Compositions for overcoming resistance to tramadol

Abstract

Disclosed herein is a composition for oral administration of O-desmethyltramadol that is effective for overcoming resistance to tramadol in patients.

What is claimed is: 
     
         1 . A sustained release oral solid dosage formulation consisting of O-desmethyltramadol or a pharmaceutically acceptable salt thereof homogenously dispersed in a sustained release matrix delivery system in the form of a tablet or capsule, wherein the sustained release matrix system consists of a polymer selected from polysaccharide, acrylic resin, polyalkylene glycol, polyvinyl acetate, polyvinylpyrrolidone, protein-derived materials, colloidal silica, and mixtures thereof, microcrystalline cellulose; and, optionally, one or more pharmaceutical excipients selected from the group consisting of preservatives, buffers, salts and magnesium stearate; wherein the sustained release matrix system provides an in vitro dissolution of between 15 and 74% O-desmethyltramadol released after 1 hour and between 79 and 105% O-desmethyltramadol released after 12 hours, and upon administration to a human subject provides a controlled release of O-desmethyltramadol over at least about 8 hours.