Sign Out
Pharmacology: Pharmacodynamics: Donepezil, a reversible inhibitor of the enzyme acetylcholinesterase, is postulated to exert its therapeutic effect by enhancing cholinergic function.
Pharmacokinetics: Donepezil is well absorbed. The rate and extent of absorption are not influenced by food intake. Maximum plasma levels are reached approximately 3-4 hours after oral administration. Following multiple-dose administration, steady state concentration (~14.2 ng/mL) is reached approximately within 15 days. Donepezil is approximately 96% bound to human plasma protein, 75% bound with albumin and approximately 21% bound with alpha1-acid glycoprotein. Steady state volume of distribution (VolD) is 12 L/kg of body weight. Donepezil undergoes first pass metabolism by cytochrome P450 isoenzyme CYP2D6 and CYP3A4 and undergoes glucoronidation to four major metabolites, two of which are known to be active. Donepezil is both excreted in the urine and feces, elimination half life is about 70 hours.
