Pharmacology is the study of drugs and their effects on living organisms. It is traditionally divided into two complementary branches. Pharmacokinetics describes what the body does to a drug and is summarized by the acronym ADME: Absorption, Distribution, Metabolism, and Excretion. These four processes together determine how much active drug reaches its site of action and how long it remains there. Pharmacodynamics, in contrast, describes what the drug does to the body, including its mechanism of action, the relationship between dose and response, and the resulting therapeutic and adverse effects. Most drugs produce their effects by binding to specific molecular targets, most commonly receptors, enzymes, ion channels, or transport proteins, and this binding is the basis of a drug's mechanism of action.
Recognizing drug names by their suffixes is a useful practical skill in pharmacology because the ending of a generic name usually reveals its class. For example, suffixes such as -olol denote beta-blockers, -pril indicates ACE inhibitors, -sartan indicates angiotensin receptor blockers, -statin indicates HMG-CoA reductase inhibitors, -prazole indicates proton pump inhibitors, -dipine indicates calcium channel blockers, -cillin indicates penicillins, and -azole indicates antifungal azoles. In the United States, the Food and Drug Administration oversees the development, approval, manufacturing, and marketing of drugs, ensuring that marketed medications have demonstrated both safety and efficacy through rigorous preclinical and clinical testing.