Drug interactions
Efavirenz + Ifosfamide
Severity: Moderate
Efavirenz and Ifosfamide: 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 enzymes that activate ifosfamide, which may increase formation of both active alkylating metabolites and the neurotoxic and nephrotoxic metabolite chloroacetaldehyde. This could raise the risk of encephalopathy and kidney injury.
What this interaction means in plain words
Efavirenz and Ifosfamide 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 belongs to Anti Virals; Ifosfamide belongs to Oncology.
Why it happens
Induction of CYP3A4 and CYP2B6 increases ifosfamide bioactivation and toxic metabolite production.
What to do
Monitor for neurotoxicity, renal function and myelosuppression. Consider an alternative antiretroviral 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 Efavirenz
- Cobimetinib + Efavirenz Contraindicated
- Dienogest / estradiol valerate + Efavirenz Contraindicated
- Dihydroergotamine intranasal + Efavirenz Contraindicated
- Dihydroergotamine + Efavirenz Contraindicated
- Doravirine + Efavirenz Contraindicated
- Efavirenz + Elbasvir / grazoprevir Contraindicated
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 Efavirenz with Ifosfamide?
MediHelp rates the interaction as moderate. Efavirenz and Ifosfamide 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 enzymes that activate ifosfamide, which may increase formation of both active alkylating metabolites and the neurotoxic and nephrotoxic metabolite chloroacetaldehyde. This could raise the risk of encephalopathy and kidney injury.
How serious is the interaction between Efavirenz and Ifosfamide?
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 for neurotoxicity, renal function and myelosuppression. Consider an alternative antiretroviral if feasible.
What other medicines interact with Efavirenz?
MediHelp also lists interactions of Efavirenz with, for example, Cobimetinib, Dienogest / estradiol valerate, Dihydroergotamine intranasal. The full list is on the Efavirenz page.
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