Tylenol Mechanism of Action





Full Prescribing Info
Analgesic and antipyretic.
Pharmacokinetics: Paracetamol is rapidly absorbed from the gastrointestinal tract, primarily in the small intestine. This absorption process occurs by passive transport. Paracetamol is metabolized primarily by 1st-order kinetics. Mean maximal plasma levels occur within 20-90 min following ingestion. Paracetamol is metabolized in the liver.
In adults, the majority of paracetamol is conjugated with glucuronic acid and to a lesser extent with sulfuric acid. These conjugated metabolites lack biological activity. In premature, newborn and young infants, the sulfate conjugate predominates. Paracetamol appears to be widely distributed throughout most body fluids except fat and cerebrospinal fluid. Paracetamol binds minimally (<10%) to plasma proteins and binding is only increased slightly in plasma concentrations associated with overdose. The sulfate and glucuronide conjugates do not bind to plasma proteins even at relatively high concentrations.
The biological half-life of paracetamol in normal adults is about 2-3 hrs in the usual dosage range. It is shorter in children and longer in neonates and cirrhotic patients.
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