About the classification and causality of adverse drug effects

Abstract

In the fifteenth century, Paracelsus stressed that all substances were potentially deleterious. The only difference between a poison and a remedy he considered to be the dose in which it was used. Many centuries passed until the modern development of pharmacology, and this concept is currently applicable to those drugs that cause reactions or adverse effects in a dose-dependent manner, both with acute and chronic exposure, due to cumulative effect.