If a patient has reduced albumin levels, what is the expected effect on the free fraction of a highly protein-bound drug?

If a patient has reduced albumin levels, what is the expected effect on the free fraction of a highly protein-bound drug?

• A. Decrease in the free fraction of the drug
• B. Increase in the free fraction of the drug
• C. No change in the free fraction
• D. Increase in total body concentration

Answer: (B)

High protein-bound drugs rely on albumin to hold most of the drug in the bound state. The unbound portion is the active form that distributes into tissues and is cleared. When albumin levels drop, there are fewer binding sites, so a larger share of the drug remains unbound. This increases the free fraction. The rise in unbound drug can enhance effects and toxicity and can also alter distribution and clearance, sometimes lowering the total drug level as more is cleared.

High protein-bound drugs rely on albumin to hold most of the drug in the bound state. The unbound portion is the active form that distributes into tissues and is cleared. When albumin levels drop, there are fewer binding sites, so a larger share of the drug remains unbound. This increases the free fraction. The rise in unbound drug can enhance effects and toxicity and can also alter distribution and clearance, sometimes lowering the total drug level as more is cleared.