The invention relates to a pharmaceutical dosage form having a breaking strength of at least 300 N and comprising (i) an ephedrine component selected from the group consisting of ephedrine, pseudoephedrine and the physiologically acceptable salts thereof, wherein preferably the weight content of the ephedrine component is within the range of from 0.1 to 60 wt.-%, relative to the total weight of the pharmaceutical dosage form； and (ii) a physiologically acceptable conversion inhibitor that is capable of inhibiting the chemical conversion ex vivo of the ephedrine component into methamphetamine.本發明係關於一種醫藥劑型，其斷裂強度為至少300N且包含：(i)麻黃素組分，該麻黃素組分係選自由以下組成之群：麻黃素、偽麻黃素及其生理學上可接受之鹽，其中較佳該麻黃素組分之重量含量相對於該醫藥劑型之總重量在0.1至60wt.-%範圍內；及(ii)生理學上可接受之轉化抑制劑，該生理學上可接受之轉化抑制劑能夠抑制該麻黃素組分離體化學轉化為甲基安非他命。
