Drug interactions
Dapsone + Efavirenz
Severity: Moderate
Dapsone and Efavirenz: 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
Efavirenz induces CYP3A4 and may lower dapsone concentrations, which could reduce prophylactic efficacy. Induction might also increase formation of reactive hydroxylamine metabolites.
What this interaction means in plain words
Dapsone and Efavirenz 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; Efavirenz belongs to Anti Virals.
Why it happens
CYP3A4 induction by efavirenz increases dapsone metabolism.
What to do
Monitor clinical response and haemoglobin or methaemoglobin levels; consider alternative PCP prophylaxis if failure is a concern.
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 Efavirenz
- Cobimetinib + Efavirenz Contraindicated
- Dienogest / estradiol valerate + Efavirenz Contraindicated
- Dihydroergotamine intranasal + Efavirenz Contraindicated
- Dihydroergotamine + Efavirenz Contraindicated
- Doravirine + Efavirenz Contraindicated
- Efavirenz + Elbasvir / grazoprevir Contraindicated
Frequently asked questions
Can I take Dapsone with Efavirenz?
MediHelp rates the interaction as moderate. Dapsone and Efavirenz 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. Efavirenz induces CYP3A4 and may lower dapsone concentrations, which could reduce prophylactic efficacy. Induction might also increase formation of reactive hydroxylamine metabolites.
How serious is the interaction between Dapsone and Efavirenz?
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 clinical response and haemoglobin or methaemoglobin levels; consider alternative PCP prophylaxis if failure is a concern.
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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