Beyond receptors, drugs may also target enzymes (such as NSAIDs inhibiting cyclooxygenase), transporters, or ion channels directly. Agonists, Antagonists, and Affinity
: Control the flow of ions across membranes.
: Refers to how tightly a drug binds to its receptor, measured by the dissociation constant ( Kdcap K sub d ). A smaller Kdcap K sub d pharmacodynamic
Central to pharmacodynamics is the , which quantifies how the intensity of an effect changes with varying drug concentrations. This is typically visualized using a concentration-response curve. Key metrics include: Emaxcap E sub m a x end-sub : The maximal effect a drug can produce regardless of dose. EC50cap E cap C sub 50
There are four major types of receptors that facilitate these signals: Beyond receptors, drugs may also target enzymes (such
indicates higher affinity, meaning lower doses are often required for effect. The Dose-Response Relationship
: Drugs that bind to and activate a receptor, mimicking natural signaling molecules. A smaller Kdcap K sub d Central to
: Bind to lipid-soluble drugs like steroids within the cell.