THEOPHYLLINE DISPOSITION FOLLOWING PARENTERAL-FEEDING OF MALNOURISHEDPATIENTS

OBJECTIVE: To investigate the effect of parenteral nutrition on theoph ylline disposition in malnourished patients. DESIGN: Before-after tria l. SETTING: Tertiary care center. PATIENTS: Ten patients with historic , anthropometric, and laboratory evidence of malnutrition. INTERVENTIO NS: Patients received two 5-mg/kg intravenous infusions of theophyllin e separated by at least 48 hours of glucose-based parenteral nutrition providing the entire estimated nutritional requirements. MAIN OUTCOME MEASURES: Following each theophylline administration, serum theophyll ine samples were collected over a 24-hour period for delineation of ma ximum plasma concentrations, volume of distribution, elimination rate constant, clearance, and area under the curve. RESULTS: Peak plasma th eophylline concentrations were significantly lower prior to feeding (5 .3 mumol/L, 95 percent confidence interval [CI] 0.78-10.0 mumol/L, p = 0.028). Volume of distribution decreased after parenteral feeding (0. 08 L/kg, 95 percent CI 0.006-0.15 L/kg, p = 0.037). The elimination ra te of theophylline increased after parenteral feeding reflected by an increase in the elimination rate constant (0.06 h-1, 95 percent CI 0.0 1-0.10 h-1, p = 0.023). CONCLUSIONS: This study suggests that parenter al nutrition using a glucose-based solution acutely influences theophy lline disposition in malnourished patients.