Psychotropic drugs and the aging patient

Patients older than age 65 currently compose 13% of the US population, yet they receive 35% of all prescribed medications. In older patients, the complications of psychotropic drugs alone constitute a highly significant health problem. Pharmacokinetic and pharmacodynamic differences secondary to age or illness require careful consideration. Accumulation of drug might result from declining cardiovascular or renal function alteration of body composition, or genetic or acquired inhibition of drug metabolism. As patients age, there is a general reduction in homeostatic mechanisms such as postural control, orthostatic circulatory responses, and visceral muscle function that may result in adverse drug experiences. Specific receptor and neurotransmitter changes associated with senescence include reductions in central cholinergic and dopaminergic activities that lead to greater sensitivity to medications acting on these systems. Clinical vigilance is particularly important when prescribing newly available antidepressants and antipsychotics, since typically these medications are not systematically evaluated in older subjects before their release.