Pharmacology 2060A/B Lecture Notes - Lecture 4: Drug Metabolism, Liver Function Tests, Red Meat

• School: Western University
• Department: Pharmacology
• Course: Pharmacology 2060A/B
• Professor: Andrea Di Sebastiano

Document Summary

Biotransformation) is the enzyme-mediated alteration of a drug"s structure. Why do we need drug metabolism: protects us from a number of environmental toxins, as well as synthesize essential endogenous molecules, exogenous toxins that metabolism protects us from: red meat, alcohol, cigarettes, pills, some greens, caffeine. Even things like vegetables, that are healthy, would be toxic without the right enzymes: essential endogenous molecules synthesized by drug metabolizing enzymes: vitamin d, bile acid, cholesterol, steroids, bilirubin. !1: increase drug toxicity (non-toxic to toxic) 1st pass: po drugs (per os---> by mouth) may undergo signi cant metabolism before entering systemic circulation. May occur via: hepatocytes in liver (liver cells, intestinal enterocytes (ie. intestinal absorptive cells---> simple columnar epithelial cells found in the small intestine, stomach. Result is a decreased amount of parent drug that enters systemic circulation. Extraction ratio: the extraction ratio of a drug can be high or low depending on how much metabolism occurs on the 1st pass through the liver.