Pharmacology is the study of how drugs interact with living organisms. It sits at the intersection of chemistry, biology, and medicine, and it covers everything from how a drug binds to a receptor to how it is metabolized and excreted. The field is divided into two main branches: pharmacokinetics, which is what the body does to the drug, and pharmacodynamics, which is what the drug does to the body. Together, they explain how drugs work and how to use them safely.

Pharmacology is not the same as pharmacy. Pharmacy is the practice of preparing and dispensing medicines. Pharmacology is the science behind them. Pharmacologists work in universities, government labs, and the pharmaceutical industry. They study drug mechanisms, test new compounds, and investigate why some patients respond differently than others. The field has subdisciplines: neuropharmacology, cardiovascular pharmacology, clinical pharmacology, and toxicology, among others.

Branches of pharmacology:

• Pharmacokinetics. Absorption, distribution, metabolism, and excretion.
• Pharmacodynamics. Drug effects and mechanisms.
• Clinical pharmacology. Drug use in patients.
• Neuropharmacology. Drugs affecting the nervous system.
• Toxicology. Harmful effects of drugs and chemicals.

Pharmacology underpins evidence-based prescribing. Without it, dosing would be guesswork.