Tanafen Mechanism of Action

Pharmacology: Pharmacodynamics: Paracetamol, a para-aminophenol derivative, is a peripherally acting analgesic with antipyretic and weak anti-inflammatory activity. Orphenadrine, an analog of diphenhydramine, is a skeletal muscle relaxant and is postulated to act on cerebral motor center or on the medulla through an atropine-like central action. It has anticholinergic, local anaesthetic effects and some antihistaminic effects.
Orphenadrine is used either as the hydrochloride or the citrate and doses are expressed in terms of the relevant salt.
Pharmacokinetics: Absorption: Paracetamol: Absorbed readily from GI tract; time to peak plasma concentrations: 10-60 minutes.
Orphenadrine: Absorbed readily from GI tract and after IM injection.
Distribution: Paracetamol: Distributed into most body tissues including breast milk, crosses the placenta; plasma-protein binding: negligible (but dose dependent).
Orphenadrine: May cross placenta.
Metabolism: Paracetamol: Undergoes hepatic metabolism; a minor metabolite, produced in minute amounts by cytochrome P450 isoenzymes in the liver and kidney, is usually removed by conjugation with glutathione, but may accumulate and cause tissue damage in paracetamol overdosage.
Orphenadrine: Metabolised to ≥8 metabolites.
Excretion: Paracetamol: Excreted in the urine mainly as the glucuronide and sulfate conjugates with <5% excreted unchanged; elimination half-life: 1-3 hrs.
Orphenadrine: Excreted mainly in urine and unchanged drug (small amounts); half-life: 14 hrs.