Farmacodinámica

Farmacodinámica is the branch of pharmacology that studies the biochemical and physiological effects of drugs and their mechanisms of action within the body. It describes what a drug does to the body, in contrast to pharmacokinetics, which describes what the body does to a drug. Understanding pharmacodynamics is crucial for determining the appropriate dosage and frequency of a drug to achieve a desired therapeutic effect while minimizing adverse reactions.

The core of pharmacodynamics lies in the interaction between a drug molecule and its target site in the body, typically a receptor. Drugs can act as agonists, binding to a receptor and activating it to produce a biological response, or as antagonists, binding to a receptor without activating it, thereby blocking the action of agonists. The affinity of a drug for its receptor refers to the strength of this binding, while efficacy describes the ability of the drug to produce a response once bound.

These interactions lead to a cascade of events that ultimately alter physiological processes. For example, a drug might inhibit an enzyme, block a channel, or modulate the activity of signaling molecules. The intensity and duration of the drug's effect are influenced by factors such as the concentration of the drug at the target site and the number of receptors available. Dose-response relationships are fundamental to pharmacodynamics, illustrating how the magnitude of a drug's effect changes with its concentration.