Drug interactions
Diamorphine + Orphenadrin
Severity: Major
Diamorphine and Orphenadrin: major interaction.
Last updated Sources: Health Canada product monograph
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
Diamorphine is a potent opioid and orphenadrine adds sedation and anticholinergic effects. Together they may cause deep sedation, respiratory depression, constipation and urinary retention.
What this interaction means in plain words
Diamorphine 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.
Why it happens
Additive CNS and respiratory depression, plus additive antimuscarinic effects.
What to do
Use the lowest effective doses and monitor respiratory rate and sedation closely. Avoid in patients with respiratory compromise.
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
Frequently asked questions
Can I take Diamorphine with Orphenadrin?
MediHelp rates the interaction as major. Diamorphine 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. Diamorphine is a potent opioid and orphenadrine adds sedation and anticholinergic effects. Together they may cause deep sedation, respiratory depression, constipation and urinary retention.
How serious is the interaction between Diamorphine 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: Use the lowest effective doses and monitor respiratory rate and sedation closely. Avoid in patients with respiratory compromise.
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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