Asa / Codeine Phosphate

What it is and how it works

Aspirin inhibits cyclo-oxygenase, reducing prostaglandin-mediated pain and inflammation; codeine is a weak opioid agonist whose analgesic action depends mainly on CYP2D6-mediated conversion to morphine. The combination provides additive analgesia.

Indications

Short-term relief of acute moderate pain not relieved by simple analgesics alone.

Dosage and administration (summary)

Oral, usually 1–2 tablets every 4–6 hours as required, within maximum daily limits for aspirin and codeine (240 mg); treatment should be limited to about 3 days.

Contraindications

Children and adolescents under 16 years (aspirin) and under 12 years (codeine); CYP2D6 ultra-rapid metabolisers; breastfeeding; active peptic ulcer or bleeding disorders; aspirin or NSAID hypersensitivity; acute respiratory depression; third trimester of pregnancy.

Warnings and precautions

Risk of gastrointestinal bleeding, respiratory depression, dependence and medication-overuse headache. Caution with anticoagulants, CNS depressants and alcohol, and in asthma, renal or hepatic impairment. Causes constipation and drowsiness.

Pregnancy

Avoid in pregnancy; contraindicated in the third trimester.

Storage and supply

Store below 25 °C, protected from moisture.

Source: reference summary prepared from the EU SmPC/EPAR, BNF and WHO Model Formulary. The approved product information in Iran governs.