Evaluation of the pharmacoeconomic literature.

Pharmacoeconomics identifies, measures, and compares the costs and consequences of pharmaceutical products and services. The cost effectiveness of a pharmacotherapy in a particular indication depends on the molecular configuration of the drug, its safety and efficacy, and local market factors such as the acquisition cost of the drug, the cost of a hospital bed, physician fees and nursing time. The types of study include cost minimisation, cost effectiveness, cost utility, cost benefit and cost of illness. Modelling studies are used to predict long term economic consequences of therapy. Retrospective studies apply local costs to clinical trials that may be international in scope. Full prospective pharmacoeconomic studies provide more complete information but are rare and expensive to perform. The principles of pharmacoeconomics are illustrated by 2 retrospective case studies from the literature. In the first study, ondansetron was compared with metoclopramide on the basis of efficacy and tolerability inferred from a previous well controlled clinical trial. A range of economic outputs provided answers from several perspectives. In the second study, a sound pharmacoeconomic analysis of corticosteroids in paediatric asthma used a comparator therapy that is now deemed clinically inappropriate. The case studies illustrate how conclusions from pharmacoeconomic studies must be interpreted with caution before they can be applied in a particular clinical setting.