Pharmacovigilance (PV) protects public health by influencing post-marketing decision-making. This entails monitoring, assessing, and preventing adverse effects or drug-related problems of pharmaceutical products once the medicine or biological product has been marketed.

Pre-approval clinical trials only provide partial information regarding drug efficacy and safety, as the drug is studied under controlled conditions and often with few participants. To assess medication-related problems that cannot be detected in controlled pre-marketing trials, rare, long-term, and real-world adverse events must be monitored as part of post-market drug safety surveillance through pharmacovigilance systems. 

This article aims to identify and discuss the significance of pharmacovigilance in clinical settings, its types, regulations, and the new technologies developed to further the surveillance of drug safety once marketed.

Introduction

The process of going from bench to pharmacy shelf is neither short nor easy. Medications undergo rigorous clinical testing, but even with this testing before marketing, no matter how rigorous, pre-marketing trials can never predict every possible adverse event or combination of events.

The important role of pharmacovigilance, both as a science and as a set of activities related to the detection, assessment, understanding, and prevention of adverse effects or any other drug-related problems, becomes essential in this area of drug development.

Due to the increased use of drugs at both individual and global levels and the growing pharmaceutical market, the influence of pharmacovigilance in clinical research has become even more substantial. This role allows the benefit-risk profile of medicinal products to be continually evaluated to protect patients and inform clinicians, regulators, and pharmaceutical companies.

Limitations of Pre-Marketing Trials
Clinical trials are conducted under controlled conditions, which normally include rigorous inclusion/exclusion criteria. 

Therefore, clinical trials often cannot:

• Represent the same patient populations, such as people over 65 years, pregnant women, or people with comorbidities

• Detect rare or possibly long-term side effects from drug use

• Predict drug-drug or drug-food interactions once in clinical use

Because of these reasons, the safety of a drug often cannot be fully established until it is marketed and available to a larger and more diverse patient population.

Capturing Real-World Data (RWD) and Safety Signals

Pharmacovigilance and post-marketing data collection capture real-world evidence to allow the detection of:

• Adverse Drug Reactions (ADRs): Unexpected harmful responses to medications

• Medication Errors: Adverse events resulting from issues with prescribing, dispensing, or administration of medication

• Drug Interactions: Adverse events resulting from the concurrent use of multiple therapy regimens

• Off-Label Use: Effects from administering medications outside the approved indications

The ability to capture these events helps detect early signals, take action to prevent future occurrences, mitigate risks, and minimize harm.

Pharmacovigilance Methods and Tools
Some pharmacovigilance systems use both passive and active methods.

• Spontaneous Reporting Systems (SRS)
Healthcare professionals and patients can report suspected ADRs to regulatory authorities or manufacturers. Regulatory bodies and the WHO manage databases and reports like EudraVigilance (EU), FAERS (US FDA), and VigiBase (WHO).

• Active Surveillance
This method engages more actively with data from various sources like patient registries, electronic health records (EHRs), or cohort event monitoring and reporting. The FDA Sentinel Initiative is an example of a highly active surveillance model using RWD.

• Signal Detection and Risk Management
Statistical methods and algorithms identify trends or clusters of ADRs. These identified signals are assessed for causality, seriousness, and frequency. Risk Management Plans (RMPs) are then established to manage or reduce potential harm.

Regulation and Global Harmonization
The pharmacovigilance industry operates under both national and international oversight to ensure harmonized and standardized practices.

• International Council for Harmonisation - Pharmacovigilance E2E Guidelines: Outlines pharmacovigilance planning within the clinical context

• European Medicines Agency - Good Pharmacovigilance Practices (GVP): Defines general responsibilities of marketing authorization holders across Europe

• US Food and Drug Administration - Post-Marketing Requirements (PMRs): Specifies requirements to continue safety evaluation before, during, and after drug approva

Regulatory authorities collaborate internationally to monitor newly approved and marketed drugs via platforms like the International Coalition of Medicines Regulatory Authorities (ICMRA) and Uppsala Monitoring Centre (UMC).

Challenges in Pharmacovigilance

The pharmacovigilance landscape continues to evolve and presents several challenges:

• Under-reporting of ADRs: More common in developing countries or among healthcare providers with limited awareness

• Quality of Data and Identification of Data Sources: This can be problematic when using multiple, non-primary sources

• Causality Assessment: Determining if an ADR is genuinely drug-related is especially challenging in poly medicated patients

• Speed of Drug Approvals: Accelerated approval pathways may reduce the availability of long-term safety data at launch.

Technology and Artificial Intelligence 

Emerging technology is rapidly reshaping pharmacovigilance. Artificial Intelligence (AI) and Natural Language Processing (NLP) are now employed in areas such as signal detection, literature screening, and case triage.

Blockchain technology can enhance trust and integrity in safety databases. Rich data collection approaches (e.g., mobile apps and digital platforms) enable direct patient engagement, allowing patients to report ADRs directly to pharmaceutical companies. The increased volume and diversity of data sources positively influence the future of pharmacovigilance.

Digital pharmacovigilance enables robust data analysis and timely action, especially when integrated with EHRs and real-time patient monitoring.

Conclusion

In the continuum of clinical research, pharmacovigilance stands out as one of the most important pillars, extending the responsibility of drug safety beyond license approvals. Once a drug reaches the real world, post-marketing surveillance ensures that potential risks are identified and managed promptly. With advances in data science, regulatory harmonization, and public engagement, pharmacovigilance is shifting from passive monitoring to a more proactive and prescriptive discipline that supports one of the most ethical practices in modern medicine: "First, not harm."