Codeine Phosphate

Codeine is an opioid analgesic. It is much less potent as an analgesic than morphine and has relatively mild sedative effects. Codeine or its salts, especially the phosphate, are given orally in the form of linctus for the relief of cough, and as tablets for the relief of mild to moderate pain, often with a non-opioid analgesic such as paracetamol.

Pronunciation

Codeine phosphate 30mg

Generic Name 藥名	HA Code 藥物代碼	Classification藥物分類
Codeine phosphate 30 mg tablet	COED01	DD

Mechanism of Action

Equivalent doses of opioid analgesics

Analgesic/Route	Dose
Codeine: PO	100 mg
Diamorphine: IM, IV, SC	3 mg
Dihydrocodeine: PO	100 mg
Morphine: PO	10 mg
Morphine: IM, IV, SC	5 mg
Oxycodone: PO	6.6 mg
Tramadol: PO	100 mg

Route of Adminstration

IV

PO (tablet form)

PO (suspension)

Dosage

Mild to moderate pain:

Oral: 30-60 mg every 4 hours, max 240 mg/day.

For non-productive cough:

Oral: 15 to 50mg three or four times daily.

Doses in children

The use of codeine is restricted to the short-term treatment of acute, moderate pain in children over 12 years of age who do not respond to other analgesics such as paracetamol or ibuprofen.

The recommended oral dose:

• 30 to 60 mg (0.5 to 1 mg/kg) of codeine phosphate given every 6 hours when necessary, max of 240 mg daily.
• The duration of treatment should not exceed 3 days.

Side Effects

As for Opioid Analgesic in general

The commonest adverse effects are nausea, vomiting, constipation, drowsiness and confusion.

Large doses of opioids produce respiratory depression and hypotension, with circulatory failure and deepening coma. Death may occur from respiratory failure.

Treatment of Adverse Effects

1. Constipation can be treated with laxatives such as senna tables and lactulose. 2. Nausea and vomiting can be alleviated by metoclopramide. 3. Intensive supportive therapy may be required to correct respiratory failure and shock. Naloxone is used for rapid reversal of the severe respiratory depression and coma.

Euphoria, nausea and vomiting, respiratory depression, constipation and cough suppression

Pharmacokinetics

Oral bioavailability	Codeine and its salts are absorbed from the gastrointestinal tract.
Onset of action
Excreation	Codeine and its metabolites are excreted almost entirely by the kidney.
Elimination half-life	The plasma half-life has been reported to be between 3 and 4 hours after an oral or intramuscular dose.