Drug interactions
Clozapine + Orphenadrin
Severity: Major
Clozapine 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
Clozapine is highly sedating and strongly anticholinergic, and orphenadrine adds to both effects. This can increase drowsiness, constipation (with risk of severe hypomotility), urinary retention and confusion.
What this interaction means in plain words
Clozapine 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.
Clozapine belongs to Central Nervous System; Orphenadrin belongs to Musculoskeletal.
Why it happens
Additive central sedation and muscarinic blockade, which compounds clozapine-related gastrointestinal hypomotility.
What to do
Avoid the combination where possible, or monitor closely for oversedation and constipation and treat bowel symptoms early. Consider a non-anticholinergic alternative for muscle spasm.
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 Clozapine
- Clozapine + Deferiprone Contraindicated
- Clozapine + Irinotecan Contraindicated
- Clozapine + Pimozide Contraindicated
- Clozapine + Thioridazine Contraindicated
- Acalabrutinib + Clozapine Major
- Adagrasib + Clozapine Major
Frequently asked questions
Can I take Clozapine with Orphenadrin?
MediHelp rates the interaction as major. Clozapine 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. Clozapine is highly sedating and strongly anticholinergic, and orphenadrine adds to both effects. This can increase drowsiness, constipation (with risk of severe hypomotility), urinary retention and confusion.
How serious is the interaction between Clozapine 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 monitor closely for oversedation and constipation and treat bowel symptoms early. Consider a non-anticholinergic alternative for muscle spasm.
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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