Drug Interactions Flashcards Preview

CMBM exam 4 > Drug Interactions > Flashcards

Flashcards in Drug Interactions Deck (33):
1

What can drug interactions do?

Reduce therapeutic effects
Increase therapeutic effects
Inc or reduce toxicity

2

What are common outlets for drug therapy?

Hypertension
Heart failure
Pain
Cancer

3

What are the goals of combination drug therapy?

Enhance desired therapeutic results
Dec drug induced toxicity

4

What are some classifications of drug interactions?

Pharmacokinetic (delivery of a drug to site of action altered by second drug)
Pharmacodynamic (response of the drug target is modified by a second drug)

5

Where do pharmacokinetic interactions take place?

GI, plasma, liver, kidney

6

Where do pharmacodynamic interactions take place?

Target organ

7

What interaction can occur in the GI tract?

Interactions can reduce the entry of drugs into the systemic circulation

8

What are some drugs that reduce systemic entry to the GI tract?

Aluminum containing medicines
Sucralfate reduced absorption to Ciprofloxacin and Azithromycin
omepazole (raise stomach PH)

9

What are some interactions that happen before administration?

Phenytoin is precipitates dextrose solution
Amphotericin precipitates in saline

10

What is protein bumping?

Interactions in serum that can cause an increased amount of free drug

11

What does metabolism of biotranformation refer to?

Disapperance of a drug when it changed chemically into another compound - a metabolite

12

What is the basic chemical process for a drug being metabolized?

Converting of a nonpolar, lipid-soluble compound to a more polar form that is more water soluble and can be readily excreted in the urine

13

What is the spectrum of cosequences of drug metabolism?

Inactive products (majority)
Active metabolites
Similar to parent drug
New action
Toxic metabolites

14

What are prodrugs (drugs in less actiev or inactive form) administered for?

Absorption
Overcome potential destruction by stomach acid
Minimize expose to high reactive chemical species
Allow for selective generation of active metabolites at target in vivo

15

What is cytochrome P450 (mixed function oxidases)?

A group of enzymes that are hemoproteins

16

What is Phase I of drug metabolism?

Oxidation (P450 dependent)
Oxidations (P450 independent)
Reduction
Hydrolyses

17

What is Phase II of drug metabolism?

Conjugation to -OH, -NH2 and -SH functions on drug molecule
Subgroups added

18

What are some phase I reactions?

Function to convert lipophilic molecules to more polar molecules bu introducing (unmasking) a polar functional group (OH, NH2, SH)
Most frequently involved in drug metabolism are catalyzed my microsomal mixed function oxidases

19

What are drug interactions due to hepatic metabolism?

Due to interaction at phase I enzymes
(P450 common)

20

What are the most common and important CYP450?

CYP3A4 (30%)
CYP2C9 (20%)
CYP1A2 (15%)

21

What is the Cytochrom P450 nomenclature for CYP2D6?

CYP = cytochrome P450
2 = genetic family
D = genetic subfamily
6 = specific gene

22

What is CYP3A4 responsible for in terms of metabolism?

Most calcium channel blockers
Benzos
HIV PIs
HMG-CoA reductase inhibitors
Cyclosporine
Non-sedating antihistamines
Cisapride

23

Where would CYP3A4 be found?

GI tract and liver

24

What is the main form of CYP inhibitors?

Through competition for the same isozyme

25

What are some drugs which are CYP3A4 inhibitors?

Ketoconazole
Itraconazole
Fluconazle
Cimetidine
Grape fruit juice
Amiodarone
Ritonavir

26

What are some CYP3A inducers?

Carbamazepine
Rifampin
Phenobarital
Phenytoin

27

What is the action of cytochrome P450 2D6?

Catalyzes primary metabolism of codeine, B-blockers and trucyclic antidepressants

28

What is CYP2D6 inhibited by?

Fluoxetine

29

What does CYP2C9 primarily metabolize?

Most NSAIDS (COX-2)
S-warfarin (active)
Phenytoin

30

What is CYP2C9 inhibited by?

Fluconazole

31

Which CYP is induced by smoking tobacco?

CYP1A2

32

What does CYP1A2 primarily catalyze in metabolism?

Theophylline
Imipramine
Propranolol
Clozapine

33

What inhibits CYP1A2?

Many fluorquiolone antibiotics
Fluvoxamine
Cimetidine