What the FDA labels say about taking them together
Tamsulosin and theophylline
Tamsulosin's FDA label of December 1, 2025 names theophylline in its drug interactions section; the theophylline label PlainMeds reads does not name tamsulosin. The tamsulosin label: “Dosage adjustments are not necessary when a tamsulosin hydrochloride capsule is administered concomitantly with digoxin or theophylline.”
Check it at the source: the tamsulosin FDA label on DailyMed (effective December 1, 2025, Synthon Pharmaceuticals, Inc.); the theophylline FDA label on DailyMed (effective March 10, 2026, Strides Pharma Science Limited).
What does the tamsulosin label say about theophylline?
Tamsulosin label, drug interactionsDosage adjustments are not necessary when a tamsulosin hydrochloride capsule is administered concomitantly with digoxin or theophylline [see 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
What does the theophylline label say about tamsulosin?
Theophylline's label (effective March 10, 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 (Theophylline), Strides Pharma Science Limited, effective March 10, 2026 (SPL set b7a90ccf-9c32-40cc-9008-7e55b3da4dfd), 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
| Tamsulosin | Theophylline | |
|---|---|---|
| Labeled for | Enlarged prostate (BPH) | Asthma |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.05 per capsule 0.4 mg capsule | $0.330 per tablet 300 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