Monitoring medicines use: the role of the clinical pharmacologist.

Appreciation of the potential of newly marketed medicines to produce both benefit and harm has increased the role of the clinical pharmacologist. Pharmacoepidemiology applies epidemiological reasoning, methods and knowledge to the study of the uses and effects of drugs in human populations. Pharmacovigilence identifies and then responds to safety issues about marketed drugs. Whilst adverse drug reaction (ADR) reporting systems can identify potential problems with drugs, determination of causation requires population-based studies of adverse events (including information from large clinical trials), which attempt to link unequivocally the adverse outcome to the drug in question. Pharmacovigilance is closely linked to postmarketing surveillance and is important for determining issues such as the long-term effects of drugs, identification of low-frequency ADRs, the effectiveness of drugs for their licensed indications or in new indications and other factors which may modify the efficacy and effectiveness of the drug in question. The related field of drug utilization developed in parallel with the study of adverse drug reactions, in recognition of the dramatic increase in the marketing of new drugs, the wide variations in the patterns and extent of drug prescribing, the growing concern about ADRs and the increasing costs of drugs. With the ever increasing number of recognized adverse effects of drugs, prescribing errors, patients' expectations concerning drug safety and the need for appropriate new drug appraisal, the clinical pharmacologist will play an important role both in the introduction of new drugs and in improving the safe and effective use of established drugs.