Which type of tolerance involves the liver adjusting enzyme production to metabolize the drug more efficiently?

Which type of tolerance involves the liver adjusting enzyme production to metabolize the drug more efficiently?

• A. Pharmacodynamic tolerance
• B. Metabolic tolerance
• C. Behavioral tolerance
• D. Tolerance

Answer: (D)

Metabolic tolerance develops when the liver increases the production of drug‑processing enzymes, speeding up metabolism so the drug is cleared more quickly. With more enzymes in play, the same dose results in lower active drug levels and a diminished effect unless the dose is raised. This is a pharmacokinetic change—the body’s processing of the drug is altered, not the drug’s action at its target. This differs from pharmacodynamic tolerance, where the target tissues become less responsive due to receptor changes or signaling adaptations; from behavioral tolerance, where cognitive or motor adaptations help a person function despite the drug; and from the generic term tolerance, which doesn’t specify the mechanism. So the scenario described aligns with metabolic tolerance.

Metabolic tolerance develops when the liver increases the production of drug‑processing enzymes, speeding up metabolism so the drug is cleared more quickly. With more enzymes in play, the same dose results in lower active drug levels and a diminished effect unless the dose is raised. This is a pharmacokinetic change—the body’s processing of the drug is altered, not the drug’s action at its target.

This differs from pharmacodynamic tolerance, where the target tissues become less responsive due to receptor changes or signaling adaptations; from behavioral tolerance, where cognitive or motor adaptations help a person function despite the drug; and from the generic term tolerance, which doesn’t specify the mechanism.

So the scenario described aligns with metabolic tolerance.