An ABC of drug-related problems

The problems relating to the use of medicines are manifold. They may differ in pharmacological, pathological, epidemiological and legal respects, and may have different consequences, for example, as regards scientific study, regulation or rational use. Pharmacovigilance is concerned with all such pr oblems: adverse effects and interactions as well as problems relating to in effectiveness, inappropriate use, counterfeiting, dependence or poisoning. Practically all medicine-related problems can be classified in one basic sy stem, taking into account their characteristics and distinctions. This syst em distinguishes between appropriate and inappropriate drug use, dose-relat ed problems, and types A ('drug actions'), B ('patient reactions') and C (' statistical') adverse effects. This classification may serve as an educatio nal tool and may be useful in when choosing a study method and for the desi gn of effective strategies in pharmacovigilance.