[Introduction to the theory of pharmaco-economics].

This article presents an overview of the principles of pharmaco-economic evaluation. A pharmaco-economic evaluation is a comparison of the costs and effects of at least two therapeutic strategies, including at least one drug. It is mostly useful if a new treatment is more effective and more costly than a reference one. The way the effects of treatments are expressed defines several types of analyses: cost minimisation, cost-effectiveness, cost-utility and cost-benefit. The costs measured can be direct (medical and non-medical) and indirect (tangible and intangible). The principle of decision analysis is illustrated.