DRUG-THERAPY FOR GERIATRIC DEPRESSION

Depression is a common problem in elderly patients. The identification and treatment of depression may be more complex in older than in youn ger patients because of co-existing illnesses and concurrent drug ther apy. In addition, a variety of medical conditions and drugs can cause depression. The pharmacology and pharmacokinetics of the cyclic antide pressants have been extensively studied. These agents are hepatically metabolised, often to an active agent. The clearance of the parent com pound and the active metabolite(s) may be reduced in elderly patients, causing drug accumulation and increased toxicity. The cyclic antidepr essants interact with a variety of neurotransmitters and their recepto rs. While these effects explain many of the adverse effects of the cyc lic antidepressants, it is not clear whether the noradrenergic and ser otoninergic effects of such drugs explain their antidepressant effects . Cyclic antidepressant therapy is associated with a variety of advers e effects, including sedation, anticholinergic effects and effects cau sed by alpha-adrenergic blockade. The cyclic antidepressants differ in their relative ability to cause these adverse effects. The newer cycl ic antidepressants such as the selective serotonin reuptake inhibitors are relatively free of sedative and anticholinergic effects, but caus e insomnia, nausea and possibly cardiac arrhythmias. All cyclic antide pressants appear to be equally effective. Therefore, the choice of a c yclic antidepressant for a specific patient must be based on several f actors, including the risk of adverse effects. In elderly patients, th e initial dose of cyclic antidepressants should be lower than the usua l dose recommended for younger adults, and titrated slowly. All antide pressants require at least 2 to 3 weeks for their antidepressant effec ts to be seen. Because depression is a relapsing disease, maintenance antidepressant therapy may be indicated to reduce the risk of recurren t depression. The monoamine oxidase (MAO) inhibitors are effective ant idepressants, especially in atypical depression. However, the adverse effects and risk of potentially lethal drug interactions of the older agents preclude their routine use. However, the new reversible MAO inh ibitors may prove to be a well tolerated alternative in older patients . Antidepressant therapy should not be avoided simply because of a pat ient's age. However, the clinician must be conservative in the use of cyclic antidepressants in elderly patients and monitor closely for adv erse drug reactions.