Drug interactions
Lopinavir + Methadone
Severity: Moderate
Lopinavir and Methadone: 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
Lopinavir/ritonavir has mixed effects on methadone, with ritonavir inducing some pathways and inhibiting others, and methadone levels often fall. Lopinavir also prolongs the QT interval, adding cardiac risk. Clinical effects can be unpredictable, ranging from withdrawal to toxicity.
What this interaction means in plain words
Lopinavir and Methadone 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.
Lopinavir belongs to Anti Virals; Methadone belongs to Musculoskeletal.
Why it happens
Combined CYP3A4 inhibition and induction of other metabolic pathways by lopinavir/ritonavir alters methadone clearance, with additive QT effects.
What to do
Monitor for opioid withdrawal or toxicity when starting or stopping lopinavir and adjust the methadone dose to clinical response. Obtain an ECG if other QT risk factors exist.
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 Lopinavir
- Alfuzosin + Lopinavir Contraindicated
- Avanafil + Lopinavir Contraindicated
- Cisapride + Lopinavir Contraindicated
- Dronedarone + Lopinavir Contraindicated
- Eletriptan + Lopinavir Contraindicated
- Eplerenone + Lopinavir Contraindicated
Frequently asked questions
Can I take Lopinavir with Methadone?
MediHelp rates the interaction as moderate. Lopinavir and Methadone 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. Lopinavir/ritonavir has mixed effects on methadone, with ritonavir inducing some pathways and inhibiting others, and methadone levels often fall. Lopinavir also prolongs the QT interval, adding cardiac risk. Clinical effects can be unpredictable, ranging from withdrawal to toxicity.
How serious is the interaction between Lopinavir and Methadone?
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 opioid withdrawal or toxicity when starting or stopping lopinavir and adjust the methadone dose to clinical response. Obtain an ECG if other QT risk factors exist.
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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