Pharmacokinetic characterization of amantadine in human brain tissue

Amantadine concentrations in human brain tissue were assessed in order to estimate population pharmacokinetic parameters using the computer program NONMEM. The elimination constant in brain tissue was determined to be 0.00447 [1/h], resulting in a t1/2 of 6.5 days for the mean patient in the population investigated (n = 19). An estimate of 65.5 L was obtained for the apparent volume of distribution. The elimination half-life of amantadine from brain tissue is much longer than from blood and is comparable to the previously investigated neuroleptic drugs haloperidol and levomepromazine.