How are drugs primarily excreted from the body?

Drugs are primarily excreted from the body through urine and feces because these routes effectively eliminate substances that are not needed or could be harmful to the body after their therapeutic effects have concluded.

The kidneys play a critical role in filtering blood, allowing soluble drugs and their metabolites to be removed from the body in urine. This process involves glomerular filtration, tubular secretion, and reabsorption, ensuring that waste products and excess substances are efficiently excreted.

Additionally, solid waste in the intestines can also contain unmetabolized drugs or their metabolites, which are eliminated through feces. This dual mechanism of excretion helps maintain the body’s homeostasis by removing drugs and preventing potential toxicity.

The roles of the liver, lungs, and metabolic pathways are significant in drug metabolism and clearance but do not encompass the primary means of excretion. The liver metabolizes drugs, making them easier for kidneys to excrete, while the lungs are involved mainly in the excretion of volatile substances. Metabolic pathways describe the alteration of drugs in the body but not the final process of elimination.