Potentially undesirable prescribing and drug use among the elderly. Measurable and remediable.

Forty-seven patients older than 65 years were randomly selected for structured chart review of all long-term medications documented during the prior year and the number of instances of potentially undesirable prescribing for each patient. A trained nurse subsequently made home visits to assess all long-term medications used regularly during the same period. Forty-five percent of elderly patients had one or more instances of potentially undesirable drug use, all of which appeared to be readily remediable. Commercial drug interaction software identified less than half of the potentially undesirable instances.