Drug interactions
Diphenoxylate + Morphine
Severity: Moderate
Diphenoxylate and Morphine: moderate 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
Diphenoxylate is an opioid antidiarrheal, and with morphine it can add to sedation and respiratory depression at higher doses. Constipation and ileus risk are also increased.
What this interaction means in plain words
Diphenoxylate and Morphine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Diphenoxylate belongs to Gastrointestinal Tract; Morphine belongs to Musculoskeletal.
Why it happens
Additive mu-opioid receptor agonism affecting CNS, respiration and gut motility.
What to do
Monitor sedation, respiratory rate and bowel function, and keep diphenoxylate within labelled doses. Reassess the need for antidiarrheal therapy in patients on opioids.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Diphenoxylate and Morphine, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
Other interactions of Morphine
- Alvimopan + Morphine Contraindicated
- Isocarboxazid + Morphine Contraindicated
- Morphine + Olanzapine / samidorphan Contraindicated
- Morphine + Phenelzine Contraindicated
- Morphine + Tranylcypromine Contraindicated
- Alfentanil + Morphine Major
Other interactions of Diphenoxylate
Frequently asked questions
Can I take Diphenoxylate with Morphine?
MediHelp rates the interaction as moderate. Diphenoxylate and Morphine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Diphenoxylate is an opioid antidiarrheal, and with morphine it can add to sedation and respiratory depression at higher doses. Constipation and ileus risk are also increased.
How serious is the interaction between Diphenoxylate and Morphine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor sedation, respiratory rate and bowel function, and keep diphenoxylate within labelled doses. Reassess the need for antidiarrheal therapy in patients on opioids.
What other medicines interact with Morphine?
MediHelp also lists interactions of Morphine with, for example, Alvimopan, Isocarboxazid, Olanzapine / samidorphan. The full list is on the Morphine page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
