Codeine

Codeine is an opium alkaloid qualitatively similar to and less potent than morphine. It is regarded as the standard antitussive drug, suppressing cough for about 6 hours. The aim is to control rather than eliminate cough; hence should be used only for dry, nonproductive cough or if the cough is unduly tiring, disturbs sleep, or is hazardous, i.e.: hernia, piles, or cardiac disease.

Mechanism of action.

• In the CNS, the drug raises the threshold of the cough center.
• It acts peripherally in the respiratory tract to reduce tussal impulses.

Clinical uses.

• Management of cough.
• Pain management.

Adverse effects.

• Constipation and drowsiness.
• Hypotension, tachycardia, and confusion
• Headache, Lightheadedness
• Malaise.

Drug interaction.

• Fentanyl increases the effects of codeine by pharmacodynamic synergism.
• Codeine increases the toxicity of rasagiline.
• Cimetidine increases the level and effect of codeine by affecting hepatic enzyme CYP2D6 metabolism.

Contraindication.

· Hypersensitivity to codeine.

· Significant respiratory depression.

· Children younger than 12 years.

· Acute or severe bronchial asthma.

· Gastrointestinal obstruction, including paralytic ileus.

• In asthmatics.
• Patients with diminished respiratory reserve.

Dosage.

• Dose: 10–30 mg; children 2–6 years 2.5–5 mg, 6–12 years.
• 5–10 mg, frequently used as syrup.
• CODEINE 15 mg tablets, 15 mg/5 ml linctus.