Inhalers may be making asthma worse when they're used too often, researchers have discovered. Over time, inhalers not only become increasingly ineffective, they can even make the problem worse by forcing the release of chemicals such as histamine that cause lung airways to narrow, researchers from the University of Leicester in the UK have discovered. The researchers stress that their research has concentrated on 'reliever' therapies, which are designed to improve symptoms, as opposed to 'preventer' treatments that produce a protective effect over time. (Source: University of Leicester. http://www2.le.ac.uk/ebulletin/news/press-releases/2010-2019/2010/01/nparticle.2010-01-13.9318187830?searchterm=inhalers).