MEDICAL ANIMATION TRANSCRIPT: Many factors influence the therapeutic efficacy of a drug, including pharmacokinetics, a quantifiable measure of how the body affects the drug. And pharmacodynamics, how the drug affects the body. Pharmacokinetics is a multi-step process that includes absorption or the movement of the drug into the bloodstream. Distribution, or the movement of the drug through the blood and various tissues of the body such as brain tissue, fat, and muscle. Metabolism, or the chemical alteration of the drug by the body. And excretion, or the elimination of the drug by the body. This four-step process is referred to by the acronym ADME. During distribution of certain drugs, proteins present in the bloodstream such as serum albumin bind the drug and render it inaccessible to its target. Effective dose concentration is a measure of unbound drug present in the bloodstream. Thus, pharmacokinetics determines factors within the body that dictate when and how much unbound drug reac...