Can I take Diazepam and Codeine together?

Why this happens

Both medicines are 'central nervous system depressants'. This means they both slow down brain activity and the signals that tell your body to breathe. When taken together, their effects add up, making the impact on your breathing and alertness much stronger than if taken alone.

You should only take these two medicines together if they have been specifically prescribed by the same doctor who is aware you are taking both. If you must take both, use the lowest dose possible for the shortest amount of time. Seek emergency medical help immediately if you experience extreme sleepiness, shallow breathing, or difficulty staying awake. Avoid alcohol completely while taking these medicines.

Combined use with other sedatives or alcohol

Taking these medicines together, or with alcohol, significantly increases the risk of life-threatening breathing problems and extreme sleepiness. Avoid alcohol and do not take other sedating medicines unless specifically directed by your doctor.

Ultra-rapid metabolism (CYP2D6)

Some people turn codeine into morphine much faster than normal. If you experience extreme sleepiness, confusion, or shallow breathing, stop taking the medicine and seek urgent medical help. This is especially dangerous for breastfeeding mothers as it can cause fatal overdose in the baby.

Long-term use and dependence

These medicines are for short-term use only. Taking them for more than a few days can lead to physical addiction and withdrawal symptoms when you stop. Do not increase the dose or take them for longer than prescribed.

Asthma or breathing problems

Do not take codeine if you have severe asthma or breathing difficulties, as it can dangerously slow down your breathing.

Driving and operating machinery

It is often an offence to drive while taking diazepam as it can seriously impair your coordination and reaction times. Do not drive or operate machinery until you know how this medicine affects you, and always keep the medicine in its original packaging to show the police if stopped.

Respiratory depression

Do not take diazepam if you have severe lung disease or breathing difficulties, as it can further slow your breathing to dangerous levels.

Pregnancy

Avoid use in late pregnancy or during labour, as it can cause 'floppy infant syndrome' and life-threatening withdrawal symptoms in the newborn.

Alcohol

You must avoid drinking alcohol while taking these medicines. Both diazepam and codeine cause drowsiness and slow down your breathing. Alcohol significantly increases these effects, which can lead to dangerous levels of sedation, breathing difficulties, and loss of consciousness.

Grapefruit juice

Avoid drinking large amounts of grapefruit juice. Grapefruit contains compounds that can stop your body from breaking down diazepam properly. This can lead to higher levels of the medicine in your blood, increasing the risk of side effects like extreme sleepiness and poor coordination.

Caffeine (Coffee, tea, energy drinks)

Caffeine is a stimulant and can have the opposite effect of diazepam, which is a sedative. Consuming high amounts of caffeine may make diazepam less effective at treating anxiety or helping you sleep.

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.