J Chron Dis Vol. 36. pp. 75-84. 1983 Printed in Great Britam. All rights reserved 0021-968l~X3/0l0075-l0~03.00/0 Copyright 0 1983 Pergamon Press Ltd AGING AND HEAVY DRUG USE: A PRESCRIPTION SURVEY IN MANITOBA F.Y. Aoki, V.K. Hildahl, G.W. Large, P.A. Mitenko* and D.S. Sitar Geriatric Clinical Pharmacology Unit Departments of Medicine and Pharmacology University of Manitoba ABSTRACT A random sample of claimants under Manitoba’s Pharmacare plan provided information on the drugs prescribed for those individuals who spent more than $50 for drugs in 1978. More women than men were represented among the 412 claimants aged 50 to 64 (58% females), and more drugs were prescribed for women than men (8.38 L .34 vs. 7.17 + .33, mean f S.E.M., p < 0.02). For the 403 claimants aged 65 and older, the sex distribution matched that of the general population (55%), and the difference in number of drugs prescribed was not statistically significant (8.49 f .36 vs. 7.98 k .35). For the claimants aged 65 and older, the five most heavily prescribed drug categories were thiazide-type diuretics (prescribed for 51.6% of older claimants in 19781, benzodiazepines (40.0%), salicylates (26.8%), digoxin (22.6%) and codeine (20.8%). There were few differences in prescription frequencies between younger and older claimants, and these data indicate that drugs prescribed for heavy drug users do not change markedly as a function of age. KEY WORDS Aging; heavy drug use; prescription survey INTRODUCTION The old have more illness than the young, and their diseases tend to be multiple and chronic. Not surprisingly, more drugs are prescribed for the elderly, and, for example, the 11% of Saskatchewan’s population 65 years of age or older received 28% of all the prescriptions written in that province (Skoll, August & Johnson, 1979). Most geriatric patients derive real benefit from appropriate drug therapy, but the old are at greater risk of developing unwanted drug effects. Although they are made more sensitive to the effects of some drugs by the physiological and pathological changes that occur with aging, the heavy use of drugs by the elderly contributes substantially to this added risk. In a survey of 42 British geriatric units, adverse reactions were partly or wholly responsible for the hospitalization of 209 of the 1625 patients receiving prescribed drugs (Williamson and Chopin, 1980). *Address correspondence to P.A. Mitenko, M.D., Geriatric Clinical Pharmacology Unit, CC 427 Health Sciences Centre, 700 William Avenue, Winnipeg, Manitoba, Canada, R3E 023.