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lab 9
SJU drug interaction
35
Pharmacology
Professional
04/18/2012

Additional Pharmacology Flashcards

 


 

Cards

Term
additive interaction
Definition
the combined effect of two drugs is the sum of the individual effects
Term
2 possible interactions
Definition
  1. drug-drug interactions
  2. food-drug interactions
Term
Interaction(medical definition)
Definition
when the pharmacological effects of one drug are changed by the presence of another drug, food, drink, or by some environmental or chemical agent
Term
drug-drug interactions
Definition
interactions between medications. they fall into two main categories: pharmacodynamic, and pharmacokinetic
Term
two main catagories of drug-drug interactions
Definition

pharmacodynamic

 

pharmacokinetic

Term
pharmacodynamic
Definition
involving the actions of the two interacting drugs
Term
pharmacokinetic
Definition
involving the absorption , distribution, metabolism, and excretion of one or both of the interacting drugs upon the other.
Term
a drug drug interaction may result in:
Definition

1. effect not seen with either of the drugs when taken alone.

 

2. inhibition of the effect of a drug by another drug

 

3. an increase in the effect of one of the drugs by another drug

 

4. no change in the net effect although pharmacokinetics and/or metabolism of one or both drugs may be altered.

Term
pharmacokinetic drug interaction
Definition
a change in blood concentration causes a chang ein the drug's effect
Term
change in GI pH
Definition

H2 blockers and ketoconazole

 

Term
drug binding in GI tract
Definition
Tetracycline and antacid
Term
change in gastrointestional flora
Definition
anticoagulants and antibiotics
Term
change in GI motility
Definition
metoclopramide and acetaminophen
Term
malabsorption caused by other drugs
Definition
orlistat (xenical) and fat soluble vitamins
Term
ways in which absorption is affected by pharmacokinetic interactions
Definition
  • change in GI pH
  • drug binding in GI tract
  • change in GI flora
  • Change in GI motility
  • malabsorption caused by other drugs
Term
how do drug interactions affect Distribution?
Definition
  • competition for protein binding
    • reversible binding of drugs to plasma proteins. only unbound molecules are free and active.  
  • displacement from tissue binding sites/proteins 
    • a drug can compete with another and displace it from the site is is occupying. this is based on the relative affinities for binding sites
    • ex: warfarin and Phenylbutazone 
Term
warfarin and phenylbutazone
Definition
one may displace the other from the binding sites/proteins affecting distribution
Term
metabolism: enzyme induction 

drugs that cause this?
Definition

the pace of metabolism increases so the drug gets eliminated faster as time goes on. you need a larger dose to get the same effect 


Phenobarbital and warfarin 

Term
phenobarbital and warfarin
Definition
cause metabolism enzyme induction
Term
drugs that inhibit metabolism
Definition

the normal pace of metabolism is slowed so the drug begins to accumulate in the body

 

ex: cimetidine and theophylline 

Term
how excretion can be affected from drug-drug interactions
Definition
  • the drug becomes ineffective or toxic
  • increase in renal blood flow
  • inhibition of active tubular secretion
  • alterations in tubular reabsorption 
Term
drugs that increase renal blood flow
Definition
Hydralazine and Digoxin
Term
Drugs that Inhibit active tubular secretion (effecting excretion)
Definition
Probenecid and penicillin
Term
drugs that alter tubular reabsorption (affecting excretion)
Definition

antacids + asprin 


 

Term

pharmacodynamic drug interactions

 

5 types 

Definition
  1. additive
  2. summation
  3. antagonism
  4. synergism
  5. potentiation 
Term
additive
Definition

combined effect of the two drugs giving the SAME response by the SAME mechansim 

 

2+2=4

example: Asprin and Acetaminophen

Term
summation
Definition

the combined effect of the two drugs produce the same response but BY DIFFERENT MECHANISMS 

 

2+2=4

ex: Beta blockers and calcium channel antagonists 

Term
Antagonism
Definition

the combined effect of the two drugs is less than the sum of the individual effects

 

1+1=0

 

ex: Acetylcholine and Atropine 

Term
Synergism
Definition

when two drugs produce a larger response than the sum of the individual effects 

 

2+2 = 10

 

ex: barbiturates + alcohol 

Term
Potentiation
Definition

when a drug which has little or no effect can enhance the effect of another drug 

 

0+1 =2

2+10 =25

 

ex: antihistamine + narcotic

Term
antihistamine + narcotic
Definition
potentiation interaction
Term
Barbiturates + alcohol
Definition
synergism interaction
Term
acetylcholine + atropine
Definition
antagonism interaction
Term
beta blockers and calcium channel antagonists
Definition
summation interaction
Term
asprin and acetaminophen
Definition
Additive effect
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