Drug interactions
Methadone + Orphenadrin
Severity: Major
Methadone and Orphenadrin: 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
Orphenadrine can add to the sedative and respiratory depressant effects of methadone. Anticholinergic effects such as constipation and urinary retention may also be intensified. Impaired alertness and breathing problems are the main concerns, particularly when doses are started or raised.
What this interaction means in plain words
Methadone and Orphenadrin 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; Orphenadrin belongs to Musculoskeletal.
Why it happens
Additive central nervous system and respiratory depression, with added anticholinergic effects from orphenadrine.
What to do
Avoid the combination where possible, or use the lowest effective doses and monitor sedation and respiratory rate closely, especially at initiation and dose changes. Counsel the patient to avoid driving and alcohol.
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 Orphenadrin
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
Frequently asked questions
Can I take Methadone with Orphenadrin?
MediHelp rates the interaction as major. Methadone and Orphenadrin 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. Orphenadrine can add to the sedative and respiratory depressant effects of methadone. Anticholinergic effects such as constipation and urinary retention may also be intensified. Impaired alertness and breathing problems are the main concerns, particularly when doses are started or raised.
How serious is the interaction between Methadone and Orphenadrin?
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 the combination where possible, or use the lowest effective doses and monitor sedation and respiratory rate closely, especially at initiation and dose changes. Counsel the patient to avoid driving and alcohol.
What other medicines interact with Orphenadrin?
MediHelp also lists interactions of Orphenadrin with, for example, Alfentanil, Amobarbital, Benzhydrocodone / acetaminophen. The full list is on the Orphenadrin page.
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