Tag: Free drug concentration

Over half of the 100 most prescribed drugs in the United States are more than 90% plasma protein bound [1.5.3]. Understanding **what drugs are plasma bound** is crucial for grasping their efficacy, potential for interactions, and overall effect on the body [1.5.2, 1.3.1].

Over half of the 222 drugs compiled in one study were found to be highly plasma protein-bound, profoundly affecting their distribution and action within the body. The answer to the question, "Is plasma affected by drugs?" is a definitive yes, as this binding is a fundamental component of pharmacokinetics.

For many common medications, over 90% of the drug molecules in the bloodstream are bound to plasma proteins like albumin. The small, remaining percentage is **what is an unbound drug**—the freely circulating, pharmacologically active portion that determines a medication's therapeutic effect and risk of side effects.