The acknowledgement of the significance of Adverse Drug Reporting (ADR) is critical for India in the interest of the patients. Whilst a prescription drug has its therapeutic effects it carries with it specific side effects. Pharmacological/toxic effect is only defined by dose quantity and may differ from patient to patient. Theoretically, each drug can be toxic. However, there are efficient mechanisms to tackle both expected and unexpected adverse drug reactions. The principal task of Regulatory Agencies is to ensure safety of the medication medicines. The post marketing surveillance (PMS) is mandatory for safety implications during drug development and marketing. During PMS, the suspected unexpected serious adverse reactions (SUSAR) are reported, which helps to update the safety parameter of the drug.

What is pharmacovigilance?
● Collection & collation of data related to the detection, assessment, understanding, and prevention of adverse events.
● Identifying new information relating to hazards associated with medicines in an attempt to prevent harm to patients.
● Post-marketing surveillance.

International scenario
A scientific model to support excellence in pharmacovigilance has been developed by ICH through discussions with experts in the field. The model represents a long-term vision of how pharmacovigilance may be conducted in the future. So far it has been developed without any consideration of the constraints of resources or the need for legislative change. Although the vision is holistic, it would only be possible to test and implement parts of the model in a piece-meal fashion.

Indian scenario
India's Drug Control Department within the Ministry of Health & Family Welfare initiated the establishment of a nationwide network to build a comprehensive pharmacovigilance data system in 2004. The National Pharmacovigilance Advisory of the Director General of Health Services and the Drug Controller General of India (DCGI), function as the member secretary of the Committee. Based at the Central Drugs Standard Control Organization, NPAC was assigned the primary responsibility of setting up the system to monitor the pharmacovigilance programme throughout the country. The National Pharmacovigilance Programme is based on the recommendations made in the WHO document titled "Safety Monitoring of Medicinal Products - Guidelines for Setting Up and Running a Pharmacovigilance Centre".

Causality assessment is the method by which the extent of relationship between a drug and a suspected reaction is established. Currently, a wide variety of causality assessment scales exist. The scale attributes clinical events to drugs in individual patients or in case reports, each with their own advantages and limitations. The Naranjo's scale and the WHO scale of assessment are the most commonly used scales.

Adverse Drug Reactions are the fourth to sixth leading cause of death among hospitalized patients and it occurs in 0.3% to 7% of all hospital admissions. The incidence of serious ADRs is 6.7%. There is a rapid increase in the number of new drugs entering the market from the last few decades. India being the second most populated country has over one billion potential drug consumers, and no amount of pre-clinical and clinical data is sufficient to conclude the complete safety of a drug. In this scenario, it becomes necessary to report any untoward reaction of any pharmaceutical product to assess its safety and efficacy to ensure maximal patient health. In India, general practitioners, with a large outpatient base tend to be among the first ones to use the drugs entering the market. Hence, they are in the best position to assess the adverse drug reactions associated with drugs.

Importance of post marketing surveillance and ADR reporting
Tests in animals are insufficient to predict human safety. Patients used in clinical trials are selected and limited in number. The conditions for use differ from those in clinical practice and the duration of trials is limited. By the time the drug is licensed, exposure of less than 5000 human subjects to a drug, allows only the more common ADR to be detected. At least 30,000 people need to be treated to be sure that one does not miss the incidence of a very rare ADR (1 in 10,000) in exposed individuals. Information about rare but serious adverse reactions, chronic toxicity, and use in special groups (such as children, the elderly or pregnant women) or drug interactions is often incomplete or not available. Therefore, timely reporting of an adverse event by healthcare professionals can save the lives of many patients.

An ADR includes the following elements:
● Description of the adverse events or disease experience, including time to onset of signs or symptoms.
● Suspected and concomitant product therapy details (i.e. dose, lot number, schedule, dates and duration), including over-the-counter products, dietary supplements, and recently discontinued medications.
● Patient characteristics, including demographic information (e.g. age, race, sex), baseline medical condition, prior to product therapy, co-morbid conditions, use of concomitant medications, relevant family history of disease and presence of other risk factors.
● Documentation of
the diagnosis of the events, including methods used to make the diagnosis.
● Clinical course of the event and patient outcomes (e.g., hospitalization or death).
● Relevant therapeutic measures and laboratory data at baseline, during therapy, and subsequent to therapy, including blood levels, as appropriate.
● Information about response to de-challenge and re-challenge.
● Any other relevant information (e.g., other details relating to the event or information on benefits received by the patient, if important to the assessment of the event).

Conclusion
In India pharmacovigilance reporting is below 1% as against the world rate of 5%. This is due to lack of training and ignorance on the subject. The office of the DCGI has implemented a pharmacovigilance programme in India, which needs to be owned by the medical practitioners. An increase in drug safety concerns in recent years with some high profile drugs being withdrawn, has led to raising the bar by various stakeholders, more importantly by the regulatory authorities.

Proactive pharmacovigilance throughout the product life cycle is the way forward and the future direction for drug safety. It is a challenge to codify and standardize the act of signal detection and risk management in the context of clinical trials and post-marketing pharmacovigilance. Dynamic strategies to maintain and implement a robust pharmacovigilance system & timely reporting of an adverse event by healthcare professionals can save the lives of many patients.

-The Author is working with PharmaLeaf India Pvt Ltd, an international technical & regulatory consultancy in Bangalore