What the FDA labels say about taking them together
Dapsone and sulfamethoxazole/trimethoprim
Dapsone's FDA label (Aczone) of October 23, 2025 names sulfamethoxazole/trimethoprim in its drug interactions section; the sulfamethoxazole/trimethoprim labels PlainMeds reads (2) do not name dapsone. The dapsone label: “Trimethoprim/sulfamethoxazole (TMP/SMX) increases the systemic level of dapsone and its metabolites.”
Check it at the source: the dapsone FDA label on DailyMed (effective July 20, 2026, Macleods Pharmaceuticals Limited); the sulfamethoxazole/trimethoprim FDA label on DailyMed (effective December 30, 2024, Sun Pharmaceutical Industries, Inc).
What does the dapsone label say about sulfamethoxazole/trimethoprim?
Aczone label (Almirall, LLC, October 23, 2025), drug interactionsTrimethoprim/sulfamethoxazole (TMP/SMX) increases the systemic level of dapsone and its metabolites ( 7.1 ).
Aczone label (Almirall, LLC, October 23, 2025), warnings and precautionsCombination of ACZONE Gel, 7.5%, with trimethoprim/sulfamethoxazole (TMP/SMX) may increase the likelihood of hemolysis in patients with G6PD deficiency [see Drug Interactions ( 7.1 )].
Source: FDA drug label (Aczone, NDA207154), Almirall, LLC, effective October 23, 2025 (SPL set 22058b7d-a578-4eaa-a476-ac982337f02a), via openFDA
Source: FDA drug label (Dapsone, NDA021794), Pacific Pharma, Inc., effective September 30, 2018 (SPL set 8dbe1a41-6d9d-414f-aa9c-09bd95857e2a), via openFDA
Source: FDA drug label (Dapsone), Macleods Pharmaceuticals Limited, effective July 20, 2026 (SPL set 839d7440-ba0e-4c56-b648-d374b155cf03), via openFDA; the full label on DailyMed
What does the sulfamethoxazole/trimethoprim label say about dapsone?
Sulfamethoxazole/trimethoprim's label (effective December 30, 2024) and its 1 other brand-application label do not name dapsone in these sections. A label lists what its studies and reports found; it is not a complete list.
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
| Dapsone | Sulfamethoxazole/trimethoprim | |
|---|---|---|
| Labeled for | Acne | Bacterial infections, Urinary tract infections, Diarrhea |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.664 per gram 5% gel | $0.0448 per tablet Sulfamethoxazole-tmp ds tablet |
| Shortage now | A presentation being discontinued | 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