Epilepsy in the elderly.

The elderly are the most rapidly growing segment of the population and the incidence of epilepsy is higher in the elderly than in any other age group. They have been subdivided into the "young old," 65-74 years, "middle old" 75-84 years, and the "old old," 85 years or older. But further subdivisions are needed: persons with only epilepsy, those with epilepsy and multiple medical problems, and the frail elderly. Thus, when considering therapy, one must tailor the interventions to nine categories: young old healthy, young old with medical problems, frail young old, old healthy, old with medical problems, frail old, old old healthy, old old with medical problems, and frail old old. The prevalence of antiepileptic drug (AED) use in community dwelling elderly is 1.5%; in the nursing home population it is 10%. Surprisingly, 3% have an AED newly prescribed after admission. Overall, 6.2% were using phenytoin, 1.8% carbamazepine, 0.9% valproic acid, 1.7% phenobarbital, and others combined, 1.2%. AEDs rank fifth among all drug categories as a cause of adverse reactions. There are very few data regarding the clinical use of AEDs in the elderly. The paucity of information makes it very difficult to recommend specific AEDs with any confidence that the outcomes will be optimal. An appropriate for elderly healthy may not be appropriate for elderly with multiple medical problems, and in frail elderly variable absorption may be a major problem. One of the major advantages of some newer AEDs is lack of drug interactions. Cost is an advantage of the older AEDs. Regardless of the AED chosen, one must use doses appropriate to the clearance of the drug, and AED levels, especially unbound (free) levels, must be monitored. The elderly nursing home resident may be more frail, be taking many medications, and have several concomitant illnesses, making them difficult to treat. The most commonly used AED, phenytoin, may not be the easiest or safest AED to prescribe in the elderly with multiple medical problems or the frail elderly.