Drug use in homes for the aged. A comparison between mentally intact and mentally impaired residents.

The aim of this study was to analyze drug use in 347 residents in homes for the aged in Bergen, Norway. All drugs prescribed on a regular schedule were assessed, the prevalence of potentially harmful drug combinations, and inappropriately prescribed drugs were studied and related to mental capacity of the residents. Mental capacity was assessed by means of the Clinical Dementia Rating scale (CDR). The median number of drugs used was 4.0 (range 0-11, 95% CI 3.0-4.0). Mentally impaired residents consumed fewer drugs than mentally intact ones. In a logistic regression analysis the use of NSAIDS, beta-blockers and anxiolytics was significantly lower in mentally impaired residents (OR 0.37, 95% CI 0.17-0.80, OR 0.35, 95% CI 0.13-0.95, and OR 0.45, 95% CI 0.21-0.94, respectively), and the use of laxatives and vitamin B-12 higher (OR 2.19, 95% CI 1.04-4.62, and OR 5.08, 95% CI 1.11-23.25, respectively). Twenty percent of mentally intact and 21% of mentally impaired residents have potentially harmful two-by-two drug combinations, and drugs augmenting sedating properties were dominating. The prevalence of inappropriately used drugs was significantly lower in mentally impaired residents (20%) than in mentally intact ones (33%). Antidepressants with anticholinergic properties, benzodiazepines with long half-life and phenothiazines were the most frequent.