Exam 1: Metabolism of Drugs Flashcards
The Chemical alteration of the drug molecule by the cells of the animal
Metabolism of drugs
What are the 2 main effects of drug biotransformation
- change in physicochemical properties of the drug
2. change in pharmacologic activity
What is more common, Bioinactivation or bioactivation
Bioinactivation
What is the main site of Biotransformation
Liver
Other than the liver list some other tissues capable of biotransformation
Nervous tissue, Kidney, GI, lungs, skin, plasma
What are the 4 types of biotransformation
- Active drug to inactivated
- Active drug to active metabolite
- inactive drug to active metabolite
- Nontoxic drug to toxic metabolite
What are the two toxic metabolites in Antifreeze toxicity
Glycoaldehyde and glycoxylate
Refers to large groupings of enzymes that tackle a variety of chemical substances
Microsomal enzymes
T/F. Enzymatic rxns are not saturable
F
Enzymes can be ____ or _____ by other drugs
induced or inhibited
Microsomal enzymes cause what 4 things to glucuronic acid
- Oxidation
- reduction
- hydrolysis
- conjugation
What are the 2 types of metabolic Rxns
- Phase 1 rxns
2. Phase 2 rxns
what are the 3 types of phase 1 rxns
- Oxidation
- Reduction
- Hydrolysis
What is the only type of phase 2 rxn.
conjugation
What is another name for phase 2 rxns.
Synthetic
What is another name for phase 1 rxn.
Nonsynthetic
The loss of one or more electrons
oxidation
The gain of one or more electrons
Reduction
The splitting of a molecule into fragments by the addition of water
Hydrolysis
Oxidation or reduction
Gain O2 or remove H+
Oxidation
Oxidation or reduction
Gain H+ or Remove O2
Reduction
What is the most common biotransformation
Oxidation
T/F. all phase 1 products move on to phase 2
F
Which type of drug must go through phase 2 prior to excretion
Lipid soluble
What is a conjugation rxn.
combination of a drug or its metabolite with an endogenous substance
Who is deficient in conjugation rxns.
Cats and neonates
Metabolite conjugates are usually ____, _____, and _____
Inactive, Water soluble, and Non-toxic
What is the one conjugation rxn that is microsomal
Glucuronidation
Conjugation to ____ is the most common conjugation reaction
Glucuronic Acid
Dogs are deficient in ____
Acetylating enzymes
Ruminants have less plasma ______ than horses, dogs, or cats
pseudocholinesterase
Pigs are deficient in ____ enzymes
sulfate conjugatin
Birds lack ___ enzymes
Oxidative
What is the 3 criteria of hepatic first pass metabolism
- drug must go to liver before circ.
- drug must be metabolized by the liver
- must have high hepatic extraction ratio
what is the result of hepatic first pass metabolism
drug metabolized before distribution
Drug that stimulates the liver to produce more metabolic enzymes
Enzyme inducers
Drugs that inhibit liver production of metabolic enzymes
Enzyme inhibitors
Bioactivation transforms the drug into an _____ compound first
Active
Lethal transformation transforms nontoxic drugs into ____
toxic
T/F First pass metabolism results in dec. oral drug bioavailability
T
