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Flashcards in Drug Drug Interactions Deck (72)
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1

What is a drug interaction

The modification of a drugs effect by prior or concomitant administration of another Drug, Herb, Foodstuff, Drink

2

When does a drug interaction occur

When the pharmacological effect of two or more drugs given together is not just a direct function of their individual effects

3

What type of drug interactions can occur

Drug - drug interactions
Herbal - drug interactions
Food - drug interactions
Drink - drug interactions
Pharmacogenetic interactions

4

What is an object drug

The drug whose activity is effected by such an Interaction

5

What is a precipitant

The agent which precipitates such an interaction

6

What factors can also modify drug action

Smoking
Alcohol

7

When are drug interactions not detrimental

The treatment of hypertension
The treatment of Parkinsonism with carbidopa and levadopa

8

What is carbidopa

A dopa decarboxylase inhibitor and prevents the systemic side effects from levadopa

9

How many patients are affected by detrimental interactions in hospitals

2.2-30%

10

How many patients are affected by detrimental interactions in GP's

9.2-70%

11

Name some drugs involved with serious interactions

Erythromicin
Clarithromicin
Warfarin
Gentamicin
SSRI
Lithium
Digoxin

12

What are some patient specific factors that can affect DDI's

Advanced age
Genetic polymorphioms
Concomitant diseases

13

What are some drug specific factors that can affect DDI's

Polypharmacy
Narrow therapeutic range
Dose

14

What are some other factors that can affect DDI's

Multiple prescribing physcians
Self prescribing

15

What do drugs involved in serious interactions have in common

They are all potent with a narrow therapeutic index
So a small change in blood levels can induce profound toxicity

16

What can prevent drug toxicity

Therapeutic drug monitoring

17

What foods can interact with warfarin

Asparagus
Broccoli
Brussel sprouts
Lettuce
Onions
Avocado
Fish oils
Green tea

18

What pateints are susceptible to DDI's

Elderly
Young
Critically ill
Patients undergoing complicated surgical procedures

19

What increases the probability of DDI's

Increases exponentially with the number of medicaments

20

What type of chronic conditions can make patients susceptible to DDI's

Liver disease
Renal impairment
Diabetes mellitus
Epilepsy
Asthma

21

What are the mechanisms of drug interactions

Pharmaceutical
Pharmacokinetic

22

What pharmacokinetic interactions can a drug alter

Absorption
Distribution
Metabolism
Elimination

23

What kind of pharmacodynamic interactions are there

Antagonistic Interactions
Additive or synergistic interactions
Interactions due to changes in drug transport
Interactions due to fluid and electrolyte disturbances
Indirect pharmacodynamic interactions

24

Why can potential interactions be predicted

As there is marked inter-individual variation in the ADME processes

25

What cannot be predicted

Who will have a clinically significant interaction

26

What mechanisms can be used to disrupt absorption interactions

Formation of insoluble complexes
Altered pH
Altered bacterial flora
Altered GIT motility

27

What do most type of DDI's involving absorption result in

Changes in absorption rate rather than the extent of absorption

28

When is delayed absorption important

When a drug has a short half life or when we want high plasma levels rapidly

29

What do most DDI's involving absorption cause and how can it be avoided

A delay in absorption
Avoided if 2-4 hours are left between administration of the drugs

30

Where do some drugs bind to each other

GI tract