Prescribing patterns for older heavy drug users living in the community.

We report an analysis of prescription drugs claimed under a government-sponsored, universal Pharmacare program for community-dwelling adults aged greater than or equal to 50 years in Manitoba during 1975, 1978, 1981, and 1984. We limited our analysis to claimants who reported over six drugs in a year in order to control for effects of inflation and a changing deductible. The median number of prescribed drugs and the percent of claimants over age 50 years receiving prescriptions from multiple physicians decreased during the course of our study. In this sample of heavy drug users, age and sex did not consistently correlate with overall drug use, although there was correlation for specific drug groups. The relative ranking of prescribed drugs changed over the years, although benzodiazepines, thiazide diuretics, topical steroids, and codeine-containing analgesics remained near the top. Barbiturates and topical antibiotics showed the greatest drop in prescription rates; acetaminophen and beta-blockers increased the most. Using these community data, we project the prevalence of drug-related adverse events to be highest with beta-blockers, nonsteroidal antiinflammatory drugs, thiazide diuretics, and benzodiazepines.