Codeine phosphate

Codeine phosphate is an opioid analgesic used to treat mild to moderate pain, as well as to relieve coughing and diarrhea. It is a phosphate salt of codeine, which is derived from morphine, an alkaloid found in the opium poppy.

Medical Uses

Codeine phosphate is commonly prescribed for:

• Pain management: It is effective in reducing mild to moderate pain.
• Cough suppression: It acts on the medulla oblongata to suppress the cough reflex.
• Diarrhea: It can be used to treat diarrhea due to its constipating effects.

Mechanism of Action

Codeine phosphate works by binding to opioid receptors in the central nervous system (CNS). This binding inhibits the release of neurotransmitters involved in the transmission of pain signals, thereby reducing the perception of pain. It also affects the medullary cough center to suppress coughing.

Pharmacokinetics

After oral administration, codeine phosphate is absorbed from the gastrointestinal tract. It undergoes hepatic metabolism, primarily through the enzyme CYP2D6, to form morphine, which is responsible for most of its analgesic effects. The drug is excreted primarily through the kidneys.

Side Effects

Common side effects of codeine phosphate include:

• Drowsiness
• Constipation
• Nausea and vomiting
• Dizziness
• Respiratory depression (in higher doses)

Contraindications

Codeine phosphate should not be used in individuals with:

• Respiratory depression
• Acute asthma
• Paralytic ileus
• Known hypersensitivity to codeine or other opioids

Interactions

Codeine phosphate can interact with other medications, including:

• CNS depressants: Increased risk of respiratory depression and sedation.
• MAO inhibitors: Risk of severe reactions.
• Anticholinergic drugs: Increased risk of constipation and urinary retention.

Regulation and Legal Status

Codeine phosphate is classified as a controlled substance in many countries due to its potential for abuse and dependence. It is available by prescription only.

See Also

• Opioid
• Morphine
• Pain management
• Cough suppressant
• Diarrhea treatment

Related Pages

• Opioid
• Morphine
• Pain management
• Cough suppressant
• Diarrhea treatment