Drug interactions
Codeine + Venlafaxine
Severity: Minor
Codeine and Venlafaxine: minor 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
Venlafaxine is a weak CYP2D6 inhibitor and may slightly reduce activation of codeine to morphine, though the effect is usually small. Both drugs have serotonergic properties, so serotonin toxicity is possible but uncommon.
What this interaction means in plain words
Codeine and Venlafaxine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Codeine belongs to Musculoskeletal; Venlafaxine belongs to Central Nervous System.
Why it happens
Weak CYP2D6 inhibition by venlafaxine, plus additive serotonergic activity.
What to do
Monitor analgesic response and watch for signs of serotonin toxicity such as agitation, tremor and hyperthermia. No routine dose change is needed.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Codeine
- Alvimopan + Codeine Contraindicated
- Codeine + Isocarboxazid Contraindicated
- Codeine + Olanzapine / samidorphan Contraindicated
- Codeine + Phenelzine Contraindicated
- Codeine + Tranylcypromine Contraindicated
- Alfentanil + Codeine Major
Other interactions of Venlafaxine
- Isocarboxazid + Venlafaxine Contraindicated
- Methylene blue + Venlafaxine Contraindicated
- Phenelzine + Venlafaxine Contraindicated
- Procarbazine + Venlafaxine Contraindicated
- Rasagiline + Venlafaxine Contraindicated
- Safinamide + Venlafaxine Contraindicated
Frequently asked questions
Can I take Codeine with Venlafaxine?
MediHelp rates the interaction as minor. Codeine and Venlafaxine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Venlafaxine is a weak CYP2D6 inhibitor and may slightly reduce activation of codeine to morphine, though the effect is usually small. Both drugs have serotonergic properties, so serotonin toxicity is possible but uncommon.
How serious is the interaction between Codeine and Venlafaxine?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor analgesic response and watch for signs of serotonin toxicity such as agitation, tremor and hyperthermia. No routine dose change is needed.
What other medicines interact with Codeine?
MediHelp also lists interactions of Codeine with, for example, Alvimopan, Isocarboxazid, Olanzapine / samidorphan. The full list is on the Codeine page.
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