Medical Terms & Explanations 101 x Adverse Drug Reactions

Definition

According to the definition of the European Medicines Agency (EMA), adverse drug reactions (ADRs) are “a response to a medicinal product which is noxious and unintended.”^[1] These side effects can be caused by any pharmacologically active drug, even when it is used as intended.

Side effects resulting from (intentional or unintentional) excessive use of medicines, on the other hand, are referred to as toxicity.

When healthcare professionals prescribe medicines, a risk-benefit assessment is required, since all medicines can theoretically cause ADRs.^[2] For this reason, patients must be aware of the risks before use and be informed accordingly.

‍

How can adverse drug reactions occur?

ADRs often result from the low selectivity of active substances. Selectivity generally describes how many different structures or tissues an active substance binds to.^[3] The higher the selectivity, the fewer structures are bound that could potentially cause ADRs.

Another reason, which follows from this, is the diversity of patient groups. The studies that medicines have to undergo before their marketing authorization often have strict inclusion criteria, which exclude relevant target groups. In very old or pregnant people, for example, these medicines can then cause ADRs in the real world.

‍

Where can I find this information?

This information can be found in the package leaflet, the summary of product characteristics, or on web platforms such as EudraVigilance or ImpactMonitor. The information on adverse reactions comes from the studies mentioned above, from routine practice data collection, or from spontaneous reports, which count as real-world evidence.

‍

Why reporting adverse drug reactions is important

Doctors, pharmacists, pharmaceutical manufacturers, and patients are therefore all called upon to help detect adverse drug reactions.^[4] This leads to a lasting improvement in patient safety and drug safety. Reporting ADRs is absolutely essential, especially for newer medicines that, for example, have only been granted conditional marketing authorization. Incidentally, such reports can be recorded easily and securely via the ImpactMonitor.

‍

Sources:

^[1] European Medicines Agency. Adverse drug reaction. https://www.ema.europa.eu/en/glossary/adverse-drug-reaction Last accessed: 15.03.2021

^[2] Smith Marsh E. Daphne. 2018. PharmD. BC-ADM. CDE. College of Pharmacy. University of Illinois at Chicago. https://www.msdmanuals.com/de-de/heim/medikamente/unerwünschte-arzneimittelwirkungen/das-nutzen-risiko-verhältnis-von-medikamenten Last accessed: 15.03.2021

^[3]Urban JD et al. Functional selectivity and classical concepts of quantitative pharmacology. J Pharmacol Exp Ther. 2007. 320(1) p. 1-13.

^[4] Barry, A. R., Koshman, S. L., & Pearson, G. J. (2014). Adverse drug reactions: The importance of maintaining pharmacovigilance. Canadian pharmacists journal : CPJ = Revue des pharmaciens du Canada : RPC, 147(4), 233–238. misunderstanding randomized controlled trials. Vol 210. p.  2-21.