Excretion: Finally, the drug and its metabolites are removed from the body. The kidneys are the primary organs for excretion via urine, though drugs can also be cleared through bile, sweat, or breath. Pharmacodynamics: What the Drug Does to the Body
Pharmacokinetics describes the movement of a drug into, through, and out of the body. This process is typically divided into four stages, often referred to by the acronym ADME: Basic Pharmacokinetics and Pharmacodynamics: An...
Pharmacology is built on two fundamental pillars: pharmacokinetics (PK) and pharmacodynamics (PD). Understanding these concepts is essential for determining how drugs move through the body and how they exert their therapeutic effects. While they are distinct fields of study, they are deeply interrelated and together dictate the clinical outcome of any drug therapy. Pharmacokinetics: What the Body Does to the Drug Excretion: Finally, the drug and its metabolites are
Metabolism: The body, primarily the liver, chemically alters the drug to make it easier to excrete. This often involves transforming active drugs into inactive metabolites, though some "prodrugs" are designed to become active only after metabolism. This process is typically divided into four stages,
Distribution: Once in the blood, the drug is carried to various tissues and organs. Distribution depends on blood flow, the drug’s ability to cross cell membranes (like the blood-brain barrier), and its tendency to bind to plasma proteins.