Drug Interactions

Question 1

Drugs can interact with…

Answer 1

Other drugs
Disease States
Food and Drinks
Alcohol

Question 2

What is a Drug-Drug Interaction

Answer 2

Whenever one drugs affects the PK,PD,efficacy or toxicity of another drug

Question 3

Object drug is…

Answer 3

Drug affected by the interaction

Question 4

Precipitant drug is…

Answer 4

drug causing the interaction

Question 5

Antagonistic effect?

Answer 5

one drug lessens effects of another

Question 6

Additive effect?

Answer 6

both drugs result in an increased effect

Question 7

Synergistic effect?

Answer 7

both drugs result in an increased effect more than just the addition of both

Question 8

Idiosyncratic effect?

Answer 8

Response is unexpected from the known effects of either drug

Question 9

Pharmacodynamic MOA drug interaction

Answer 9

one drug induces change in patients response to drug without altering drugs PK

Question 10

Pharmacodynamic MOA drug interaction

Answer 10

one drug alters rate or extent of ADME of another drug

Question 11

Examples of Additive effects

Answer 11

Additive anticholinergic effects

ACE-I and Spironolactone

Combo of drugs that prolong QT interval

Question 12

Examples of Antagonistic effects

Answer 12

NSAID inhibit antihypertensive effects of ACE-I

Question 13

PK absorption

Answer 13

Inhibition:
Precipitant drug impairs bioavailability of object drug, resulting in decreased therapeutic effect of object drug

Common percipients

Binding agents (Cholestyramine)
Cations (Al,Mg,Fe)
Altered stomach pH

Caution: Rate vs Extent

Question 14

Most important plasma proteins for PK distribution

Answer 14

Albumin
Alpha-1-acid glycoprotein
Lipoproteins

Question 15

Biggest portion of Drug-Drug interactions?

Answer 15

Metabolism

Question 16

What do all CYP450 have?

Answer 16

Central Heme Unit

Question 17

CYP450: Those with Wild Type alleles..

Answer 17

Extensive metabolizers

Question 18

CYP450: Those with nonfunctional or missing alleles…

Answer 18

Poor metabolizers

Question 19

CYP450: Those with alleles with repeated gene copies….

Answer 19

Ultra Rapid metabolizers

Question 20

Co-admin of CYP450 inhibitors can…

Answer 20

convert EM to PM

Question 21

Where do issues come with CYP450 metabolism and potential for drug interactions?

Answer 21

When drug has an affinity to 1 particular CYP enzyme instead of a variety of them.

Question 22

(in gut) P-gp info

Answer 22

transports drug molecules out of cells. tries to keep drug from getting into plasma, sends back to intestinal lumen

net effect is decrease drug in systemic circulation

found in intestines/liver/kidney

Question 23

(in gut) P-gp inhibition will result in….

Answer 23

increased bioavailability and drug effect

Question 24

(in gut) P-gp induction will result in…

Answer 24

decreased bioavailability and drug effect

Question 25

(Liver/Kidney) P-gp inhibition will result in…

Answer 25

decrease metabolism/excretion

Increase drug effect

Question 26

(Liver/Kidney) P-gp induction will result in…

Answer 26

increase metabolism/excretion

Decrease drug effect

Question 27

(Liver/Kidney) P-gp info

Answer 27

acts to increase excretion of drug by transporting molecules into bile and urine

Question 28

Phase I enzyme?

Answer 28

Flavin monooxygenases

Question 29

Phase II enzymes?

Answer 29

UGTs

Question 30

Drugs that are strong inhibitors or inducers of drug metabolizing enzymes or transporters?

Answer 30

Clarithromycin

Carbamazepine

Question 31

Drugs with serious dose dependent adverse effects or narrow TI

Answer 31

Statins
Calcium Channel Blockers
Methotrexate
Oral anticoagulants
Antipsychotics
Opioids