Asa / Ascorbic Acid

What it is and how it works

Acetylsalicylic acid irreversibly inhibits cyclo-oxygenase (COX-1 and COX-2), reducing prostaglandin synthesis and producing analgesic, antipyretic and anti-inflammatory effects. Ascorbic acid (vitamin C) is added as an antioxidant, often in effervescent formulations.

Indications

Short-term relief of mild to moderate pain such as headache, toothache and muscular pain, and of fever and symptoms of colds and influenza in adults.

Dosage and administration (summary)

Oral, usually 400–1000 mg acetylsalicylic acid every 4–6 hours as required, dissolved in water, up to a maximum of 4 g daily in adults.

Contraindications

Children and adolescents under 16 years (risk of Reye's syndrome); active peptic ulcer or bleeding disorders; hypersensitivity to aspirin or NSAIDs (including aspirin-induced asthma); severe renal or hepatic impairment; third trimester of pregnancy.

Warnings and precautions

Risk of gastrointestinal bleeding, particularly in the elderly and with anticoagulants, corticosteroids or SSRIs. Use with caution in asthma, gout and G6PD deficiency. Effervescent forms contain sodium, relevant in salt-restricted diets.

Pregnancy

Avoid analgesic doses in pregnancy and contraindicated in the third trimester.

Storage and supply

Store below 25 °C in a dry place; keep the tube tightly closed to protect from moisture.

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