Pharm Liver drugs

Question 1

Match the following actions together

A) prodrug, liver inactivation
B) bio-inactivation, decreased polarity
C) Bile excretion;polar drug
D) toxification; no liver interaction

Answer 1

C) for a drug to be excreted in bile it must be soluble or made more polar.

Question 2

Phase 1 drug metabolism involves what enzymes? Which drugs are inducers and which are inhibitors?

Answer 2

Cytochrome- P (CYP)-450 enzymes

Inducers: Rifampin, Phenytoin, Carbamazepine, phenobarbital

Inhibitors: -conazoles, HIV protease inhibitors, erythro and clarithromycin.

Question 3

What is the first pass effect and how does this effect drug pharmacology?

Answer 3

This process describes how much drug is inactivated as it passes through the liver for the first time, before reaching systemic circulation. Non oral medicines delivery avoids this first pass effect, and thus alters the bio-availability of drugs.

Question 4

What are the factors that play into the degree of the first pass effect on a given drug?

Answer 4

Absorption in the gut, the efflux transporter p-glycoprotein, and the first pass in the liver after the drug is taken up by the portal system.

Question 5

How does cirrhosis impair drug metabolism and the first pass effect?

Answer 5

1 shunts blood through collateral circulation (decrease first pass effect)
2 decrease in drug binding proteins (total drug concentration will be lower, but unbound concentrations will be the same)
3 abnormal distribution (ascities, edema)
4 altered pharmacodynamics
5 hepato-renal syndrome
6 altered metabolism ad elimination