Escinal Mechanism of Action

Pharmacokinetics: Escitalopram absorption is almost complete and independent of food intake. The apparent volume of distribution after oral administration is about 12 to 26 L/kg. The plasma protein binding is below 80% for escitalopram and its main metabolised  in the liver to the demethylated metabolites. Both of these are pharmacologically active. Alternatively, the nitrogen may be oxidised to form the N-oxide metabolite. Both parent substance and metabolites are partly excreted as glucuronides. After multiple dosing the mean concentrations of the demethyl and didemethyl metabolites are usually 28-31% and, 5%, respectively, of the escitalopram concentration. Biotransformation of escitalopram to the demethylated metabolite is mediated primarily by CYP2C19.
Some distributuin by the enzymes CYP3A4 and CYP2D6 is possible. The elimination half-life after multiple dosing is about 30 hours and the oral plasma clearance is about 0.69L/min. The major metabolites have significantly longer half-life. Escitalopram and major metabolites have a significantly longer half-life. Escitalopram and major metabolites are assumed to be eliminated by both the hepatic (metabolic) and the renal routes, with part of the dose excreted as metabolites in the urine.