A thermoformed, tamper-resistant pharmaceutical dosage form comprises: a) a pharmacologically active ingredient; b) a polyalkylene oxide having a weight average molecular weight of more than 200,000 g/mol; and c) a zinc component, wherein the content of said zinc component is at least 1 ppm, relative to the total weight of the pharmaceutical dosage form. When the pharmacologically active ingredient is effective against pain, the pharmaceutical dosage form may be used in a method of treating pain. When the pharmacologically active ingredient has abuse potential, the pharmaceutical dosage form may be used in a method of reducing the incidence of the abuse of said pharmacologically active ingredient.