Fig. 7. Plasma concentrations of naproxen (A ) or gabapentin (B ) after administration via gavage of the drug alone or in combination. Symbols represent the mean ± SE of determinations in 8–16 rats. The doses on the abscissa represent the actual dose of naproxen (N) or gabapentin (G) administered alone or in the mixture. Only the plasma concentration of gabapentin for the highest dose of the 1:50 gabapentin:naproxen (G:N) mixture is illustrated because lower doses yielded plasma concentrations below the limit of detection of this assay method.