Tylenol Ext

Name: Tylenol Ext

Pharmacology

Mechanism of Action

Acts on hypothalamus to produce antipyresis

May work peripherally to block pain impulse generation; may also inhibit prostaglandin synthesis in CNS

Pharmacokinetics

Peak Plasma Time: 10-60 min (PO immediate-release); 60-120 min (PO extended-release); 6 hr (PO 500 mg, conventional tablet); 8 hr (PO 650 mg, extended-release tablet)

Peak Plasma Concentration: 2.1 mcg/mL (PO 500 mg, conventional tablet); 1.8 mcg/mL (PO 650 mg, extended-release tablet)

Onset: 1 hr

Distribution: 1 L/kg

Protein Bound: 10 to 25%

Metabolism: Liver (microsomal enzyme systems); conjugation (glucuronic/sulfuric acid)

Metabolites: N-acetyl-p-benzoquinoneimine, N-acetylimidoquinone, NAPQI; further metabolized via conjugation with glutathione

Half-life elimination: 1.25-3 hr (adolescents); 2-5 hr (children); 4 hr (infants); 7 hr (neonates); 2-3 hr (adults)

Excretion: urine (principally as acetaminophen glucuronide with acetaminophen sulfate/mercaptate)

(web3)