卫生部规划教材《药理学》第七版书中写到，克拉霉素口服吸收迅速完全，但其首过消除明显，生物利用度仅有55%。如何解释二者之间的矛盾？
国外的说明书如下：
Clarithromycin is rapidly absorbed from the gastrointestinal tract after oral administration. The absolute bioavailability of 250 mg clarithromycin tablets was approximately 50%. For a single 500 mg dose of clarithromycin, food slightly delays the onset of clarithromycin absorption, increasing the peak time from approximately 2 to 2.5 hours. Food also increases the clarithromycin peak plasma concentration by about 24%, but does not affect the extent of clarithromycin bioavailability. Food does not affect the onset of formation of the antimicrobially active metabolite, 14-OH clarithromycin or its peak plasma concentration but does slightly decrease the extent of metabolite formation, indicated by an 11% decrease in area under the plasma concentration-time curve (AUC). Therefore, clarithromycin tablets may be given without regard to food.
不矛盾，首先应准确理解生物利用度的概念，计算生物利用度时要考虑首过消除等药量减少的因素之后才能算！
我的意思是说，克拉霉素口服吸收迅速完全与其生物利用度仅有55%，二者之间是否矛盾？
国外的说明书如下：
Clarithromycin is rapidly absorbed from the gastrointestinal tract after oral administration. The absolute bioavailability of 250 mg clarithromycin tablets was approximately 50%. For a single 500 mg dose of clarithromycin, food slightly delays the onset of clarithromycin absorption, increasing the peak time from approximately 2 to 2.5 hours. Food also increases the clarithromycin peak plasma concentration by about 24%, but does not affect the extent of clarithromycin bioavailability. Food does not affect the onset of formation of the antimicrobially active metabolite, 14-OH clarithromycin or its peak plasma concentration but does slightly decrease the extent of metabolite formation, indicated by an 11% decrease in area under the plasma concentration-time curve (AUC). Therefore, clarithromycin tablets may be given without regard to food.
不矛盾，首先应准确理解生物利用度的概念，计算生物利用度时要考虑首过消除等药量减少的因素之后才能算！
我的意思是说，克拉霉素口服吸收迅速完全与其生物利用度仅有55%，二者之间是否矛盾？