Phensuximide is an orally active succinimide antiepileptic and anticonvulsant agent. Phensuximide inhibits cyclic AMP and cyclic GMP accumulation in depolarized brain tissue. Phensuximide can be used for the study of seizure and petit mal.IC50 & Target: IC50: cyclic AMP and cyclic GMP accumulation[2]In Vitro: Phensuximide produce depolarization-induced accumulation of cyclic GMP or cyclic AMP levels with ID50 values of 8.00 mM or 6.20 mM in incubated slices of mouse cerebral cortex[2].Phensuximide (0.5-2.0 mM) has the ability to competitively inhibit mephenytoin 4-hydroxylase activity in human liver microsomes, the Ki and Km values are 559 μM and 235 μM, respectively.In Vivo: Phensuximide (intraperitoneal injection; 1.25 mmol/kg; single dose) induces mild changes in renal function, including: trace hematuria, increased proteinuria and decreased paminohippurate uptake in Sprague-Dawley rats.Phensuximide (intraperitoneal injection; 0.3 or 0.6 mmol/kg; 5-7 days) results in transient hematuria and proteinuria, but no change in the other renal function parameters studied. It is concluded that phensuximide produces mild, transient renal effects in Fischer 344 rats, and that the Fischer 344 rat is a suitable model for studying phensuximide-induced toxicity to the urinary tract.