geriatrics
Pharmacokinetics in Older Adults
Distribution
With age, body fat generally increases and total body water decreases. Increased fat increases the volume of distribution for highly lipophilic drugs (eg,diazepam,chlordiazepoxide) and may meaningfully increase their elimination half-lives. Serumalbumindecreases and alpha 1-acid glycoprotein increases with age, but the clinical effect of these changes on serum drug binding varies with different drugs. In patients with an acute disorder or malnutrition, rapid reductions in serumalbuminmay enhance drug effects because serum concentrations of unbound (free) drug may increase.Phenytoinandwarfarinare examples of highly protein-bound drugs with a higher risk of toxic effects when the serumalbuminlevel decreases. 