pharmacology

Pharmacology is the science of how drugs and living bodies affect each other. If a drug and a body are two dancers, pharmacology studies the whole dance: how the drug grabs hold of the body, what moves it triggers, how the body shuffles the drug around, and eventually how it shows the drug the door.

The field has two great halves. Pharmacodynamics asks what the drug does to the body: which target it binds, what effect that produces, and how the size of the dose relates to the size of the effect. Pharmacokinetics asks what the body does to the drug: how it is absorbed, distributed, metabolized, and excreted over time. Together these answer the two central questions of dosing: what happens, and how long.

Pharmacology sits between chemistry and medicine and overlaps with physiology, biochemistry, and toxicology. It is the basic science behind why a clinician chooses a particular drug, dose, and schedule. It does not by itself decide how to treat an individual patient, which is the work of therapeutics, but it supplies the mechanistic understanding that rational treatment depends on.