Pharmacodynamics concerns the biological activity and clinical effects of a drug—the drug action after distribution (pharmacokinetics) of the active agent to the therapeutic site. Included within the area of pharmacodynamics are the tissue receptor for the drug and the intracellular changes initiated by binding of the active drug with the receptor. The pharmacodynamic action of a drug is often described using the receptor for that drug; for example, a drug may be categorized as an α-adrenergic agonist or a β-adrenergic antagonist.
Excerpted from BCSC 2020-2021 series: Section 2 - Fundamentals and Principles of Ophthalmology. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.