RECENT ADVANCES IN GERIATRIC PSYCHOPHARMACOLOGY

Psychopharmacotherapy of the elderly must take into account the effect s of age-related changes in the structure and function of the brain an d various organs. In general, older people are more sensitive than you ng people to both the therapeutic and toxic effects of psychotropic me dications, necessitating lower doses and longer dosage intervals. This holds true for the treatment of 5 major types of psychiatric illness (depression, bipolar disorder, anxiety, psychotic disorders and dement ia). The tricyclic antidepressants, although efficacious, inexpensive, and backed by 30 years of experience, are less well tolerated by the elderly than are newer antidepressants such as the selective serotonin uptake inhibitors. Problems with monoamine oxidase (MAO) inhibitors, including orthostatic hypotension and restrictions in diet and other m edication use, have been overcome by the advent of reversible selectiv e inhibitors of MAO-A, but the efficacy of these in the elderly has ye t to be proven in clinical trials. Lithium remains the mainstay for th e treatment of bipolar disorder. However, careful dosing and monitorin g of plasma lithium concentrations are required in the elderly due to changes in pharmacokinetics and pharmacodynamics which make older pati ents very sensitive to the toxic effects of this medication. Similarly age-related changes in the pharmacokinetics and pharmacodynamics of t he benzodiazepines, the most frequently prescribed medications for anx iety in the elderly, result in recommendations for lower doses and pre ferential use of those agents metabolised by conjugation (e.g. oxazepa m). Buspirone, a partial serotonin 5-HT1A-agonist which is better tole rated than benzodiazepines in the elderly, may be used as an alternati ve. The elderly are extremely sensitive to extrapyramidal adverse effe cts which the typical antipsychotics (neuroleptics) exhibit to varying extents. The selection of a suitable agent for the treatment of a psy chotic disorder should be based upon the adverse effect profile of the drug and the specific symptoms and situation of the patient. The newe r atypical antipsychotics, clozapine and risperidone, have yet to be w ell-studied in the elderly. Dementia, exemplified by Alzheimer's disea se, is almost exclusively an illness of the elderly. Only one medicati on, tacrine, has been approved for its treatment, based on extensive b asic research and positive results of several clinical trials. Its lon g term benefits have yet to be determined and it has several adverse e ffects, including a tendency to increase liver enzymes to the extent t hat the medication has to be discontinued. Discovery and development o f new medications for other psychiatric disorders in the elderly have been neglected for various research and ethical reasons which will hav e to be overcome if progress in geriatric psychopharmacology is to con tinue.