Drug interactions
Diphenoxylate-atropine + Phenobarbital
Severity: Major
Diphenoxylate-atropine and Phenobarbital: major interaction.
Last updated
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
Phenobarbital and diphenoxylate both depress the central nervous system, so combined use increases sedation and the risk of respiratory depression. Phenobarbital is also a CYP inducer, though the main concern here is additive sedation.
What this interaction means in plain words
Diphenoxylate-atropine and Phenobarbital 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 depression via GABA-A enhancement by barbiturates and opioid receptor agonism.
What to do
Avoid combining where possible; if necessary use the lowest doses and monitor sedation and respiratory rate. Advise against 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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Other interactions of Diphenoxylate-atropine
- Diphenoxylate-atropine + Isocarboxazid Contraindicated
- Diphenoxylate-atropine + Phenelzine Contraindicated
- Diphenoxylate-atropine + Tranylcypromine Contraindicated
- Alfentanil + Diphenoxylate-atropine Major
- Alvimopan + Diphenoxylate-atropine Major
- Amitriptyline + Diphenoxylate-atropine Major
Frequently asked questions
Can I take Diphenoxylate-atropine with Phenobarbital?
MediHelp rates the interaction as major. Diphenoxylate-atropine and Phenobarbital 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. Phenobarbital and diphenoxylate both depress the central nervous system, so combined use increases sedation and the risk of respiratory depression. Phenobarbital is also a CYP inducer, though the main concern here is additive sedation.
How serious is the interaction between Diphenoxylate-atropine and Phenobarbital?
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; if necessary use the lowest doses and monitor sedation and respiratory rate. Advise against alcohol and driving.
What other medicines interact with Diphenoxylate-atropine?
MediHelp also lists interactions of Diphenoxylate-atropine with, for example, Isocarboxazid, Phenelzine, Tranylcypromine. The full list is on the Diphenoxylate-atropine page.
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