Effect of food on ethambutol absorption.

The effect of food on the absorption of ethambutol hydrochloride tablets was investigated. Following an overnight fast, 11 normal volunteers ingested ethambutol hydrochloride tablets (15 mg/kg dosage) once while fasting and once immediately following a standardized breakfast. The sequence of administration was assigned randomly. Food and fasting trials were at least seven days apart. In both trials, blood samples were drawn at 1, 2, 3, 4, 6, 8, 12, and 24 hours after dosing. Ethambutol concentrations in plasma were determined by a gas-chromatography method. Completeness of absorption was assessed by calculation of the area under the 24-hour plasma concentration curve (AUC) for each subject after each mode of administration using a trapezoidal approximation. Within-subject difference in AUC between food and fasting conditions was evaluated using the Student's t test for paired data. There was no significant difference between the mean AUC-fasting and the mean AUC-food (p greater than 0.05). Food does not appear to influence the extent of ethambutol absorption.