Gabapentin absorption: Effect of mixing with foods of varying macronutrient composition

OBJECTIVE: TO compare the oral absorption profile of gabapentin following administration of the contents of opened capsules that were mixed with food vehicles of varied macronutrient (protein) composition. DESIGN: An unblinded, randomized, single-dose, four-way crossover pharmacokinetic study in nine healthy adult men and women volunteers, METHODS: Following an overnight fast, a single 600-mg dose of gabapentin (2 x 300-mg Neurontin capsules) was given either as an intact capsule swallowed with 120 mt of tap water (control, phase I), or after capsule contents were opened and mixed with; 4 oz. of applesauce (phase II), 120 mt of orange juice (phase III), or 4 oz, of fat-free chocolate pudding (phase IV), Subjects fasted for 4 hours following drug ingestion, Serial venous blood samples were obtained over 24 hours to determine gabapentin serum concentrations. Pharmacokinetic variables including AUG, maximum serum concentration (C-max), and time to maximum serum concentration (t(max)) were calculated by using standard noncompartmental methods, Subjects served as their own controls, and were randomly crossed over following a minimum 7-day washout period Statistical analysis was performed by using ANOVA and Student's t-test where appropriate. RESULTS: NO statistically significant differences in any kinetic variable were found between any study arm. A trend was noted for a In a comparison of protein (phase IV) versus nonprotein phases (phases I-III), gabapentin AUC was 26% greater (47.28 +/- 14.65 vs. 37.43 +/- 9.78 mu g/mL.h; p = 0.03), and C-max was 32% higher (4.72 +/- 1.04 vs. 356 +/- 0.92 mu g/mL; p = 0.003). CONCLUSIONS: Opening and mixing the contents of gabapentin capsules does not significantly impair drug absorption. This may be a viable administration option for patients who are unable to swallow intact capsules. Dietary macronutrient composition (i.e., protein) may favorably influence gabapentin oral absorption.