Drug Excretion

Capitulo de Libro

Summary *

Drug excretion involves processes responsible for physically removing a drug from the body, either unchanged or in the form of biotransformation products. The main routes for drug excretion are the urine and bile. Whereas unchanged polar compounds are excreted efficiently, hydrophobic drugs require previous metabolism (Phase I and/or Phase II biotransformation reactions) to increase their excretion efficiency. Depending on the chemical properties of the drugs, they may be reabsorbed from the intestine or the tubular lumen. Drugs excreted in the bile and subjected to intestinal reabsorption can enter enterohepatic recycling, sometimes with hepatic conjugation and intestinal deconjugation. In some cases, drug molecules can be excreted through the lungs (volatile drugs) and sweat. Whereas they are not “intended” excretion routes, drug molecules may appear in milk, tears, semen, hair, and saliva. Information provided by the agent in SIGEVA