Which fate describes a free drug that becomes sequestered in other tissues with no immediate effect?

• A. Exerts Effect at Site of Action
• B. Sequestered in Other Tissues
• C. Metabolized
• D. Eliminated Directly

Answer: (B)

Free drug that becomes sequestered in other tissues highlights how distribution into non-target compartments can remove the active fraction from the site of action. When a drug is free, it can interact with receptors, but if it partitions into tissues or binds strongly and becomes trapped, the immediately available concentration at the action site drops. That lack of free drug at the site means no immediate effect is observed, even though the drug still exists in the body and can act later if it redistributes back. This tissue sequestration can also create a reservoir that may release the drug over time, potentially causing delayed or prolonged effects. The other fates describe different processes: acting at the site of action requires the drug to be freely available there; metabolism involves chemical change to metabolites; and direct elimination refers to removal from the body, not storage in tissues.