Cognitive decline secondary to a variety of dementia diagnoses presents increasingly significant health and health care problems in the United States. Alzheimer's disease, in particular, is expected to afflict one in 45 Americans by the year 2058. Much research has focused on the assessment of drug therapy to treat the symptoms of cognitive decline, and in March 2008 the American College of Physicians and the American Academy of Family Physicians issued pertinent clinical guidelines based on a review of 58 clinical trials involving the five medications approved for the condition: the cholinergic neurotransmitter-modifying agents donepezil (Aricept), galantamine (Razadyne), rivastigmine (Exelon), and tacrine (Cognex), and a noncholinergic neurotransmitter-modifying agent, memantine (Namenda). Essentially, six assessment scales were used to evaluate the cognitive and global improvement in patients during the trials. Although a number of the studies demonstrated statistically significant results, the clinical significance of any improvement observed in them remains in question. Adverse effects associated with use of the medications include muscle cramps, insomnia, anorexia, diarrhea, nausea, emesis, weight loss, dizziness, and headache. Further, liver damage was associated with the use of tacrine.

The crux of the matter. In their clinical guidelines on drug treatment of dementia, the American College of Physicians and the American Academy of Family Physicians conclude that evidence of the clinical significance of any favorable effect of such therapy is modest and that there is no evidence indicating that any drug is superior to another in efficacy. The authors recommend that treatment be started after an evaluation of individual benefit and risk and that the agent be chosen according to its tolerability and adverse effects profile, ease of use, and cost. Further, the optimal duration of drug therapy for dementia is indeterminable, and additional research into its effectiveness is necessary.

JAH