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Can I take Gabapentin and Zapain together?

Drug interaction guide

Taking gabapentin and Zapain together can significantly increase the risk of severe drowsiness, dizziness, and breathing difficulties. Zapain contains codeine (an opioid) and paracetamol. When combined with gabapentin, the sedative effects of both drugs are multiplied. In serious cases, this can lead to shallow or slow breathing (respiratory depression), extreme sleepiness, or loss of consciousness.

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You must speak to your doctor before taking gabapentin and Zapain (co-codamol) together as they can significantly increase the risk of severe drowsiness, dizziness, and breathing difficulties.

If your doctor prescribes both, they will likely start you on the lowest possible doses and monitor you closely. Do not drive or operate machinery until you know how this combination affects you.

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Why this happens

Both gabapentin and the codeine in Zapain act as central nervous system (CNS) depressants. This means they both slow down brain activity and the signals that control breathing and alertness. When used together, they have an 'additive effect', meaning their combined impact is much stronger than taking either drug alone.

You may be experiencing an interaction between gabapentin and zapain if:

  • You feel excessively drowsy, sleepy, or sedated.

  • You experience dizziness, confusion, or difficulty concentrating.

  • You notice trouble with coordination or balance, increasing the risk of falls.

  • You develop constipation or difficulty passing urine.

  • You experience nausea or vomiting.

  • Symptoms appear shortly after taking both medicines together.

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If you have any of the above symptoms, you should:

  • Speak to your GP or pharmacist for advice on safe use and dosing.

  • Do not stop gabapentin or Zapain suddenly unless instructed by a healthcare professional.

  • Seek urgent medical help if you experience severe drowsiness, difficulty breathing, or persistent vomiting.

  • Avoid driving or operating machinery until you know how the combination affects you.

  • Tell your healthcare professional about all other medicines and supplements you are taking.

  • Avoid alcohol entirely, as it will make these dangerous side effects much worse.

Respiratory depression

Taking these medicines together significantly increases the risk of dangerous breathing difficulties. Seek immediate medical help if you experience slow, shallow breathing or extreme sleepiness.

Mental health disorders

A small number of people treated with gabapentin have had thoughts of harming or killing themselves. You must seek immediate medical help if you notice any changes in your mood or suicidal thoughts.

Abrupt discontinuation

Do not stop taking gabapentin suddenly. Doing so can cause serious side effects, including an increase in seizure frequency or severe withdrawal symptoms. Your dose must be reduced gradually.

Opioid addiction and withdrawal

Zapain contains codeine, which is addictive. Using it for more than 3 days can lead to physical dependence and withdrawal symptoms when you stop.

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Alcohol

It is best to avoid or strictly limit alcohol while taking these medicines. Combining alcohol with Zapain and Gabapentin significantly increases the risk of severe drowsiness, breathing difficulties, and coordination problems. Additionally, combining alcohol with paracetamol (in Zapain) increases the risk of liver damage.

Caffeine (Coffee, tea, energy drinks)

Zapain contains codeine, which can sometimes cause jitteriness or a fast heartbeat. High intake of caffeine may worsen these side effects or lead to increased anxiety and restlessness.

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.

  • 25 Jan 2026 | Originally published
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