Pharmacology Class 2020 Metabolism and Elimination Flashcards
(72 cards)
Metabolism
Important for activation and termination of biological and pharmacological activity
Main site of metabolism
Liver
Active Metabolites
Product of metabolism which has pharmacologic effect such as morphin turning into morphine 6 glucurpnide
Inactive Metabolites
Product of metabolism without pharmacologic effect
Toxic Metabolites
Metabolite with harmful properties that have toxic effects.
Example:
Morphin can be broken down into MG3 morphine 3 glucuronide which can potentially buildup in a patient with renal disease which can cause seizures in patients.
Why is morphin so strong?
Because it produces strong metabolites
When does a drug have a pharmacologic effect?
When it reaches the site where it is metabolized
Prodrug
Metabolism of a prodrug produces the active metabolite
Heroin or morphine is more analgesia
Heroin because it can cross BBB.
First Pass Effect
After the drug is taken by mouth and then it goes to stomach and then gastric emptying into small intestines. It must go to portal vein before getting introduced to systemic circulation.
Metabolism can dramatically reduce concentration of drug
How does First Pass Effect affect concentration of the drug
Lowers it and therefore the drug has a weaker effect and decrease in bioavalability
Researchers want to make sure that a drug can withstand the First Pass Effect
True
How is bioavalability affected by First Pass Effect?
It decreases it
IV route of drug does not need to meet liver first before getting to bloodstream.
True or False
True
Transdermal transmit drug from dermis to bloodstream.
True or False
True
What does rectal route do in First Pass Effect?
Partial avoidance of First Pass Effect
Enterohepatic Recycling
When a drug is introduced to the liver it can recycle itself and get reintroduced back into the GI by some of the drug not being metabolized and it gets packed up with bile acid and returned back into the gut.
What is the main advantage of Enterohepatic Recycling?
Prolong’s drug’s systemic availabilty and duration of therapeutic or toxic effect.
What are the phases of drug metabolism?
Phase 1= produce active or inactive metabolites. Many Pro drugs are activated here.
Phase 1 Enzymes
Cytochrome P450 are responsible for metabolizing the majority of drugs in the liver.
Flavin Containing Monooxygenase FMO
When a drug is less polar or lipophillic due to unmasking a functional group what happens to the drug?
It is eliminated because it has less permeability which traps it for elimination.
What type of reactions occur in phase 1?
5-oxidation N-Oxidation Oxidatio Dealkylation Cytochrome P 450 dependent oxidation Epoxidation
What are the enzymes of CYP for drug metabolism?
CYP3A4
CYP2D6
CYP2C9
CYP1A2
Phase 2
Reactions involving addition of subgroups such as
Glucoronate Acetate Glithathione Glycine Su;fate Methyl Groups