Drug interactions
Morphine + Orphenadrin
Severity: Major
Morphine 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 amplify the sedation and respiratory depression caused by morphine. Anticholinergic effects such as constipation, urinary retention and confusion may also worsen. The risk is greatest at therapy start and with dose increases.
What this interaction means in plain words
Morphine 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.
Morphine belongs to Musculoskeletal; Orphenadrin belongs to Musculoskeletal.
Why it happens
Additive central nervous system and respiratory depression, with added anticholinergic effects.
What to do
Avoid combining where possible; otherwise use the lowest effective doses and monitor sedation and respiratory rate. Counsel patients about avoiding alcohol and driving.
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 Morphine
- Alvimopan + Morphine Contraindicated
- Isocarboxazid + Morphine Contraindicated
- Morphine + Olanzapine / samidorphan Contraindicated
- Morphine + Phenelzine Contraindicated
- Morphine + Tranylcypromine Contraindicated
- Alfentanil + Morphine Major
Frequently asked questions
Can I take Morphine with Orphenadrin?
MediHelp rates the interaction as major. Morphine 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 amplify the sedation and respiratory depression caused by morphine. Anticholinergic effects such as constipation, urinary retention and confusion may also worsen. The risk is greatest at therapy start and with dose increases.
How serious is the interaction between Morphine 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 combining where possible; otherwise use the lowest effective doses and monitor sedation and respiratory rate. Counsel patients about avoiding alcohol and driving.
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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