What the FDA labels say about taking them together
Digoxin and sulfamethoxazole/trimethoprim
Sulfamethoxazole/trimethoprim's FDA label of December 30, 2024 names digoxin in its drug interactions section; the digoxin labels PlainMeds reads (3) do not name sulfamethoxazole/trimethoprim. The sulfamethoxazole/trimethoprim label: “Increased digoxin blood levels can occur with concomitant sulfamethoxazole and trimethoprim therapy, especially in elderly patients.”
Check it at the source: the digoxin FDA label on DailyMed (effective December 5, 2024, Advanz Pharma (US) Corp.); the sulfamethoxazole/trimethoprim FDA label on DailyMed (effective December 30, 2024, Sun Pharmaceutical Industries, Inc).
What does the digoxin label say about sulfamethoxazole/trimethoprim?
Digoxin's label (effective December 5, 2024) and its 2 other brand-application labels do not name sulfamethoxazole/trimethoprim in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (LANOXIN), Advanz Pharma (US) Corp., effective December 5, 2024 (SPL set d91e3646-4c63-4512-ab22-db39c085c4dc), via openFDA; the full label on DailyMed
What does the sulfamethoxazole/trimethoprim label say about digoxin?
Sulfamethoxazole/trimethoprim label, drug interactionsDigoxin Monitor serum digoxin levels Increased digoxin blood levels can occur with concomitant BACTRIM therapy, especially in elderly patients.
Sulfatrim label (Preferred Pharmaceuticals, Inc., September 2, 2026), drug interactionsIncreased digoxin blood levels can occur with concomitant sulfamethoxazole and trimethoprim therapy, especially in elderly patients.
Source: FDA drug label (Sulfatrim, NDA018615), Preferred Pharmaceuticals, Inc., effective September 2, 2026 (SPL set cd4932ce-0856-4e99-8baf-70afce1d7ffd), via openFDA
Source: FDA drug label (Bactrim), Sun Pharmaceutical Industries, Inc, effective December 30, 2024 (SPL set f59d0c04-9c66-4d53-a0e1-cb55570deb62), 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
| Digoxin | Sulfamethoxazole/trimethoprim | |
|---|---|---|
| Labeled for | Heart failure, Atrial fibrillation | Bacterial infections, Urinary tract infections, Diarrhea |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.133 per tablet 125 mcg tablet | $0.0448 per tablet Sulfamethoxazole-tmp ds 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