Drug Interactions Flashcards Preview

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Flashcards in Drug Interactions Deck (38)
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1
Q

What factors modify drug interactions

A
Drug - drug interactions.
Herbal - drug interactions.
Food - drug interactions.
Drink - drug interactions.
Pharmacogenetic interactions.
2
Q

Define object drug

Define percipient drug

A

Drug whose activity is effected by such an interaction

Agent which percipitates such a reaction

3
Q

What drugs are most likely to cause a drug interaction

A

Drugs with a low therapeutic margin

4
Q

What are examples of herbs that can cause drug interactions

A
➢	Ginseng
	➢	 Green teas
	➢	 Melilot
	➢	 Tonka beans
	➢	 Woodruff
5
Q

What are the characteristics of susceptible patients

A
number of medicaments
Advanced age 
Young
the critically ill
patients undergoing complicated surgical procedures
6
Q

What is 5 examples of patients with chronic diseases that can induce drug interactions

A
Liver 
Renal 
Diabetes 
Epilepsy 
asthma
7
Q

What are further examples of things that can cause drug interactions

A

Multiple prescribing physicians
Self prescription
Prolonged length of stay (hospital infections)

8
Q

What are examples of pharmodynamics interactions that can cause a drug interaction

A

Antagonistic Interactions
direct agonism
Indirect agonism
Additive or synergistic interactions

changes in drug transport
fluid and electrolyte disturbances

9
Q

What is an example of an antagonist interaction

A

beta-blockers such as atenolol will block the actions of agonists e.g. bronchodilators such as salbutamol

10
Q

What happens in a synergist drug interaction do

A

When two drugs with same pharmological effect acting on the same receptor

11
Q

What is a phrarmodynamic interaction

A

the phrarmodynamic interactions of a drug are changed due to the presence of another drug

12
Q

What are examples of indirect agonism that Induce CNS depression

A
Benzodiazepines 
tricyclics 
alcohol
Warfarin 
NSAIDs (Indomethacin)
Atenolol 
verapamil
13
Q

What are NSAIDs indirect antagonists for

A

antihypertensive medication

treatment for heart failure

14
Q

In pharmokinetic drug interactions it is possible for one drug to alter what four factors?

A

Absorption
Metabolism
Distribution
Elimination

15
Q

What are the absorption interactions caused by drugs

A

Formation of insoluble complexes
Altered PH.
Altered bacterial flora..
Altered GIT motility.

16
Q

What kind of antibiotics destroy normal gut flora

A

Broad spectrum

17
Q

What is the possible outcomes of destroyed gut flora

A

Oral contraceptive

digoxin toxicity

18
Q

When is delayed absorption important

A

Drug has short half life

want high plasma levels rapidly

19
Q

What does tetracycline and erythromicin form a complex with

A

iron, calcium, magnesium

20
Q

What drugs can increase the pH

A

H2 antagonists,
proton pump blockers
antacids

21
Q

Drug binding in the GI tract is affected by

A

the degree of ionisation

22
Q

What are examples of what Cholestyramine resin binds to in the GI tract

A

warfarin, digoxin

23
Q

What is an example of a rate limiting step in absorption

A

Gastic emptying time

24
Q

What are example of drugs that delay gastric emptying time

A

anticholinergics,
tricyclic anti-depressants,
opiates

25
Q

When does protein displacement occur

A

when there is a reduction in the extent of plasma protein binding of a drug caused by the presence of another drug

26
Q

The displacement of a drug from plasma proteins results in the increase of

A

Bioavailability of the displaced drug

27
Q

When does drug interaction involving metabolism occur

A

when drug induces or inhibits the metabolism of another

28
Q

Where does metabolism occur

A

In the liver via the cytochrome P450 system

29
Q

What are examples of drug that inhibit metabolism

A
clarithromycin, 
erythromycin, 
cimetidine, 
ketoconazole, 
omeprazole, 
Metronidazole 
CCBs (diltiazem)
(claire ejects cool kids over the moon)
30
Q

What is warfarin inhibited by

A

Metronidazole
Omeprazole
cimetidine,

31
Q

What drugs induce metabolism

A
barbiturates, 
carbamazepine, 
phenytoin, 
rifampacin 
tobacco smoke
32
Q

The effect of enzyme inducers are usually

A

delayed 2-3 weeks

33
Q

What us enzyme induction dependant on

A

age,
disease,
genetics
concurrent drug therapy

34
Q

What can Rifampacin and Phenytoin induce

A

warfarin

35
Q

What can induce steroids

A

Phenytoin

36
Q

What can effect the elimination of drugs

A

Changes in GFR or tubular secretion

37
Q

What can inhibit excretion

A

Verapamil/diltiazem

digoxin

38
Q

What increase tubular reabsorption

A

lithium

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