Which group has less plasma protein binding of drugs and inefficient hepatic metabolism compared to adults?

Which group has less plasma protein binding of drugs and inefficient hepatic metabolism compared to adults?

• A. Young
• B. Old
• C. Both young and old
• D. Neither

Answer: (A)

Young patients, especially neonates and infants, have less plasma protein binding and immature hepatic metabolism compared with adults. Albumin levels and binding capacity are lower, and other binding proteins may be reduced or variably available, so a larger fraction of many drugs remains unbound and pharmacologically active. At the same time, liver enzymes responsible for drug metabolism, particularly the cytochrome P450 system, are not fully developed, and hepatic blood flow relative to body size is limited. This combination leads to slower drug clearance and prolonged effects. While elderly patients can also show reduced metabolism, the simultaneous reduction in both plasma protein binding and hepatic metabolic capacity is most characteristic of the young.

Young patients, especially neonates and infants, have less plasma protein binding and immature hepatic metabolism compared with adults. Albumin levels and binding capacity are lower, and other binding proteins may be reduced or variably available, so a larger fraction of many drugs remains unbound and pharmacologically active. At the same time, liver enzymes responsible for drug metabolism, particularly the cytochrome P450 system, are not fully developed, and hepatic blood flow relative to body size is limited. This combination leads to slower drug clearance and prolonged effects. While elderly patients can also show reduced metabolism, the simultaneous reduction in both plasma protein binding and hepatic metabolic capacity is most characteristic of the young.