Pharmacovigilance (PV) is the pharmacological science relating to the detection, assessment, understanding and prevention of adverse effects, particularly long term and short-term side effects of medicines.

“pharmacon” means drug, and “vigilare” means to keep awake, alert, or to keep watch
Generally speaking, pharmacovigilance is the science of collecting, monitoring, researching, assessing and evaluating information from healthcare providers and patients on the adverse effects of medications, biological products, vaccines, blood products, medical devices, herbal & traditional medicines with a view to:

  • Identifying new information about hazards related to medicines
  • Preventing harm to patients

Pharmacovigilance is particularly concerned with the adverse drug reactions (ADR), which are officially described as “A response to a drug which is noxious and unintended, and which occurs at doses normally used… for the prophylaxis, diagnosis or therapy of disease, or for the modification of physiological function.”

Adverse drug reactions are a serious health problem.
They are among the top ten leading causes of death with 100,000 people dying each year and result in $3.6 billion a year in health care costs.

History of PV :

The first major drug related disaster recorded involved Sulfanilamide elixir responsible for the death of 107 children as early as 1937. This was followed by many more such cases such as that of thalidomide (1961), practolol (1974), phenformin (1982) to mention but a few.

It was after the thalidomide incident in 1961 that some systematic efforts began in the direction of addressing issues of drug safety.

The 16th World Health Assembly (1963) adopted a resolution that reaffirmed the need for early action in regard to rapid dissemination of information on ADRs and led, later, to creation of the WHO Pilot Research Project for International Drug Monitoring in 1968.

The purpose of this was to develop an internationally applicable system, for detecting previously unknown or poorly understood adverse effects of medicines. The practice of the science of pharmacovigilance emerged as a result of these modest beginnings.

Why Pharmacovigilance?

The information collected during the pre-marketing phase of a medical drug is inevitably incomplete with regard to possible adverse reactions:

  • Tests in animals are insufficiently predictive of human safety
  • Patients in clinical trials are selected and limited in number, the conditions of use differ from those in clinical practice and the duration of trials is limited
  • Information about rare but serious adverse reactions, chronic toxicity, use in special groups (such as children, the elderly or pregnant women) or drug interactions is often incomplete or not available

What are the major aims of Pharmacovigilance?

Pharmacovigilance is concerned with the detection, assessment and prevention of adverse reactions to drugs. Major aims of pharmacovigilance are:

  1. Early detection of hitherto unknown adverse reactions and interactions
  2. Detection of increases in frequency of (known) adverse reactions
  3. Identification of risk factors and possible mechanisms underlying adverse reactions
  4. Estimation of quantitative aspects of benefit/risk analysis and dissemination of information needed to improve drug prescribing and regulation.

Terms commonly used in Pharmacovigilance:

  • Benefits are commonly expressed as the proven therapeutic good of a product, but should also include the patient’s subjective assessment of its effects
  • Risk is the probability of harm being caused, usually expressed as a percent or ratio of the treated population; the probability of an occurrence
  • Harm is the nature & extent of actual damage that could be caused. It should not be confused with risk
  • Effectiveness is used to express the extent to which a drug works under real world circumstances, i.e., clinical practice (not clinical trials).
  • Efficacy is used to express the extent to which a drug works under ideal circumstances (i.e., in clinical trials)


The WHO Program for International Drug Monitoring provides a forum for WHO member states that includes India to collaborate in the monitoring of drug safety.Within the Program, individual case reports of suspected adverse drug reactions are collected and stored in a common database, presently containing over 3.7 million case reports.

Since 1978 the Uppsala Monitoring Center (UMC) in Sweden has carried out the Program.
The Uppsala Monitoring Center is responsible for the collection of data about adverse drug reactions from around the world, especially from countries that are members of the WHO including India.

Member countries send their reports to the Uppsala Monitoring Center where they are processed, evaluated and entered into the WHO International Database. When there are several reports of adverse reactions to a particular drug this process may lead to the detection of a signal — an alert about a possible hazard communicated to member countries. This happens only after detailed evaluation & expert review.

These ADR reports are assessed locally and may lead to action within the country. Through membership of The WHO International Drug Monitoring Program, a country can know if similar reports are being made elsewhere. (The European Union also has its own scheme.)
India is a country with a large patient pool and healthcare professionals, yet ADR reporting is in its infancy.

The National Pharmacovigilance Program (NPP) was launched on November 23, 2004 by the Government of India to collect ADR reports across the country and create awareness about pharmacovigilance. So far very few reports have been sent to UMC’s Vigibase, which is relatively a less figure considering the number of healthcare professionals in our country.

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