Current Methods of Pharmacovigilance

CURRENT METHODS OF PHARMACOVIGILANCE

Pharmacoepidemiology is the study of the use of, and effects of, drugs in large numbers of people. As the term implies, this form of enquiry uses the methods of epidemiology; it is concerned with all aspects of the benefit–risk ratio of drugs in populations. Phar-macovigilance is a branch of pharmacoepidemiology but is restricted to the study, on an epidemiological scale, of drug events or adverse reactions.

‘Events’, in this context, are happenings recorded in the patient’s notes during a period of drug monitor-ing; they may be because of the disease for which the drug is being given, some other intercurrent disease or infection, an adverse reaction to the drug being moni-tored or the activity of a drug being given concomitantly. They can also be because of drug–drug interactions.

Public health surveillance methods are used to identify new signals of possible ADRs. Studies in pharmacoepidemiology are intended to be either ‘hypothesis-generating’ or ‘hypothesis-testing’ or to share these objectives. Hypothesis-generating studies, with a recently marketed drug, aim to detect unex-pected ADRs; hypothesis-testing studies aim to prove whether any suspicions that may have been raised are justified.