Pharmacovigilance (PV) is the science and activities relating to the detection, assessment, understanding, and prevention of adverse effects or any other drug-related problems. The term is derived from two words: “Pharmakon” (Greek) meaning drug, and “Vigilare” (Latin) meaning to keep watch.
The goal of pharmacovigilance is to enhance patient safety and ensure that the benefits of medicines outweigh the risks. It plays a crucial role in the regulatory processes for ensuring the safe use of medicines throughout their lifecycle, from pre-market development to post-market surveillance.
Pharmacovigilance activities focus on identifying adverse drug reactions (ADRs), including unknown side effects, interactions with other drugs, misuse, and overuse of medicines. This system is essential for making informed decisions about the approval, withdrawal, or restriction of a pharmaceutical product.
Common terms used in Pharmacovigilance
1. Adverse Drug Reaction (ADR): A harmful, unintended, and noxious response to a drug at normal doses used for treatment, diagnosis, or prevention.
Example: A patient taking amoxicillin develops a severe allergic reaction (anaphylaxis), leading to swelling and difficulty breathing.
2. Adverse Event (AE): Any unintended medical occurrence after drug administration, regardless of its causal relationship with the drug.
Example: A patient on metformin experiences a headache, but further evaluation shows it may be due to dehydration, not the drug.
3. Serious Adverse Event (SAE): An AE that results in death, life-threatening conditions, hospitalization, disability, congenital defects, or medical intervention to prevent harm.
Example: A patient taking warfarin develops a major internal bleeding episode, requiring emergency hospitalization.
4. Signal Detection: The identification of a possible new risk associated with a drug, based on statistical analysis of pharmacovigilance data.
Example: Reports from multiple countries suggest that a new antidepressant may be linked to liver failure, triggering further investigation.
5. Causality Assessment: The process of determining whether a drug caused a reported ADR, using tools like the WHO-UMC scale or Naranjo Algorithm.
Example: A patient taking rifampicin develops liver toxicity, and an assessment shows a probable relationship based on timing and exclusion of other causes.
6. Pharmacovigilance System: A structured framework used by regulatory authorities and pharmaceutical companies to monitor, assess, and prevent ADRs.
Example: India’s Pharmacovigilance Programme (PvPI) collects and analyzes ADR reports through hospitals and healthcare professionals.
7. Risk Management Plan (RMP): A documented strategy designed to identify, assess, minimize, and communicate the risks associated with a drug.
Example: Due to the teratogenic risks of thalidomide, its RMP includes mandatory pregnancy testing and physician certification programs before prescribing.
8. Periodic Safety Update Report (PSUR): A comprehensive safety summary submitted periodically to regulatory agencies, containing updated risk-benefit analysis of a drug.
Example: A pharmaceutical company submits a PSUR for atorvastatin to report any new side effects observed in post-marketing surveillance.
9. Individual Case Safety Report (ICSR): A standardized report submitted to regulatory authorities detailing a single patient’s suspected ADR.
Example: A doctor reports a case of fatal myocarditis suspected to be linked to a COVID-19 vaccine, and the case is recorded as an ICSR.
10. MedDRA (Medical Dictionary for Regulatory Activities): A globally standardized medical terminology for coding and categorizing ADRs, symptoms, and diseases.
Example: In MedDRA, the term “rash” falls under the category “Skin and Subcutaneous Tissue Disorders.”
11. Disproportionality Analysis: A statistical method used to identify unexpected increases in ADR reporting rates for a specific drug.
Example: If sudden kidney failure is disproportionately higher in patients taking a new diabetes drug, regulators may issue a safety warning.
12. Risk-Benefit Assessment: The evaluation of whether a drug’s benefits outweigh its risks in real-world use.
Example: Clozapine carries a high risk of agranulocytosis but is still used in treatment-resistant schizophrenia due to its superior efficacy.
13. EudraVigilance: The official European database that collects and evaluates suspected ADR reports for medicines approved in Europe.
Example: ADR reports related to the AstraZeneca COVID-19 vaccine were closely monitored using EudraVigilance.
14. Spontaneous Reporting System (SRS): A voluntary reporting system where healthcare professionals and patients submit suspected ADRs.
Example: The FDA’s MedWatch system allows the public and professionals to report unexpected drug reactions.
15. Black Box Warning: The strongest safety warning issued by regulatory agencies for drugs with serious or life-threatening risks.
Example: Isotretinoin (Accutane) carries a black box warning due to its high risk of causing severe birth defects.
16. Post-Marketing Surveillance (PMS): The continuous monitoring of a drug’s safety after it has been approved and launched in the market.
Example: The withdrawal of Rofecoxib (Vioxx) in 2004 due to post-marketing data linking it to an increased risk of heart attacks and strokes.
17. Benefit-Risk Ratio: The comparison between a drug’s therapeutic benefits and its potential risks or adverse effects.
Example: Aspirin prevents heart attacks in high-risk patients, but it also increases the risk of gastrointestinal bleeding. The benefit-risk ratio determines its suitability for individual patients.
18. Suspected Unexpected Serious Adverse Reaction (SUSAR): A serious ADR that is unexpected, meaning it is not listed in the drug’s known safety profile.
Example: During a clinical trial, a patient taking a new antidepressant develops sudden blindness, an effect not previously reported.
19. Pharmacoepidemiology: The study of drug effects in large populations to assess safety and effectiveness.
Example: Researchers study millions of statin users to determine whether long-term statin use increases diabetes risk.
20. Good Pharmacovigilance Practices (GVP): A set of international standards for collecting, managing, and reporting safety data.
Example: The European Medicines Agency (EMA) mandates pharmaceutical companies to follow GVP guidelines for drug safety reporting.
Scope and Importance of Pharmacovigilance:
1. Ensuring Drug Safety: PV monitors and ensures that drugs remain safe for patients throughout their use.
2. Enhancing Public Health: By identifying ADRs, PV helps in reducing the harm caused by medications and enhances public trust in drug therapy.
3. Regulatory Compliance: Regulatory agencies, such as the FDA (U.S.), EMA (Europe), and CDSCO (India), rely on pharmacovigilance data to monitor the safety of drugs post-market.
4. Data Collection: PV collects data from various sources, including clinical trials, spontaneous reporting, literature, and patient databases, to assess risks associated with drug use.
5. Signal Detection and Risk Management: PV is responsible for detecting potential safety signals from adverse event reports and devising risk minimization strategies.
