There is provided pharmaceutical compositions for the treatment of pain e.g. short-term pain, which compositions comprise a mixture comprising:(a) microparticles of alfentanil, or a pharmaceutically acceptable salt thereof, which microparticles are presented on the surfaces of larger carrier particles(b) a water-soluble weak base and(c) a compound which is a weak acid, which acid is presented in intimate mixture with the microparticles of alfentanil or salt thereof.The composition may further comprise a disintegrant. The acid is preferably citric acid.
