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Can I take Codeine and Sertraline together?

Drug interaction guide

Taking codeine and sertraline together can make the codeine less effective at relieving pain. It may also increase the risk of a rare but serious condition called serotonin syndrome, and can lead to increased drowsiness or breathing difficulties.

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Why this happens

Sertraline can block the liver enzyme (CYP2D6) that the body needs to convert codeine into its active form, morphine. Without this conversion, the codeine cannot work properly to stop pain. Additionally, both drugs affect brain chemicals (serotonin and CNS depression), which can lead to additive side effects.

Speak to your doctor before taking these together. If you are already taking them and find your pain is not being controlled, or if you feel unusually sleepy, dizzy, or develop a fever and tremors, seek medical advice. Your doctor may suggest an alternative painkiller that does not rely on this specific liver enzyme.

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Taking multiple medicines? Our Medicines Interaction Checker helps you check whether your prescriptions, over-the-counter medicines, and supplements are safe to take together. Simply search for your medicines to see potential interactions and what to do about them.

Disclaimer

This information is for general educational purposes only and should not be relied upon as a substitute for professional medical advice. Always consult your GP, pharmacist, or another qualified healthcare professional before making decisions about your medications. Individual circumstances may vary, and only a healthcare professional who knows your medical history can provide personalised guidance.

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Article history

The information on this page is written and peer reviewed by qualified clinicians.

  • 14 Mar 2026 | Originally published
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