What is Codeine Phosphate

Codeine Phosphate

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Codeine phosphate for pain relief

Codeine phosphate is a prescription drug used to treat the signs and symptoms of mild to moderately severe pain. It belongs to a class of opioids and analgesic, antitussive, and antidiarrheal medication. Codeine phosphate is a pain relief medication produced from morphine or opium and interacts with opioid receptors in the central nervous system. It also works to block your emotional response to pain.

When codeine phosphate is used in combination with other drugs it can make you feel drowsy and cause decreased awareness and breathing problems.

Its safety and effectiveness in young patients are unknown so there may be an increased risk of side effects. It should not be given to anyone under 12 years of age or to adolescents (aged less than 18 years) following surgery to remove tonsils or adenoids, or for those whose respiratory function might be compromised.

It is often prescribed to relieve mild to moderate pain relief from pain associated with a terminal illness, post-operative pain, headaches and coughs. It can also be used to provide symptomatic relief from diarrhoea, except diarrhoea caused by poisoning.

Side Effects of Codeine Phosphate

Side effects of Codeine Phosphate

Serious adverse effects of codeine phosphate include:

  • Agitated breathing

  • Nausea

  • Sighing

  • Slow breathing

  • Apnea

  • Sluggish beating heart

  • Confusion

  • Weak pulse

  • Light-headedness

  • Feeling drowsy or dizzy

  • Abdominal cramps

  • The strong emotion of pleasure and despair

  • Unusual feelings or actions

  • Loss of appetite

  • Convulsions

  • Urinary disorders

  • Unsteadiness

  • Deteriorating fatigue or sluggishness

Immediately seek medical help if you experience any of the symptoms mentioned above.

Drug Interactions

Codeine phosphate may cause drug dependence and can thus be misused, although being far less potent than morphine. Patients who receive 60 mg of codeine phosphate every six hours for two months often develop a tolerance to the drug and have minor withdrawal symptoms. It is therefore important to never take more than your maximum daily dose.

Increased analgesic effect tolerance and the emergence of purposeful occurrences (complaints, requests, demands, or manipulative behaviours) just before the next dosage is two signs that the dependent state is developing. A patient who is withdrawing has to be handled in a hospital setting. Typically, just supportive care is required, along with the injection of a tranquillizer to reduce anxiety.

Furthermore, if withdrawal symptoms are severe, it can be necessary to provide a substitute narcotic. Codeine phosphate has additive depressing effects when combined with other narcotic analgesics, phenothiazines, general anaesthetics, tranquillizers, sedative-hypnotics, or other CNS depressants (such as alcohol). The dose of one or both medicines should be decreased when s.c. combination treatment is being considered. You must not drink alcohol while using codeine phosphate tablets.

Taking Codeine Phosphate While Pregnant or Nursing

Taking Codeine Phosphate when pregnant or nursing

A pregnant woman must discuss the risks and advantages of taking this medicine with healthcare professionals. Inform them if you are expecting a child or have plans to do so since this drug should only be used during pregnancy if necessary. Also, taking the first two months of pregnancy may raise the chance of birth abnormalities.

Additionally, taking it often or in a high dose close to the anticipated birth date may harm the unborn child. Hence, use the lowest effective dosage for the shortest time to reduce danger. Also, codeine phosphate is excreted in breast milk, and a breastfeeding newborn may sometimes have unfavourable effects. If you see any signs in your newborn infant, such as slow or shallow breathing, irritability, unusual or continuous crying, vomiting, or diarrhoea, call for medical help immediately.

Moreover, call healthcare professionals immediately if your baby begins to exhibit other symptoms like unusual limpness, difficulty breathing, difficulty breastfeeding, or increasing drowsiness. Before you breastfeed, talk with your doctor about the advantages and disadvantages.

Warnings and Precautions

  • Increased Intracranial Pressure and Head Injury

When there is a head injury, other cerebral lesions, or an increase in intracranial pressure, the effects of opioids on breathing and their ability to raise cerebrospinal fluid pressure may be noticeably exacerbated. Narcotics can have adverse side effects that might muddle the therapeutic course in individuals with brain trauma.

  • Liver or Kidney Disease

In individuals with liver or renal failure, the cumulative effects of codeine phosphate may last for a long time.

  • Acute Abdominal Disorders

Introducing codeine or other opioids may obfuscate the diagnosis or clinical course in individuals with acute gastrointestinal problems.

  • Patients at Particular Risk

Certain individuals, such as the elderly or disabled, those with severe hepatic or renal function, hypothyroidism, prostatic hypertrophy, Addison's disease, or those with urethral stricture, should be administered codeine with care.

Codeine Phosphate Dosage

In addition to containing as many mixed analgesic solutions, codeine phosphate's usual dose comes in 30 mg and 60 mg tablets for oral use. The typical adult dose is 30 mg, while the dosage for children one year of age and older is weight-based (0.5 mg/Kg) every 4 to 6 hours. The typical adult dose is 15 to 60 mg every 4 to 6 hours.


The effects of codeine phosphate, converted to morphine in the body, are comparable to those of morphine and other opioid analgesics. Miosis, sedation, and respiratory depression are typical overdose symptoms. Other signs and symptoms include chilly, clammy skin, bradycardia, hypotension, skeletal muscle flaccidity, nausea, and vomiting. Furthermore, children have had apnoea with dosages as little as 5 mg/kg, and death may result. Monitoring of heart filling pressure may be beneficial since noncardiac pulmonary oedema caused by opioid overdose may occur.

It is important to thoroughly discuss this medication with your physician as codeine-containing medicines can lead to drug dependence and exacerbate your conditions if you have a certain mental health disorder. You may be at increased risk of life-threatening adverse reactions especially if you are older or have an existing problem with your lungs. This is known as life-threatening respiratory depression and can cause fatal breathing problems even when used at the correct dose. Health professionals only prescribe this medication when other treatment options cannot effectively manage to provide adequate pain relief. Taking codeine phosphate poses a risk of abuse, misuse and addiction which could lead to overdose and death.

To learn more about pain relief or to see our range of pain relief medications, see our information page here.

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