Drug interactions
Methadone + Nelfinavir
Severity: Moderate
Methadone and Nelfinavir: 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 CYP3A4 but also appears to induce other pathways, and its net effect is usually a modest decrease in methadone concentrations. Withdrawal symptoms have been reported in methadone patients taking it, though QT or sedation effects may occur if levels rise.
What this interaction means in plain words
Methadone and Nelfinavir 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.
Methadone belongs to Musculoskeletal; Nelfinavir belongs to Anti Virals.
Why it happens
Mixed CYP3A4 inhibition and induction of other methadone-metabolizing enzymes, with net change in methadone exposure that varies by patient.
What to do
Monitor for withdrawal and for signs of opioid excess after starting or stopping nelfinavir, and titrate methadone to clinical response.
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 Methadone
- Alvimopan + Methadone Contraindicated
- Calcium / magnesium / potassium / sodium oxybates + Methadone Contraindicated
- Droperidol + Methadone Contraindicated
- Ibutilide + Methadone Contraindicated
- Isocarboxazid + Methadone Contraindicated
- Lefamulin + Methadone Contraindicated
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 Methadone with Nelfinavir?
MediHelp rates the interaction as moderate. Methadone and Nelfinavir 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 CYP3A4 but also appears to induce other pathways, and its net effect is usually a modest decrease in methadone concentrations. Withdrawal symptoms have been reported in methadone patients taking it, though QT or sedation effects may occur if levels rise.
How serious is the interaction between Methadone and Nelfinavir?
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 withdrawal and for signs of opioid excess after starting or stopping nelfinavir, and titrate methadone to clinical response.
What other medicines interact with Methadone?
MediHelp also lists interactions of Methadone with, for example, Alvimopan, Calcium / magnesium / potassium / sodium oxybates, Droperidol. The full list is on the Methadone page.
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