Probenecid pretreatment enhances anticonvulsant action of NBQX in mice.

NBQX (2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo(F)quinoxaline) was studied following intravenous administration to mice. Maximal electroshock seizures were suppressed by low doses of NBQX (ED50 = 13 mg/kg) but effects had dissipated by 10 min after a dose of 25 mg/kg. Coadministration of the transport inhibitor probenecid (p-(dipropylsulphamoyl)-benzoic acid) enhanced and prolonged the anticonvulsant action of NBQX and also enhanced and prolonged ataxia. NBQX may be rapidly eliminated by a process sensitive to probenecid.