Drug interactions
Methadone + Pimavanserin
Severity: Major
Methadone and Pimavanserin: major interaction.
Last updated Sources: US FDA label
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
Both drugs have QT-prolonging potential, and pimavanserin is labeled with a warning on use with other QT-prolonging agents. Methadone also has serotonergic activity, though a clinically important serotonin syndrome is poorly documented.
What this interaction means in plain words
Methadone and Pimavanserin can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Methadone belongs to Musculoskeletal; Pimavanserin belongs to Central Nervous System.
Why it happens
Additive QT prolongation; a serotonergic contribution is theoretical.
What to do
Avoid if possible, or obtain a baseline ECG and monitor the QTc and electrolytes during co-therapy. Consider an alternative if QTc becomes prolonged.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
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 Pimavanserin
- Lefamulin + Pimavanserin Contraindicated
- Pimavanserin + Pimozide Contraindicated
- Pimavanserin + Vandetanib Contraindicated
- Adagrasib + Pimavanserin Major
- Amiodarone + Pimavanserin Major
- Amisulpride + Pimavanserin Major
Frequently asked questions
Can I take Methadone with Pimavanserin?
MediHelp rates the interaction as major. Methadone and Pimavanserin can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Both drugs have QT-prolonging potential, and pimavanserin is labeled with a warning on use with other QT-prolonging agents. Methadone also has serotonergic activity, though a clinically important serotonin syndrome is poorly documented.
How serious is the interaction between Methadone and Pimavanserin?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid if possible, or obtain a baseline ECG and monitor the QTc and electrolytes during co-therapy. Consider an alternative if QTc becomes prolonged.
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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