Stimulation of oxidative drug metabolism by parenteral refeeding of nutritionally depleted patients.

To determine whether intravenous nutritional repletion can influence oxidative drug metabolizing capacity, antipyrine metabolism was studied in 6 malnourished patients on the second day of a 2-day baseline period and on the last day of two sequential, 8-day intravenous nutritional repletion periods. During the baseline period they received 5% dextrose, 440 kcal per day, intravenously. During the repletion periods they received 20 mg of nitrogen per kilocalorie of baseline resting energy expenditure and, in random order, dextrose to provide a total caloric intake of either 0.95 or 1.75 times baseline resting energy expenditure. There were no statistically significant differences between the high- and low-dextrose repletion regimens in their effects on antipyrine metabolism. Seven days of nutritional repletion resulted in a 42% decrease in mean half-life (range 12%-52%) and an 87% increase in mean metabolic clearance rate (range 29%-155%) for antipyrine. An additional 8 days of nutritional repletion resulted in no further change in these pharmacokinetic parameters.