Written by : Dr. Urusa I Inamdar

Introduction:

Paracetamol and acetaminophen are two official names of the same chemical compound derived from its chemical name : N-acetyl-para-aminophenol . It is an aniline derivative and the most extensively used over-the-counter and prescription analgesic worldwide . It has analgesic and anti-pyretic properties similar to non – steroidal antiinflammatory drugs (NSAIDS) but contrary to them , it does not possess any antiinflammatory properties .

Pharmacodynamics:

It acts mainly in the CNS by inhibiting cyclo oxygenase ( COX-2 ) . It acts by preventing the oxidation of inactive COX to active COX and thereby preventing prostaglandins synthesis through an active metabolite influencing cannabinoid receptors .

Pharmacokinetics:

It is rapidly absorbed from the gastrointestinal tract . The peak plasma concentrations are reached in about 2-3 hrs after rectal administration and reaches total serum concentrations of 5-20 micro g/ml . It is primarily metabolized in the liver by conjugation to gluconide and sulfate .

Indications:

• Analgesic
• Antipyretic

Contraindications:

• Alcoholism
• Hepatic disease
• Viral hepatitis
• Hypertension

Drug interactions:

Paracetamol interacts with enzyme inducing substances , such as isoniazid , carbamazepine , phenytoin or barbiturates , as well as chronic alcohol excess which increases N-acetyl-p-benzoquinone imine production and the risk of toxicity .

Adverse reactions:

• Allegic dermatitis
• Thrombocytopenia
• Agranulocytosis
• Hepatic necrosis

Dosage and administration:

As directed by the physician

Presentation:

Each suppository contains Paracetamol 125 mg

Reference:

• CIMS – prescribers handbook
• Kulkarni R et al. Indian J Pharmacol 2007
• Cullen S et al Arch Dis Child
• Roberts E et al. Ann Rheum Dis. 2016