Drug safety in relation to efficacy: the view of a clinical pharmacologist.

The number of registered drugs, and drug expenditure are increasing rapidly in Europe, and within the European Union (EU) there are no longer any regulations requiring that new drugs have to be better than old ones. At the same time, pharmacoepidemiological studies in Europe and USA show that adverse drug reactions now may account for up to 10% of the admissions of patients to internal medicine wards at a cost of hundreds of millions of US dollars annually. This represents a considerable increase compared to 20 years ago. A partial explanation is the many shortcomings of many clinical trials and their relevance for health care. Adverse drug reactions are often poorly studied and documented in these studies and very seldom included in health economical analyses of the value of new drugs. Pharmacovigilance is product- rather than utilization-oriented and quite invisible in clinical medicine. This is regrettable, since up to 50% of adverse drug reactions (ADRs) are dose-dependent and thus preventable. Hopefully, the rapid progress in molecular and clinical pharmacogenetics will provide new tools for clinicians to choose and dose drugs according to the individual needs of patients.