Campostrini R, Zaccara G, Rossi L, Paganini M, Dorigotti A, Zappoli R
J Neurol. 1985;232(3):167-8. doi: 10.1007/BF00313894.
The cases of two epileptic identical twins are described, one of whom had presented an episode of valproate (VPA)-induced stupor associated with very high blood ammonia (NH3) concentrations. Both twins showed a similar marked increase of venous NH3 concentrations after the administration of a single loading dose of VPA (800 mg).