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level: Metabolism

Questions and Answers List

level questions: Metabolism

Question	Answer
The biochemical changes that occur on drugs or other foreign compounds, the purpose of which is to facilitate elimination from the body	Drug Metabolism
Without Drug Metabolism, __ can remain indefinitely in the body	xenobiotics (substances that are foreign to the body)
Some metabolites are not only active, but may be __	toxic
Most metabolic products are less pharmacologically active a. True b. False	a. True exceptions; Where the metabolite is more active Where the metabolite is toxic Where the metabolite is carcinogenic
metabolite is more active Inactive drug is converted to active metabolite	Prodrugs ex. Erythromycin-succinate
the metabolite is toxic	acetaminophen
It causes conversion of an active drug to inactive or less active metabolites called as what?	pharmacological inactivation
It causes conversion of an active to more active metabolite called as what?	bioactivation or toxicological activation
It causes conversion of an inactive drug to active metabolites called as what?	pharmacological activation
What are the advantages of Prodrugs?	1 Increased absorption 2 Elimination of an unpleasant taste 3 Decreased toxicity 4Decreased metabolic inactivation 5 Increased chemical stability 6 Prolonged or shortened action
Sites of Drug Biotransformation	1 Gastrointestinal Tract 2 Liver 3 Blood Circulation
It means drug metabolism occurring before the drug enters the systemic circulation	First Pass Metabolism
First Pass Metabolism results in what?	Decreased bioavailability Decreased therapeutic response
Intestinal Mucosa, the extra-hepatic metabolism, contains what enzyme?	CYP3A4 isozyme
exhibit considerable sulphate conjugation in GI tract	Isoproterenol
Presence of these in the intestine may be important in carrying out hydrolysis of many ester prodrugs	Esterases and Lipases
Bacterial flora present in the intestine and colon reduce many __ and __ drugs	1 azo 2 nitro
Can hydrolyze glucuronide conjugates excreted in the bile, thereby liberating the free drug or its metabolite for possible reabsorption	Intestinal beta-glucuronidase
Metabolic Enzymes	1 Microsomal enzymes 2 Non-microsomal enzymes
1 Microsomal enzymes are found in __ 2 Non-microsomal enzymes are found in __	1 Smooth ER of liver cells 2 Cytoplasm and mitochondria of liver cells
It is a pigment that, with CO bound to the reduced form, absorbs maximally at 450nm	Cytochrome P450 (Hemoprotein)
Converts the parent drug to a more polar metabolite by introducing or unmasking a functional group (-OH, -NH2, -SH, -COOH).	Phase I 'Functionalization reactions'