bioavailability
The proportion of an administered drug that reaches systemic circulation and is available for therapeutic action.
Full Definition
Bioavailability measures the extent and rate at which a medication becomes available to produce its therapeutic effect after administration. In psychopharmacology, bioavailability is influenced by factors such as formulation, route of administration, first-pass metabolism, and individual patient characteristics. This concept is crucial when switching between different formulations of the same medication (such as immediate-release versus extended-release) or between brand and generic versions. Understanding bioavailability helps clinicians make appropriate dose adjustments and explains why some patients may respond differently to seemingly equivalent medications.
Usage
Usage note: Refers specifically to drug absorption and availability, not biological activity or efficacy.
In Context
- "The extended-release formulation has different bioavailability characteristics compared to immediate-release tablets." — Pharmacokinetic report
- "Food may affect the bioavailability of this psychiatric medication." — Prescribing information