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Drug interactions

Diphenoxylate-atropine + Methadone

Severity: Major

Diphenoxylate-atropine and Methadone: 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

Both are opioids, so together they increase sedation and the risk of respiratory depression. Methadone has a long half-life, so effects can accumulate.

What this interaction means in plain words

Diphenoxylate-atropine and Methadone 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.

Diphenoxylate-atropine belongs to Gastrointestinal Tract; Methadone belongs to Musculoskeletal.

Evidence level: Moderate

Why it happens

Additive opioid CNS and respiratory depression.

What to do

Avoid unnecessary co-use; if needed, use the lowest effective doses and monitor sedation and breathing.

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?

Bring a full list of your medicines, including over-the-counter products, supplements and herbal remedies, to every pharmacy visit.

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References

Frequently asked questions

Can I take Diphenoxylate-atropine with Methadone?

MediHelp rates the interaction as major. Diphenoxylate-atropine and Methadone 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. Both are opioids, so together they increase sedation and the risk of respiratory depression. Methadone has a long half-life, so effects can accumulate.

How serious is the interaction between Diphenoxylate-atropine and Methadone?

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 unnecessary co-use; if needed, use the lowest effective doses and monitor sedation and breathing.

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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