Describe how enzyme induction affects clearance over time and what is a typical clinical implication?

• A. Induction decreases clearance over time; dose reduction may be needed
• B. Induction increases clearance over time; dosing may need to be increased or intervals shortened after induction
• C. Induction has no effect on clearance
• D. Induction causes clearance to become unpredictable

Answer: (D)

Enzyme induction increases the amount of drug-metabolizing enzymes in the liver, so the body's capacity to clear a drug grows as induction progresses. Over time, this enhanced metabolic activity speeds up drug clearance, which can lower drug exposure unless dosing is adjusted. Clinically, after induction, you may need to raise the dose or shorten the dosing interval to maintain the same effect. The onset of induction typically takes several days to weeks and, if the inducer is stopped, clearance tends to return toward baseline over a similar timescale, meaning dose adjustments may be needed during both induction and de-induction phases.