• Clinical pharmacology
• prescribing
• public health policy

Prescribing is an essential part of physicians' daily work, a professional and ethical responsibility. It implies a complex decision-making process that is conditioned not only by physicians' academic and cultural background but also by other factors such as pharmaceutical market width, medicines promotion by the pharmaceutical industry, access to independent information, medical care context in which the physician works and continuous education programmes or incentives from healthcare provider organisations. Left to pharmaceutical market whims, prescribing is known to be shifted towards newer and usually more expensive medicines.1 The most appropriate drugs for patients should be selected according to principles well described in the WHO ‘Guide to good prescribing’, such as comparative effectiveness, safety, convenience and cost.2 The rational use of medicines is defined as ‘the prescription of the most appropriate medicine to the patient in need of them, at an adequate dose and time duration, and giving to the patient the needed information to use them’; it was agreed at a WHO conference in 1985.3 Although rational drug prescription does not guarantee that medicines expenditure is limited, this concept may represent a crucial step towards a more efficient use of drugs.4

Intensive marketing of new and more expensive drugs, demographic changes, rising patient expectations or stricter clinical targets have pushed pharmaceutical expenditure to increase more rapidly than any other component of health care.5 Concomitantly, the excessive …