Drug interactions
Dapsone + Trimethoprim
Severity: Moderate
Dapsone and Trimethoprim: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Co-administration, as used for Pneumocystis pneumonia treatment, raises concentrations of both drugs. This may increase adverse effects such as methemoglobinemia or hematologic toxicity from dapsone and trimethoprim-related effects.
What this interaction means in plain words
Dapsone and Trimethoprim can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Dapsone belongs to Anti Bacterial; Trimethoprim belongs to Anti Bacterial.
Why it happens
Mutual inhibition of elimination is suggested, but the precise mechanism is not firmly established.
What to do
Monitor complete blood count and methemoglobin or symptoms of hypoxia during combined therapy. Check potassium and renal function with trimethoprim.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Dapsone
- Bcg vaccine live + Dapsone Major
- Dapsone + Primaquine Major
- Apalutamide + Dapsone Moderate
- Belzutifan + Dapsone Moderate
- Bosentan + Dapsone Moderate
- Bupivacaine implant + Dapsone Moderate
Other interactions of Trimethoprim
Frequently asked questions
Can I take Dapsone with Trimethoprim?
MediHelp rates the interaction as moderate. Dapsone and Trimethoprim can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Co-administration, as used for Pneumocystis pneumonia treatment, raises concentrations of both drugs. This may increase adverse effects such as methemoglobinemia or hematologic toxicity from dapsone and trimethoprim-related effects.
How serious is the interaction between Dapsone and Trimethoprim?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor complete blood count and methemoglobin or symptoms of hypoxia during combined therapy. Check potassium and renal function with trimethoprim.
What other medicines interact with Dapsone?
MediHelp also lists interactions of Dapsone with, for example, Bcg vaccine live, Primaquine, Apalutamide. The full list is on the Dapsone page.
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