SB-204269 is an anticonvulsant agent under development by SmithKline Beecham, It is in phase II clinical trials as a potential treatment for epilepsy [243338]. The compound is structurally-related to the benzopyran ATP-sensitive potassium channel (KATP) opener, cromakalim, but has opposite stereochemistry. No KATP activators, however, show significant affinity for the binding site of SB-204269 and the mechanism of action of the latter is not thought to involve KATP. SB-204268, the opposite enantiomer, shows no anticonvulsant activity [226615]. SB concludes that SB-204269 represents a mechanistically novel anticonvulsant agent.