A pharmaceutical composition for the treatment of acute pain by sublingual administration is described. The composition comprises an essentially water-free, ordered mixture of fentanyl or a pharmaceutically acceptable salt thereof in the form of microparticles which are adhered to the surface of carrier particles which are substantially larger than the particles of fentanyl, and are essentially water-soluble. In a preferred embodiment, the composition also contains a bioadhesion and/or mucoadhesion promoting agent. The invention also relates to the preparation of the composition, and to the use of the composition for the treatment of acute pain.