Skip to content

Opioid analgesic; also used as a cough suppressant; controlled medicine

Codeine: uses, side effects & precautions

Also known as Codeine phosphate, Co-codamol (with paracetamol), Tylenol with Codeine.

Esta información es solo orientativa de carácter general y no constituye un consejo médico. Consulta siempre a un profesional sanitario cualificado para cualquier asunto médico personal. En caso de emergencia, llama al número de emergencias de tu zona.

What it is used for

  • Mild to moderate pain, often combined with paracetamol or ibuprofen
  • Pain not relieved by non-opioid painkillers alone
  • Dry cough (in some products)
  • Short-term relief of acute diarrhoea in some regions

How it works

Codeine is converted in the body to morphine, which acts on opioid receptors in the brain and spinal cord to reduce the sensation of pain. It also suppresses the cough reflex.

How it is taken

Available as tablets and oral liquid, and commonly in combination products with paracetamol or ibuprofen, and in some cough medicines. It is a controlled medicine and must be taken exactly as prescribed or labelled, for the shortest time needed. Check combination products to avoid doubling up on paracetamol or ibuprofen.

No doses here on purpose. The right strength and schedule depend on you — only a doctor or pharmacist should set them. Always follow your prescription and the label.

Common side effects

  • Constipation
  • Nausea or vomiting
  • Drowsiness or dizziness
  • Dry mouth

Serious effects — get help

  • Slow or shallow breathing (a medical emergency, particularly in overdose or with alcohol/sedatives)
  • Serious allergic reaction
  • Signs of dependence or withdrawal
  • Severe drowsiness or confusion
  • In children and some adults who process codeine rapidly, dangerous opioid effects can occur

If a reaction is severe — for example trouble breathing, swelling of the face or throat, or collapse — go to the nearest emergency room now or call your local emergency number. Do not wait for an online consultation.

Interactions to watch

  • Alcohol and other sedatives (dangerous breathing depression)
  • Other opioids and medicines containing paracetamol or ibuprofen (overdose risk)
  • Some antidepressants and medicines affecting codeine's processing
  • Medicines that cause constipation or drowsiness

Who should take care

  • Not recommended for children, and avoided after tonsil or adenoid surgery in children, due to serious breathing risks
  • Avoided in breastfeeding because it can pass to the baby; use in pregnancy only if a doctor advises
  • Can cause dependence — use for the shortest time, do not exceed the directed amount, and do not share it
  • Avoid alcohol; tell your doctor about breathing, liver or kidney problems and all other medicines
  • Seek urgent care for slow breathing or severe drowsiness

Frequently asked questions

Why isn't codeine recommended for children?
Some children convert codeine to morphine very quickly, which can dangerously slow breathing. It is generally avoided in children and is unsafe after certain throat surgeries.
Can codeine become habit-forming?
Yes, as an opioid it can cause dependence with regular use. Use it only as directed and for as short a time as possible.
Why does it cause constipation?
Opioids slow the gut, which commonly causes constipation. Drinking fluids, eating fibre, and asking your pharmacist about remedies can help.
Can I take co-codamol and paracetamol together?
No, co-codamol already contains paracetamol, so adding more risks an overdose. Always check what is in your combination product.
Is Codeine safe to take?
For most people it is safe when taken exactly as a doctor or pharmacist advises and as printed on the label. Tell your clinician about your other medicines and health conditions, and seek urgent care for any serious reaction.

Related medicines

See a doctor online now