Drug Interactions

Question 1

What factors modify drug interactions

Answer 1

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

Question 2

Define object drug

Define percipient drug

Answer 2

Drug whose activity is effected by such an interaction

Agent which percipitates such a reaction

Question 3

What drugs are most likely to cause a drug interaction

Answer 3

Drugs with a low therapeutic margin

Question 4

What are examples of herbs that can cause drug interactions

Answer 4

➢	Ginseng
	➢	 Green teas
	➢	 Melilot
	➢	 Tonka beans
	➢	 Woodruff

Question 5

What are the characteristics of susceptible patients

Answer 5

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

Question 6

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

Answer 6

Liver 
Renal 
Diabetes 
Epilepsy 
asthma

Question 7

What are further examples of things that can cause drug interactions

Answer 7

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

Question 8

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

Answer 8

Antagonistic Interactions
direct agonism
Indirect agonism
Additive or synergistic interactions

changes in drug transport
fluid and electrolyte disturbances

Question 9

What is an example of an antagonist interaction

Answer 9

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

Question 10

What happens in a synergist drug interaction do

Answer 10

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

Question 11

What is a phrarmodynamic interaction

Answer 11

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

Question 12

What are examples of indirect agonism that Induce CNS depression

Answer 12

Benzodiazepines 
tricyclics 
alcohol
Warfarin 
NSAIDs (Indomethacin)
Atenolol 
verapamil

Question 13

What are NSAIDs indirect antagonists for

Answer 13

antihypertensive medication

treatment for heart failure

Question 14

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

Answer 14

Absorption
Metabolism
Distribution
Elimination

Question 15

What are the absorption interactions caused by drugs

Answer 15

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

Question 16

What kind of antibiotics destroy normal gut flora

Answer 16

Broad spectrum

Question 17

What is the possible outcomes of destroyed gut flora

Answer 17

Oral contraceptive

digoxin toxicity

Question 18

When is delayed absorption important

Answer 18

Drug has short half life

want high plasma levels rapidly

Question 19

What does tetracycline and erythromicin form a complex with

Answer 19

iron, calcium, magnesium

Question 20

What drugs can increase the pH

Answer 20

H2 antagonists,
proton pump blockers
antacids

Question 21

Drug binding in the GI tract is affected by

Answer 21

the degree of ionisation

Question 22

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

Answer 22

warfarin, digoxin

Question 23

What is an example of a rate limiting step in absorption

Answer 23

Gastic emptying time

Question 24

What are example of drugs that delay gastric emptying time

Answer 24

anticholinergics,
tricyclic anti-depressants,
opiates

Question 25

When does protein displacement occur

Answer 25

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

Question 26

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

Answer 26

Bioavailability of the displaced drug

Question 27

When does drug interaction involving metabolism occur

Answer 27

when drug induces or inhibits the metabolism of another

Question 28

Where does metabolism occur

Answer 28

In the liver via the cytochrome P450 system

Question 29

What are examples of drug that inhibit metabolism

Answer 29

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

Question 30

What is warfarin inhibited by

Answer 30

Metronidazole Omeprazole cimetidine,

Question 31

What drugs induce metabolism

Answer 31

``` barbiturates, carbamazepine, phenytoin, rifampacin tobacco smoke ```

Question 32

The effect of enzyme inducers are usually

Answer 32

delayed 2-3 weeks

Question 33

What us enzyme induction dependant on

Answer 33

age, disease, genetics concurrent drug therapy

Question 34

What can Rifampacin and Phenytoin induce

Answer 34

warfarin

Question 35

What can induce steroids

Answer 35

Phenytoin

Question 36

What can effect the elimination of drugs

Answer 36

Changes in GFR or tubular secretion

Question 37

What can inhibit excretion

Answer 37

Verapamil/diltiazem | digoxin

Question 38

What increase tubular reabsorption

Answer 38

lithium