Oral gabapentin disposition in patients with epilepsy after a high-protein meal

Purpose: To study the interaction between gabapentin (GBP) and high-protein meals, 12 patients with epilepsy were administered this drug both while in a fasting state and after a high-protein meal. Methods: After having acquired their informed consent, the patients (suffering from partial complex seizures resistant to other anticonvulsants) were randomly assigned to 2 groups of 6 subjects. Each subject was treated in a fasting state with a single 400 (group A) or 800 (group B) mg GBP oral dose. After 24 h, the GBP dose regimen was repeated, but was given after a high-protein meal. Serum GBP concentrations were measured by LC-Mass at baseline and 0.5, 1, 2, 3, 5, 7, 9, 12, and 24 h. Saliva GBP concentrations were determined at baseline and 2, 4, 8, and 12 h. GBP urinary excretion was determined at 0-4, 4-8, and 8-12 h intervals. The following kinetic parameters were calculated: area under the concentration time curve from zero time to 24 h after the dose, AUC 0-24 h; maximal serum concentration, C-max; time to the maximal serum concentration, T-max; absorption rate constant, ka; elimination rate constant, beta; elimination half-time, t1/2 beta. Student's t test for paired data, with significance assigned at P < 0.05, was used. Results: No statistically significant differences were seen in GBP serum or saliva concentrations or in its urinary excretion (both in A or B group) between fasting and after the high-protein meal. Conclusions: High-protein meals do not seem to interfere with oral disposition of GBP.