Anticonvulsant activity in photosensitive baboons, Papio papio, of two new 1,5 benzodiazepines.

Two new 1,5 benzodiazepines have been evaluated acutely as anticonvulsants in baboons, Papio papio, with photosensitive epilepsy. BAU 426 (8-Chlor-6-[2-chlorphenyl]-4H-s-triazolo-[4,3-a] [1,5-benzodiazepin-5-[6-H]on) and BAU 500 (analogue of BAU 426 with [2-trifluor methylphenyl] substituted for [2-chlorphenyl]), 0.1--5.0 mg/kg, were administered i.v. to baboons with and without priming with D,L allylglycine. BAU 426 or BAU 500, 0.1--0.2 mg/kg, produced partial or transient protection against photically induced myoclonus or epileptic responses. Complete protection, in the absence of signs of sedation or acute neurological toxicity, was seen 1--4 h after 0.5--2 mg/kg. EEG changes typical of benzodiazepines were seen for 1--3 h and clinical signs of sedation with some muscular hypotonia were evident for 1 h after either drug, 5 mg/kg. Clinical trials are required to determine if these compounds are superior to 1,4 benzodiazepines as anticonvulsants.