The World Health Organisation defines pharmacovigilance as a science with the aim of detecting, assessing, understanding and preventing adverse effects caused by or related to medical drugs. This article helps you understand the definitions of key events within the science with reference to the ICH guidelines for industry professionals and physicians widely used throughout Europe today.
What Are Adverse Events & Adverse Reactions?
The ICH guidelines characterise Adverse Events as medical occurrences of an adverse nature – in layman’s terms, something which isn’t medically desirable that occurs as a result of taking the medicine. They occur when a patient (or sometimes a healthy volunteer participating in a clinical trial) has had a medicine administered and include laboratory findings outside normal accepted values or ranges of values. It could be that there is no known causal relationship between the medicine and the Adverse Event to date. It could be that symptoms or diseases are temporarily associated with the medicinal product without a precedent.
In the testing stages before a product is allowed to go on general sale, Adverse Events are unwanted medical responses to a drug which were not described in the literature made available by the team responsible for the testing. Later in the product life cycle, once a drug has entered the market, they include unwanted medical events which take place at routine dosages that doctors would prescribe to treat disease or modify physical function. Some contemporary definitions also now include unwanted effects (or potential effects) that occur at dosages and/or when the drug is administered for a use which is not routinely recommended.
What Are Serious Adverse Events (SAEs)?
These are events which pose a serious threat to life or quality of life for patients (or healthy trial participants):
- A fatality
- A threat to life
- The patient must be hospitalised or have an existing hospital stay extended
- A significant, enduring disability or compromise in patient function
- Congenital anomalies or birth defects
The definition also includes any event for which medical intervention is needed to protect the patient (or trial participant) from any of the events on the above list An event is also classed as serious if it jeopardises the patient in some other way; and within the EU, if it involves suspected transmission of infection.
What Is A Suspected Adverse Drug Reaction?
This term encompasses events where the reasonable possibility exists of a connection between the event and taking the drug. The majority will be treated as suspected not confirmed as additional evidence will be required at the point of discovery. This could involve “dechallenge and rechallenge” where ethically possible.
What are Suspected Unexpected Serious Adverse Reactions (SUSARs) and Expected Drug Reactions?
During the pre-marketing phase, a Suspected Unexpected Serious Adverse Reaction constitutes any serious suspected adverse reaction presenting inconsistencies with the information the investigator has previously made available. During the post-marketing phase, unexpected reactions constitute those which present inconsistencies with the listed adverse reactions on the standard product information (the “labelling”, Summary of Product Characteristics or package inserts). In some post-marketing phase it is still possible for the investigator’s pre-marketing information to be the reference document for products placed on the market.
Pharmacovigilance aims to protect patients and the public wherever possible, disseminating information and knowledge among the appropriate professional communities and among patients to minimise risk. Please note this information is intended as a brief introduction only and does not constitute any form of drug safety, legal or other professional advice.
Source by Jon Barton