Drug interactions
Clozapine + Ifosfamide
Severity: Major
Clozapine and Ifosfamide: major interaction.
Last updated Sources: UK SmPC
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
Ifosfamide is myelosuppressive, and clozapine can cause severe neutropenia and agranulocytosis. Combined use may increase the risk and severity of bone marrow suppression and infection. Ifosfamide neurotoxicity may also be confused with or compounded by clozapine's CNS effects.
What this interaction means in plain words
Clozapine and Ifosfamide can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Clozapine belongs to Central Nervous System; Ifosfamide belongs to Oncology.
Why it happens
Additive bone marrow suppression.
What to do
Avoid concurrent use where possible, and otherwise monitor neutrophil counts closely. Involve the oncology and psychiatry teams to plan clozapine interruption if needed.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
- Clozapine Viatris 100 mg Orodispersible Tablets - SmPC sections 4.3/4.5 (class statement: cytotoxic agents; "Bone marrow suppressants (e.g. carbamazapine, chloramphenicol), sulphonamides (e.g. co-trimoxazole), pyrazolone analgesics (e.g. phenylbutazone), penicillamine,") — electronic medicines compendium (UK SmPC)
Other interactions of Clozapine
- Clozapine + Deferiprone Contraindicated
- Clozapine + Irinotecan Contraindicated
- Clozapine + Pimozide Contraindicated
- Clozapine + Thioridazine Contraindicated
- Acalabrutinib + Clozapine Major
- Adagrasib + Clozapine Major
Other interactions of Ifosfamide
- Adenovirus types 4 and 7 live + Ifosfamide Contraindicated
- Ifosfamide + Measles mumps and rubella vaccine Contraindicated
- Ifosfamide + Measles mumps and rubella vaccine live Contraindicated
- Ifosfamide + Measles mumps rubella and varicella vaccine live Contraindicated
- Ifosfamide + Measles vaccine Contraindicated
- Ifosfamide + Rotavirus oral vaccine live Contraindicated
Frequently asked questions
Can I take Clozapine with Ifosfamide?
MediHelp rates the interaction as major. Clozapine and Ifosfamide can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Ifosfamide is myelosuppressive, and clozapine can cause severe neutropenia and agranulocytosis. Combined use may increase the risk and severity of bone marrow suppression and infection. Ifosfamide neurotoxicity may also be confused with or compounded by clozapine's CNS effects.
How serious is the interaction between Clozapine and Ifosfamide?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid concurrent use where possible, and otherwise monitor neutrophil counts closely. Involve the oncology and psychiatry teams to plan clozapine interruption if needed.
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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