Administration of an enzyme inducer will significantly increase the first-pass effect, while the rate of absorption and elimination will not significantly change. Thus, there will be a substantial decrease in the peak concentration of the parent drug and a substantial increase in the peal concentration of the metabolite(s) formed during first-pass. Since peak concentration is related to intensity of pharmacologic effect, the biggest impact of an enzyme inducer on an orally administered drug subject to first-pass metabolism will be on the intensity of pharmacologic effect.

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