Bioavailability

Topic: Pharmacology

The fraction of a dose that reaches the systemic circulation unchanged. An IV drug has 100% bioavailability; oral drugs usually have less, because they must be absorbed and many are partly broken down by the liver before reaching the circulation (the first-pass effect). That is why oral and IV doses of the same drug can differ, and why sublingual, transdermal or rectal routes can bypass part of the first pass. Food, other drugs, and gut or liver disease change bioavailability, so give drugs as directed in relation to meals and never switch routes without an order.

Also known as:

First-pass effect, First-pass metabolism

In Turkish:

Biyoyararlanım