Drug interactions
Dexfenfluramine + Morphine
Severity: Moderate
Dexfenfluramine 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
Dexfenfluramine increases serotonin release and blocks its reuptake, while morphine has weak serotonergic effects, so serotonin toxicity is theoretically possible. Clinical reports are scarce, and the sedative effects of the two drugs are not predictable.
What this interaction means in plain words
Dexfenfluramine 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.
Why it happens
Possible additive serotonergic activity; dexfenfluramine is a serotonin releasing agent and morphine has minor serotonergic effects.
What to do
Monitor for agitation, tremor, hyperreflexia, sweating and fever after starting or raising doses. Stop the serotonergic agent if serotonin syndrome is suspected.
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 Dexfenfluramine 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
Frequently asked questions
Can I take Dexfenfluramine with Morphine?
MediHelp rates the interaction as moderate. Dexfenfluramine 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. Dexfenfluramine increases serotonin release and blocks its reuptake, while morphine has weak serotonergic effects, so serotonin toxicity is theoretically possible. Clinical reports are scarce, and the sedative effects of the two drugs are not predictable.
How serious is the interaction between Dexfenfluramine 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 for agitation, tremor, hyperreflexia, sweating and fever after starting or raising doses. Stop the serotonergic agent if serotonin syndrome is suspected.
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.
