Public Health · Short notes

Pharmacovigilance: Short Notes & Cheat Sheet

Definition and methods of pharmacovigilance, signals, individual case reports, the WHO programme, DRAP's role and famous drug withdrawals.

Short notes

Read these before you attempt the topic's MCQs.

Each report adds to the evidence; action follows only when a signal is confirmed.

WHO defines pharmacovigilance as the science and activities relating to the detection, assessment, understanding and prevention of adverse effects or any other drug-related problem.
It exists because clinical trials are too small and too short to reveal rare or delayed reactions.
The WHO Programme for International Drug Monitoring began in 1968 after the thalidomide disaster. Its Uppsala Monitoring Centre in Sweden runs the global database, VigiBase.
In Pakistan, DRAP runs the national pharmacovigilance system under the Pharmacovigilance Rules 2022; healthcare professionals, patients and companies can report suspected reactions.

Spontaneous reporting is the most widely used method and is good at detecting rare, new reactions. Its main weakness is under-reporting.
Other methods: intensive (cohort event) monitoring, prescription event monitoring, active surveillance, registries and case-control studies.
A valid individual case safety report needs four minimum elements: an identifiable patient, an identifiable reporter, a suspected drug and an adverse event.
A signal is information suggesting a new possible causal link between a drug and an event, usually needing more than one report to confirm.
Companies submit periodic safety reports (PSUR/PBRER) and follow risk management plans.
Related fields: materiovigilance (devices), haemovigilance (blood) and AEFI surveillance (vaccines).

Thalidomide (1961): limb defects (phocomelia) in babies.
Rofecoxib (2004): heart attacks and strokes.
Cerivastatin: rhabdomyolysis. Terfenadine: QT prolongation and arrhythmias. Troglitazone: liver failure.
Ranitidine (2020): contamination with the probable carcinogen NDMA.

High-yield facts in one place. Cover the right-hand column and test yourself.

Item	Detail
WHO programme started	1968 (after thalidomide)
Global centre	Uppsala Monitoring Centre, Sweden
Global database	VigiBase
Most common method	Spontaneous reporting
Main weakness	Under-reporting
Minimum report elements	Patient, reporter, drug, event
Pakistan	DRAP national pharmacovigilance centre

4 to report: Patient, Reporter, Drug, Event: The four minimum elements of a valid case report.

A single report is rarely enough to confirm a signal.
Spontaneous reporting cannot measure how often a reaction occurs, because the number of exposed patients is unknown.
Pharmacovigilance covers medication errors and lack of effect, not just adverse reactions.
The Uppsala Monitoring Centre is in Sweden, not Geneva.

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