Drug interactions
Dapsone + Pyrimethamine
Severity: Moderate
Dapsone and Pyrimethamine: 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
Dapsone and pyrimethamine are used together for toxoplasmosis and malaria prophylaxis, but both can cause hematologic toxicity. Pyrimethamine is an antifolate that can cause bone marrow suppression, and dapsone can cause hemolysis and methemoglobinemia. The combination increases the risk of anemia, neutropenia and thrombocytopenia.
What this interaction means in plain words
Dapsone and Pyrimethamine 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; Pyrimethamine belongs to Anti Parasitic.
Why it happens
Additive hematologic toxicity: antifolate marrow suppression from pyrimethamine plus oxidative hemolysis from dapsone.
What to do
Screen for G6PD deficiency and monitor complete blood counts regularly. Give folinic acid with pyrimethamine as recommended in treatment protocols.
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 Pyrimethamine
- Deferiprone + Pyrimethamine Major
- Eliglustat + Pyrimethamine Major
- Acalabrutinib + Pyrimethamine Moderate
- Brexpiprazole + Pyrimethamine Moderate
- Folic acid + Pyrimethamine Moderate
- Fosphenytoin + Pyrimethamine Moderate
Frequently asked questions
Can I take Dapsone with Pyrimethamine?
MediHelp rates the interaction as moderate. Dapsone and Pyrimethamine 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 and pyrimethamine are used together for toxoplasmosis and malaria prophylaxis, but both can cause hematologic toxicity. Pyrimethamine is an antifolate that can cause bone marrow suppression, and dapsone can cause hemolysis and methemoglobinemia. The combination increases the risk of anemia, neutropenia and thrombocytopenia.
How serious is the interaction between Dapsone and Pyrimethamine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Screen for G6PD deficiency and monitor complete blood counts regularly. Give folinic acid with pyrimethamine as recommended in treatment protocols.
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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