Which combination correctly lists common routes of drug excretion?

• A. Kidneys, liver (bile), feces, lungs, saliva
• B. Kidneys only
• C. Feces and urine only
• D. Lungs and skin only

Answer: (A)

A drug is eliminated from the body through several common routes, not just one. The main pathways include renal excretion into urine, hepatic (biliary) excretion into bile and then feces, exhalation via the lungs for volatile substances, and even small amounts can appear in saliva or other secretions. The combination that lists kidneys, liver (bile), feces, lungs, and saliva covers these primary routes, reflecting both the dominant renal route and the important alternative pathways the body uses to remove drugs. Other options are incomplete because they omit one or more of these key excretion pathways, such as excluding biliary/fecal excretion, lung excretion, or minor routes like saliva.