inc., effective August 1, 2024 (SPL set 75a0bd5a-d09f-483b-bfd8-f8343b149eb2), via openFDA; the full label on DailyMed
What does the tamsulosin label say about erythromycin?
Tamsulosin label, drug interactionsTamsulosin hydrochloride capsules should be used with caution in combination with moderate inhibitors of CYP3A4 (e.g., erythromycin), in combination with strong (e.g., paroxetine) or moderate (e.g., terbinafine) inhibitors of CYP2D6, or in patients known to be CYP2D6 poor metabolizers, particularly at a dose higher than 0.4 mg (e.g., 0.8 mg). ( 5.2 , 7.1 , 12.3 ) Concomitant use of PDE5 inhibitors with tamsulosin can potentially cause symptomatic hypotension
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
| Erythromycin | Tamsulosin | |
|---|---|---|
| Labeled for | Bacterial infections, Acne | Enlarged prostate (BPH) |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $1.96 per tablet 250 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