The effect of age and frailty upon acetanilide clearance in man.

Six healthy young subjects (aged 23-32 years), six healthy elderly subjects (over 60 years) and six hospitalized long-stay geriatric subjects over 60 years received single oral doses of acetanilide. Acetanilide clearance was similar in the fit and frail elderly subjects at 26.4 +/- 2.5 and 26.3 +/- 3.6 l/h and significantly lower (p less than 0.05) than in the young subjects at 39.0 +/- 1.9 l/h. Liver volumes, measured by ultrasound, were significantly less in the elderly than in the young subjects, whether expressed in absolute terms or per unit body weight (p less than 0.05). When acetanilide clearance was expressed per unit volume of liver, no change occurred with age or frailty. These results suggest that a reduced liver size may be an important contributor to the reduced elimination of capacity limited drugs in elderly man.