NS 1209 (SPD 502) is a AMPA receptor antagonist.

NS1209 could be safely administered to rats undergoing electrically induced SE at doses up to 50 mg/kg followed by intravenous infusion of 5 mg/kg for up to 24h. NS1209 administered as a bolus dose of 10-50 mg/kg (i.p. or i.v.) followed by infusion of 4 or 5 mg/kg h (i.v.) for 2-24h effectively discontinued electrically induced SE in all animals within 30-60 min, and there was no recurrence of SE after a 24-h infusion. Kainate-induced SE was similarly blocked by 10 or 30 mg/kg NS1209 (i.v.). To compare the efficacy and neuroprotective effects of NS1209 with those of diazepam (DZP), one group of rats received DZP (20 mg/kg, i.p. and another dose of 10 mg/kg 6h later). By using the administration protocols described, the anticonvulsant effect of NS1209 was faster and more complete than that of DZP. NS1209 treatment (20 mg/kg bolus followed by 5 mg/kg h infusion for 24 h) was neuroprotective against SE-induced hippocampal neurodegeneration, but to a lesser extent than DZP.