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Can I take Codeine and Morphine together?

Drug interaction guide

Taking codeine and morphine together significantly increases the risk of serious side effects, including extreme sleepiness, dizziness, and dangerous breathing problems. Because both drugs are strong painkillers from the same family (opioids), they 'stack' on top of each other, which can lead to an accidental overdose.

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Why this happens

Both codeine and morphine work by attaching to the same receptors in the brain and spinal cord to block pain. Additionally, the body naturally converts a portion of codeine into morphine after you swallow it. Taking both means you are essentially taking a double dose of morphine, which can overwhelm the central nervous system.

What you should do

You should not take codeine and morphine together unless specifically instructed and closely monitored by a specialist. If you have been prescribed both, speak to your doctor or pharmacist immediately to clarify the dosing schedule. Seek emergency medical help if you experience extreme drowsiness, confusion, shallow breathing, or difficulty waking up.

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Using other medicines

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.

  • 24 Jan 2026 | Originally published
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