Codeine Phosphate


Note : Image for illustrative purposes only

Codeine Phosphate

Used for the treatment of Pain Relief

  • Increases tolerance to pain
  • Decreases discomfort
  • Effective treatment
From £49.99

What is Codeine?

Codeine, also known as Codeine Phosphate, is an opioid analgesic that works as a painkiller to provide relief for moderate to severe pain. It is often prescribed to people following operations or when they’ve sustained an injury, or for pain associated with sciatica, Paget’s disease or shingles. It can also be used for long-term pain where standard painkillers such as paracetamol or aspirin have failed to work. Codeine is related to morphine but has less potent analgesic properties and milder sedative effects. In addition to being prescribed for pain relief, it can also be used to treat diarrhoea and coughs. 

How does Codeine work?

When treating pain, codeine mimics the natural pain-reducing chemicals produced in the brain and spinal cord known as endorphins. The medication works on the same opioid receptors as the endorphins, blocking the transmission of pain signals that are sent along the nerves to the brain to reduce feelings of pain. The medication does not treat the cause of the pain, however.

When being taken to treat a cough, codeine works by reducing the nerve signals sent to a part of the brain that causes muscles to contract to produce coughing. Coughing is a reflex that occurs in response to irritation in the airways, typically to clear mucus or particles from the throat and lungs. When the patient is suffering with a cough, however, this reflex can become overstimulated even if there’s nothing in the throat to clear, which can lead to pain. Codeine can be taken to block this coughing reflex during such situations where coughing serves no purpose.

For the treatment of diarrhoea, codeine acts on opioid receptors which are found in the muscles of the intestinal walls. The codeine works to slow down the contractions of these muscles to reduce the speed at which the contents of the stomach are pushed through the intestines. This allows more time for electrolytes and water to be reabsorbed into the body to enable firmer stools and the need to pass stools less frequently, controlling the diarrhoea.

How to use Codeine

Codeine is administered orally in tablet form in patients over the age of 12. The exact dosage should be prescribed by your GP or pharmacist. Take Codeine with water, with or just after food so as to alleviate any nausea.


For moderate to severe pain

Adults should take the lowest effective dose up to 4 times a day at intervals no less than 6 hours, ensuring the daily dose does not exceed 240mg. The duration of treatment should be kept to three days, unless otherwise advised by a GP.

For children aged 12 to 18 years, the recommended dose is between 30 – 60mg every 6 hours, up to a maximum dose of 240mg per day. The dose should be based on the body weight of the patient, at 0.5-1mg per kg.


For dry or painful coughs

 In adults, the recommended dose is 15-30mg, 3 to 4 times a day. This dose should be reduced for elderly patients and is not recommended for children.



For adults, the recommended dose is 30mg, 3 to 4 times a day. This dose should be reduced for elderly patients and is not recommended for children.

If you forget to take a dose, take it as soon as you can. If it is almost time for your next dose, take that dose instead but never take two doses at the same time to make up for a forgotten one.


What are the side effects of Codeine?

Common side effects of Codeine include:

  • Constipation
  • Nausea or vomiting
  • Abdominal cramps
  • Tiredness and fatigue
  • Confusion, dizziness or vertigo
  • Dry mouth
  • Headache

Inform your GP or health care provider immediately if you experience any of the following side effects:

  • Difficulty breathing or shallow breathing
  • Muscle stiffness
  • Swelling of the mouth, lips, tongue or throat
  • Itchy, red, blistered or peeling skin
  • Symptoms of low blood pressure, including feeling tired or dizzy
  • Seizures

If you experience seizures (fit), go to A&E immediately.

If you experience prolonged side effects that do not subside over consistent use of the medication, or you are concerned about any side effects you are experiencing, contact your GP for advice.

Codeine should not be taken with alcohol as this can increase the likelihood of experiencing side effects, particularly tiredness and impact to breathing.

It may be an offence to drive while being treated with codeine, as the medication can cause sleepiness, drowsiness and the inability to concentrate. If you have blurred vision, don’t feel able to make decisions properly or experience any side effects related to drowsiness or tiredness, you should avoid driving until these side effects subside.

Before taking Codeine, inform your GP of your medical history. In particular, if you have experience of hypersensitivity to other opioid analgesics, kidney or liver disease, severe hepatic dysfunction, lung problems, seizures, head injuries, acute alcoholism, low blood pressure, symptoms of ulcerative colitis and respiratory problems, including asthma.

Codeine should not be taken post-operatively by children aged 12-18 years who have had surgery to remove their tonsils or adenoids for obstructive sleep apnoea, as this can be fatal.

You should also inform your GP or pharmacist of any medication you are currently taking, including anaesthetics, antidepressants, blood pressure medication, antihistamines, ulcer-healing medication, antiviral medication such as those for HIV or AIDS, hypnotics and any herbal remedies or supplements, as these can affect the efficiency of the drug and how your body reacts to the codeine.

Codeine should not be taken during pregnancy or while breastfeeding, as opioid analgesics may lead to gastric stasis during labour which can increase the risk of inhalation pneumonia in the mother. 

Can I buy Codeine online?

Codeine can be purchased online with a prescription from a registered doctor. You can use our online doctor service to request your prescription via a medical questionnaire which will be reviewed by a qualified GP and issued to you if you’re deemed suitable for the medication. This will usually be dispatched within 24 hours of ordering.

Patient Information Leaflet

Always read the patient information leaflet before commencing treatment. Patient information can be found

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