Drug interactions
Fosaprepitant + Isoniazid
Severity: Minor
Fosaprepitant and Isoniazid: minor 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
Aprepitant, the active form of fosaprepitant, is a CYP3A4 substrate, but a single IV dose has limited exposure and isoniazid inhibition is weak. A meaningful interaction is unlikely.
What this interaction means in plain words
Fosaprepitant and Isoniazid have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Fosaprepitant belongs to Gastrointestinal Tract; Isoniazid belongs to Anti Bacterial.
Why it happens
Theoretical weak CYP3A4 inhibition by isoniazid reducing aprepitant metabolism.
What to do
No adjustment is required. Monitor for usual aprepitant adverse effects such as fatigue and hiccups.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Isoniazid
Other interactions of Fosaprepitant
- Flibanserin + Fosaprepitant Contraindicated
- Fosaprepitant + Pimozide Contraindicated
- Alprazolam + Fosaprepitant Moderate
- Amiodarone + Fosaprepitant Moderate
- Amobarbital + Fosaprepitant Moderate
- Apalutamide + Fosaprepitant Moderate
Frequently asked questions
Can I take Fosaprepitant with Isoniazid?
MediHelp rates the interaction as minor. Fosaprepitant and Isoniazid have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Aprepitant, the active form of fosaprepitant, is a CYP3A4 substrate, but a single IV dose has limited exposure and isoniazid inhibition is weak. A meaningful interaction is unlikely.
How serious is the interaction between Fosaprepitant and Isoniazid?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: No adjustment is required. Monitor for usual aprepitant adverse effects such as fatigue and hiccups.
What other medicines interact with Isoniazid?
MediHelp also lists interactions of Isoniazid with, for example, Bacillus calmette-guerin substrain tice, Benzhydrocodone / acetaminophen, Carbamazepine. The full list is on the Isoniazid page.
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