Glossary terms - F first pass effect First pass effect is the biotransformation and/or excretion of a drug by intestinal and hepatic mechanisms (including biliary) following absorption of the drug from the gastrointestinal tract, before the drug gains access to the systemic circulation. first-order kinetics Used to refer to when a constant proportion of drug in a biological system is eliminated per unit of time. This article was published on 2025-01-28
