Which drug is given as an example of extensive tissue distribution and a long half-life due to high lipophilicity?

Which drug is given as an example of extensive tissue distribution and a long half-life due to high lipophilicity?

• A. Diazepam
• B. Acetaminophen
• C. Gentamicin
• D. Furosemide

Answer: (A)

High lipophilicity lets a drug cross membranes easily and spread into many tissues, producing a large volume of distribution and a long elimination half-life because the compound is stored in fat and other tissues and released slowly back into the bloodstream. Diazepam is a classic example: it is highly lipophilic, distributes extensively into tissues, and its active metabolites also linger, giving a prolonged duration of action. In contrast, acetaminophen is relatively hydrophilic and remains largely in the bloodstream and extracellular fluid with a short half-life; gentamicin is polar and concentrates in extracellular fluid with limited tissue penetration and a shorter half-life; furosemide is not as lipophilic and, despite protein binding, does not show the same extensive tissue distribution or very long half-life.

High lipophilicity lets a drug cross membranes easily and spread into many tissues, producing a large volume of distribution and a long elimination half-life because the compound is stored in fat and other tissues and released slowly back into the bloodstream. Diazepam is a classic example: it is highly lipophilic, distributes extensively into tissues, and its active metabolites also linger, giving a prolonged duration of action. In contrast, acetaminophen is relatively hydrophilic and remains largely in the bloodstream and extracellular fluid with a short half-life; gentamicin is polar and concentrates in extracellular fluid with limited tissue penetration and a shorter half-life; furosemide is not as lipophilic and, despite protein binding, does not show the same extensive tissue distribution or very long half-life.