Can I take Codeine and Morphine together?
Drug interaction guide
Originally published 24 Jan 2026
Meets Patient’s editorial guidelines
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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
Back to contentsYou 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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Important precautions
Back to contentsBreathing problems (e.g. COPD, severe asthma)
These medicines can dangerously slow your breathing. Do not take them if you have severe lung disease or are having an asthma attack.
Alcohol consumption
Drinking alcohol while taking these medicines significantly increases the risk of life-threatening breathing difficulties and extreme sleepiness.
Addiction and Dependency
Codeine contains an opioid which can cause addiction if used for more than 3 days. Long-term use can lead to withdrawal symptoms when you stop.
Breastfeeding
Do not take codeine while breastfeeding. It passes into breast milk and can cause life-threatening breathing problems or extreme sleepiness in your baby.
Food and drink warnings
Back to contentsAlcohol
It is best to avoid or strictly limit alcohol while taking these medicines. Combining alcohol with strong painkillers like codeine or morphine significantly increases the risk of dangerous side effects, such as extreme sleepiness, breathing difficulties, and a potentially fatal overdose.
Grapefruit juice
Grapefruit juice can interfere with how your body processes codeine. This may make the medicine less effective at relieving pain or, in some cases, increase the risk of side effects. It is best to avoid drinking large amounts of grapefruit juice while taking codeine.
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Using other medicines
Back to contentsTaking 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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