After a fall her husband contacted the family doctor and me, and instructions were given to bring her to the emergency department. By the time she arrived she was in deep coma, with no response to pain. Her serum glucose level was 2.2 mmol/L. The medication bottle was with her, so that the error was quickly identified. A diagnosis was made of metabolic coma secondary to hypoglycemia, and she was admitted to the intensive care unit for treatment. Miraculously, she recovered without residual organic mental deficits. The College of Physicians and Surgeons was contacted, and it advised that a report be submitted to the College of Pharmacy for appropriate action. Chlorpropamide instead of chlorpromazine has the potential for acute and fatal consequences. This is not the only serious error that has happened to one of my patients and those of immediate colleagues. However, there is no formal mechanism for reporting these incidents (as there is for adverse drug reactions) in order to compile figures and gain an overall picture of how often such mistakes are occurring. Each is dealt with on an individual basis. Knowing whether chlorpropamide and chlorpromazine have been incorrectly interchanged more frequently than the two times reported may support the case for changing similar drug names and, as Dr. Landis suggested, for helping "develop learning tools that would make physicians and pharmacists more aware of this potentially serious problem." In the meantime, we can continue to encourage patients to be informed about their medications, and we should be receptive to reassessing prescriptions thoroughly when questions are raised.

Similar drug names worry OMA, American pharmacists A Ithough I wholeheartedly agree with the Newsbrief item in CMAJ (1990; 143: 401) Canadian pharmacists are equally concerned about medications that look and sound alike. The most recent example that comes to mind is Lasix v. Losec. Moreover, there are groups of pharmacists in community and hospital practice who do monitor and report problems to the Drugs Directorate of the Department of National Health and Welfare, the Pharmaceutical Manufacturers Association of Canada and the pharmaceutical licensing bodies in each province. There may be some merit in looking at this as an issue affecting all health care professionals nationally. A joint review of drug names by a multidisciplinary committee would combine a numer of perspectives and be very useful. One has only to think of the long line of cephalosporins to realize that physicians, nurses and pharmacists must be equally concerned about this problem. The confusion over similar drug names does not seem to be the responsibility of any one country or group of people. However, it is important to inform those responsible for naming compounds that there is a great deal of risk to patients if drug names look or sound alike. Gery R. King, BSP President Canadian Society of Hospital Pharmacists Toronto, Ont.

Cognitive impairment in the elderly

Jean E. Porter, MD, FRCPC

Coordinator Psychiatric Consultation-Liaison Service Mississauga Hospital Mississauga, Ont. 196

CAN MED ASSOC J 1991; 145 (3)

I t was interesting to note the very high levels of cognitive vimpairment quoted in "Cog-

nitive and behavioural impairment among elderly people in institutions providing different levels of care," by Drs. Louise Teitelbaum, M. Lynne Ginsburg and Robert W. Hopkins (Can Med AssocJ 1991; 144: 169-173). Using the Mini-Mental State Examination they found a score of less than 24 (indicative of moderate or severe cognitive impairment) in 84% of residents of a nursing home, 84% of those in a home for the aged and 96% of patients in a psychiatric hospital. Although it is not surprising that the number of impaired patients in psychogeriatric wards was so great the figures from the nursing home and especially from the home for the aged are much higher than Nancy Moulton and I have found in our work in rural areas of Newfoundland (unpublished data), and we wonder whether Teitelbaum and associates' figures are representative of the situation across Canada. Using the Canadian Mental Status Questionnaire developed by Robertson, Rockwood and Stolee' we found the prevalence of moderate or severe cognitive impairment among residents (mostly psychogeriatric patients) of a longstay hospital ward to be 77%, among people in a nursing home to be 50% and among those living at home to be 9%. We tested people aged 70 years and older. The total prevalence of moderate or severe dysfunction in the population was 1 1%, a rate not significantly different from Jeans and colleagues' estimate from surveys done in several parts of Canada.2 Problems with comparing surveys of cognitive function have been the widely different methods used and the different populations studied; moreover, estimated prevalence rates are affected by the cutoff points and diagnostic criteria of the various tests for dementia.3 Had we moved the cutoff point between mild and moderate cognitive impairment For prescribing information see page 232 -