Which statement best explains prolonged fentanyl elimination in elderly patients?

Which statement best explains prolonged fentanyl elimination in elderly patients?

• A. Increased hepatic clearance
• B. Reduced hepatic clearance
• C. Increased enzyme activity
• D. Increased hepatic blood flow

Answer: (B)

Fentanyl clearance in the elderly is slowed mainly because liver perfusion declines with age. Fentanyl is a high-extraction, lipophilic drug whose hepatic clearance is largely determined by how much blood flows through the liver. When hepatic blood flow drops in older adults, less drug reaches the liver per unit time, so overall clearance decreases and the drug stays in the body longer, prolonging elimination. While intrinsic enzyme activity may also decline with age, the dominant factor for fentanyl is reduced hepatic perfusion. Increased hepatic blood flow or increased enzyme activity would speed clearance, not slow it.

Fentanyl clearance in the elderly is slowed mainly because liver perfusion declines with age. Fentanyl is a high-extraction, lipophilic drug whose hepatic clearance is largely determined by how much blood flows through the liver. When hepatic blood flow drops in older adults, less drug reaches the liver per unit time, so overall clearance decreases and the drug stays in the body longer, prolonging elimination. While intrinsic enzyme activity may also decline with age, the dominant factor for fentanyl is reduced hepatic perfusion. Increased hepatic blood flow or increased enzyme activity would speed clearance, not slow it.