Sustained release pharmaceutical composition, and use of a pharmaceutical composition of extended release

PHARMACEUTICAL COMPOSITION OF PROLONGED RELEASE, AND THE USE OF A COMPOSITION FARMACeUTCIA release EXTENDED. The invention relates to a formulation for use once a day trazodone or trazodone derivative. The formulation contains trazodone or trazodone derivative and a controlled release excipient, such that, once orally admisnistradora, the trazodone or the trazodone derivative is maintained at a therapeutic plasma concentration of at least 1 hour to at least 24 hours after the initial administration. After administration, the initial therapeutic action fz made in the first hour and lasts at least about 24 hours. This therapeutic effect remains relatively and substantially stable rest period of 24 hours. The formulations may be used to treat depression and / or sleep disorders.