Drug interactions
Clozapine + Sulfamethoxypyridazine
Severity: Moderate
Clozapine and Sulfamethoxypyridazine: 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
Sulfonamides can rarely cause neutropenia or agranulocytosis, which is also the key hematologic risk of clozapine. Combining them may increase the chance of serious bone marrow suppression.
What this interaction means in plain words
Clozapine and Sulfamethoxypyridazine 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.
Why it happens
Additive myelotoxic potential; no pharmacokinetic mechanism is established.
What to do
Monitor absolute neutrophil count more closely during sulfonamide use and choose a non-myelotoxic antibiotic if feasible.
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 Clozapine
- Clozapine + Deferiprone Contraindicated
- Clozapine + Irinotecan Contraindicated
- Clozapine + Pimozide Contraindicated
- Clozapine + Thioridazine Contraindicated
- Acalabrutinib + Clozapine Major
- Adagrasib + Clozapine Major
Frequently asked questions
Can I take Clozapine with Sulfamethoxypyridazine?
MediHelp rates the interaction as moderate. Clozapine and Sulfamethoxypyridazine 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. Sulfonamides can rarely cause neutropenia or agranulocytosis, which is also the key hematologic risk of clozapine. Combining them may increase the chance of serious bone marrow suppression.
How serious is the interaction between Clozapine and Sulfamethoxypyridazine?
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 absolute neutrophil count more closely during sulfonamide use and choose a non-myelotoxic antibiotic if feasible.
What other medicines interact with Clozapine?
MediHelp also lists interactions of Clozapine with, for example, Deferiprone, Irinotecan, Pimozide. The full list is on the Clozapine page.
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