The invention relates to an oral pharmaceutical dosage form providing resistance against dose dumping in aqueous ethanol and comprising a pharmacologically active ingredient embedded in a matrix material,wherein the matrix material comprises an alkyl cellulose and a heteropolysaccharide； andwherein the relative weight ratio of heteropolysaccharide to alkyl cellulose is within the range of from 1:20 to 20:1； andwherein the total content of alkyl cellulose and heteropolysaccharide is at least 35 wt.-%, relative to the total weight of the dosage form. A process of producing the dosage form and methods of using the dosage form, for example to treat pain, are also disclosed.
