Drug Metabolism Flashcards
1
Q
Define Phase I reactions
A
Hydroxylation X-OH
Epoxidation
Dealkylation R-NH-CH3→ R-NH2
N-oxidation and hydroxylation R-NH2→ R-NH-OH
Oxidative deamination and desulfuration R2C=S → R2C=O
S-oxidation R2S → R2S=O
Oxidative dehalogenation CH-CL3→ CCl=O
2
Q
What are the other enzymes involved in phase I reactions?
A
FAD monooxygenase Monoamine and diamine oxidase Alcohol dehydrogenase Aldehyde dehydrogenase Xanthine oxidase
3
Q
What are the 5 major phase II reactions and what are their co-factors?
A
1) Glucuronidation (UGT)
2) Sulfation—PAPs
3) Mercapturic acid formation (GST)
4) N-, O-, S- methylation— SAM
5) Acetylation —Acetyl Co-A
4
Q
what xenobiotics can produce increases in drug metabolism for CYPs
A
Polycyclic aromatic hydocarbons Anticonvulsants Glucocorticoids Peroxisomes Rifampin St. John's Wort HIV drugs
5
Q
What xenobiotics can produce decreases in drug metabolism?
A
antibiotics (-mycins) Gemfibozil Azole-class antifungals HIV protease inhibitors 1st generation H2 antagonists (cimetidine) Grapefruit juice
