Drug interactions
Ifosfamide + Ritonavir
Severity: Moderate
Ifosfamide and Ritonavir: 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
Ritonavir strongly inhibits CYP3A4, which may reduce activation of ifosfamide and its efficacy, though it may also reduce neurotoxic metabolite formation. With long-term use ritonavir can also induce some enzymes, making the net effect uncertain.
What this interaction means in plain words
Ifosfamide and Ritonavir 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.
Ifosfamide belongs to Oncology; Ritonavir belongs to Anti Virals.
Why it happens
Strong CYP3A4 inhibition changes ifosfamide bioactivation, with possible additional enzyme induction effects.
What to do
Avoid combining when possible, or choose an antiretroviral without strong CYP3A4 inhibition. If combined, monitor for treatment response and toxicity.
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 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
Other interactions of Ritonavir
- Alfuzosin + Ritonavir Contraindicated
- Amiodarone + Ritonavir Contraindicated
- Avanafil + Ritonavir Contraindicated
- Colchicine + Ritonavir Contraindicated
- Dronedarone + Ritonavir Contraindicated
- Eletriptan + Ritonavir Contraindicated
Frequently asked questions
Can I take Ifosfamide with Ritonavir?
MediHelp rates the interaction as moderate. Ifosfamide and Ritonavir 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. Ritonavir strongly inhibits CYP3A4, which may reduce activation of ifosfamide and its efficacy, though it may also reduce neurotoxic metabolite formation. With long-term use ritonavir can also induce some enzymes, making the net effect uncertain.
How serious is the interaction between Ifosfamide and Ritonavir?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid combining when possible, or choose an antiretroviral without strong CYP3A4 inhibition. If combined, monitor for treatment response and toxicity.
What other medicines interact with Ifosfamide?
MediHelp also lists interactions of Ifosfamide with, for example, Adenovirus types 4 and 7 live, Measles mumps and rubella vaccine, Measles mumps and rubella vaccine live. The full list is on the Ifosfamide page.
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