Term
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Definition
| the combined effect of two drugs is the sum of the individual effects |
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Term
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Definition
- drug-drug interactions
- food-drug interactions
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Term
| Interaction(medical definition) |
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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 |
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Term
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Definition
| interactions between medications. they fall into two main categories: pharmacodynamic, and pharmacokinetic |
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Term
| two main catagories of drug-drug interactions |
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Definition
pharmacodynamic
pharmacokinetic |
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Term
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Definition
| involving the actions of the two interacting drugs |
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Term
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Definition
| involving the absorption , distribution, metabolism, and excretion of one or both of the interacting drugs upon the other. |
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Term
| a drug drug interaction may result in: |
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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. |
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Term
| pharmacokinetic drug interaction |
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Definition
| a change in blood concentration causes a chang ein the drug's effect |
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Term
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Definition
H2 blockers and ketoconazole
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Term
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Definition
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Term
| change in gastrointestional flora |
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Definition
| anticoagulants and antibiotics |
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Term
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Definition
| metoclopramide and acetaminophen |
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Term
| malabsorption caused by other drugs |
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Definition
| orlistat (xenical) and fat soluble vitamins |
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Term
| ways in which absorption is affected by pharmacokinetic interactions |
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Definition
- change in GI pH
- drug binding in GI tract
- change in GI flora
- Change in GI motility
- malabsorption caused by other drugs
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Term
| how do drug interactions affect Distribution? |
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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
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Term
| warfarin and phenylbutazone |
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Definition
| one may displace the other from the binding sites/proteins affecting distribution |
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Term
metabolism: enzyme induction
drugs that cause this? |
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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 |
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Term
| phenobarbital and warfarin |
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Definition
| cause metabolism enzyme induction |
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Term
| drugs that inhibit metabolism |
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Definition
the normal pace of metabolism is slowed so the drug begins to accumulate in the body
ex: cimetidine and theophylline |
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Term
| how excretion can be affected from drug-drug interactions |
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Definition
- the drug becomes ineffective or toxic
- increase in renal blood flow
- inhibition of active tubular secretion
- alterations in tubular reabsorption
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Term
| drugs that increase renal blood flow |
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Definition
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Term
| Drugs that Inhibit active tubular secretion (effecting excretion) |
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Definition
| Probenecid and penicillin |
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Term
| drugs that alter tubular reabsorption (affecting excretion) |
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Definition
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Term
pharmacodynamic drug interactions
5 types |
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Definition
- additive
- summation
- antagonism
- synergism
- potentiation
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Term
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Definition
combined effect of the two drugs giving the SAME response by the SAME mechansim
2+2=4
example: Asprin and Acetaminophen |
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Term
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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 |
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Term
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Definition
the combined effect of the two drugs is less than the sum of the individual effects
1+1=0
ex: Acetylcholine and Atropine |
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Term
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Definition
when two drugs produce a larger response than the sum of the individual effects
2+2 = 10
ex: barbiturates + alcohol |
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Term
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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 |
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Term
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Definition
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Term
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Definition
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Term
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Definition
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Term
| beta blockers and calcium channel antagonists |
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Definition
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Definition
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