Outline the role of the liver in drug pharmacokinetics.
Most candidates structured their answer to this question well – they were aware of first pass metabolism and the effect of protein synthesis upon volume of distribution of drugs. Knowledge concerning Phase I and Phase II reactions was frequently inadequate. Many candidates were aware that these processes as well as inactivating or activating drugs resulted in increased water solubility to aid excretion via bile or urine. Few candidates discussed the significance of the large blood flow to the liver or the implications of high and low extraction ratios especially in relation to liver blood flow.
To include all the expected points, this answer could be structured by splitting the content into three major categories. These could be the clearance functions of the liver, first pass metabolism, mechanisms of hepatic metabolism, and the effects of liver disease.
The role of the liver in drug clearance:
The effect of the liver on first pass metabolism:
Biotransformation in the liver
Effects of changes in liver function
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