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METHODOLOGICAL PROBLEMS

ASSOCIATED WITH STUDIES OF

DRUG METABOLISM IN THEELDERLY

R.E. VESTAL

The Capt. Marshall W. Wood Research Laboratory,

Veterans Administration M edical Center, Boise, ldaho 83702, USA

and

Divisions ofClinical Pha rmacology, Gerontology and Geriatrie Medicine,

University ofWa shin gton School ofM edicine, Seattle, Wa shin gton 98195. USA

Introduction

During the last decade geriatr ic clin ical pharmacology has become the focus of

considerable research effort. Th is is due , in part, to the realization that in most

developed countries the elderl y constitute 10% or more ofthe population, but spend

25 to 30% of total expenditures for drugs and drug products (Crooks, O'Malley &

Stevenson, 1976; Vesta l, 1978). These figures are likely to increase during the next

several decades. In add ition , the rate of adverse drug reactions is 2 to 3-fold higher in

elderl y pati ents than in young patients (Seidl, Thornton, Smith & Clough, 1966;

Hurwitz, 1969; Caranasos, Stewart & Cluff, 1974). Factors which may alter drug

disposition in the elderly have been exten sively reviewed (Crooks et al., 1976; Riche y

& Bender, 1977; Vestal , 1978; Q'Malley, Judge & Crooks, 1980), and will be discussed

only briefly in this paper. However, some ofthe important methodological problems

which confront clinical pharmacologists who conduct gerontological research will be

presented along with several pertinent examples from the literature.