Drug interactions
Nelfinavir + Rifaximin
Severity: Moderate
Nelfinavir and Rifaximin: 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
Nelfinavir inhibits P-glycoprotein and may raise systemic rifaximin exposure, which is normally very low. This is mainly of concern in patients with impaired liver function or severe gut mucosal disease where absorption is already increased.
What this interaction means in plain words
Nelfinavir and Rifaximin 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.
Nelfinavir belongs to Anti Virals; Rifaximin belongs to Anti Bacterial.
Why it happens
Inhibition of P-glycoprotein efflux of rifaximin increases its systemic absorption.
What to do
Use the combination only if benefit outweighs risk, particularly in hepatic impairment. Monitor for rifaximin adverse effects such as nausea, dizziness and headache.
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 Rifaximin
- Cholera vaccine + Rifaximin Major
- Microbiota + Rifaximin Major
- Amiodarone + Rifaximin Moderate
- Bcg intravesical live + Rifaximin Moderate
- Cyclosporine + Rifaximin Moderate
- Cyclosporin + Rifaximin Moderate
Other interactions of Nelfinavir
- Alfuzosin + Nelfinavir Contraindicated
- Avanafil + Nelfinavir Contraindicated
- Dronedarone + Nelfinavir Contraindicated
- Eletriptan + Nelfinavir Contraindicated
- Ergotamine + Nelfinavir Contraindicated
- Flibanserin + Nelfinavir Contraindicated
Frequently asked questions
Can I take Nelfinavir with Rifaximin?
MediHelp rates the interaction as moderate. Nelfinavir and Rifaximin 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. Nelfinavir inhibits P-glycoprotein and may raise systemic rifaximin exposure, which is normally very low. This is mainly of concern in patients with impaired liver function or severe gut mucosal disease where absorption is already increased.
How serious is the interaction between Nelfinavir and Rifaximin?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use the combination only if benefit outweighs risk, particularly in hepatic impairment. Monitor for rifaximin adverse effects such as nausea, dizziness and headache.
What other medicines interact with Rifaximin?
MediHelp also lists interactions of Rifaximin with, for example, Cholera vaccine, Microbiota, Amiodarone. The full list is on the Rifaximin page.
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