Codeine is an opioid analgesic. Weaker opioid, such as codeine, is suitable for mild to moderate pain. This is much less potent than morphine and much less liable in normal doses. It produces adverse effects, including dependency. It is effective for mild to moderate pain but is too constipating for long-term use.
|Category of Drug||An Opioid Analgesics|
|Mechanism of Action||Codeine is a weak narcotic pain (1) reliever and cough suppressant. Its action is similar to morphine and hydrocodone—part of codeine converts to morphine in the body. Codeine binds to opioid receptors, which are responsible for transmitting the sensation of pain throughout the body and brain. Thus, codeine increases tolerance to pain.|
|Indications||1. Mild to moderate pain|
5. Irritable bowel syndrome.
|Codeine is mostly available in combination therapy.|
|Available dosage forms||1. TABLET|
|Dose|| 1. Adult- 30 to 60 mg every 4 h. (max. 240 mg/day)|
2. Children- 3 mg/kg daily in divided doses.
|1. The maximum plasma concentration- 60 minutes |
2. Vd- 3-6 L/kg
3. Protein binding- 7-25%
4. Metabolism- 70 to 80% in the liver (codeine-6 glucuronide)
5. Route of elimination- 90% by the kidneys.
6. Plasma half-life- 3 hours
|Molecular details||Molecular Formula- C18H21NO3|
Molecular Weight- 299.4 g/mol (2)
|Contraindications||1. Respiratory depression|
2. Obstructive airways disease
3. Acute asthma attack
4. Where the risk of paralytic ileus
6. Head injury
7. Increased intracranial pressure.
|Precautions||1. Hepatic impairment|
2. Opioids dependence
|Adverse Effects||1. Constipation|
5. Difficulty with micturition
6. Ureteric or biliary spasm
7. Orthostatic hypotension
8. Respiratory depression;