Drug interactions

Question 0

goals of drug therapy

Answer 0

enhance desired therapeutic result

decrease drug induced toxicity

Question 1

Drug actions can

Answer 1

increase/decrease therapeutic or toxic effects

Question 2

some patients concerns about health system

Answer 2

suffering from pain
cost of prescriptions
wrong drug
drug interaction

Question 3

Pharmacokinetic

Answer 3

delivery of a drug to its site of action

Question 4

Pharmacodynamic

Answer 4

the response of drug target is modified

Question 5

Pharmacokinetic interactions

Answer 5

GI tract
plasma
liver
kidney

Question 6

Pharmacodynamic interactions

Answer 6

target organs

Question 7

interaction before administration

Answer 7

Phenytoin PPTs out of dextrose solution

Amp B PPTs in saline

Question 8

GI interactions that reduce entry of drugs into the systemic circulation

Answer 8

Metal containing drugs can reduce the absorption of expensive and life saving antibiotics
Some drugs require acidic environment to be in non charged form that is absorbed. Altered pH affects solubility

Question 9

Protein “bumping” interaction in serum can result in

Answer 9

increased amount of free drug

Question 10

metabolism and biotransformation refer to

Answer 10

disappearance of drug when it is changed chemically into another compound called a metabolite

Question 11

When drug is metabolized usually converted from what form to what form?

Answer 11

nonpolar, lipid soluble to more polar form than is more water soluble (this aids in excretion through urine)

Question 12

Advantages of prodrug

Answer 12

overcome potential destruction by stomach acid
minimize exposure to highly reactive chemical species
allow for selective generation of pharmacologically active metabolites at specific target sites in vivo

Question 13

Phase I

Answer 13

oxidations - P450 dependent
oxidations - P450 independent
Reduction/Hydrolyses - P450 independent

Question 14

Phase II

Answer 14

conjugation to -OH, -NH2, -SH
subgroups added
-glucuronate, acetate, glutathione, glycine, sulfate, methyl groups

Question 15

Phase I reactions - purpose

Answer 15

convert lipophilic molecules into more polar molecules by introducing or unmasking polar functional group

Question 16

Phase I reactions usually catalyzed by

Answer 16

CYPs

Question 17

Drug interactions due to hepatic metabolism

Answer 17

nearly always due to interaction at phase I enzymes

Question 18

CYPs most abundant to least

Answer 18

3A4
2C9
1A2
2E1

Question 19

CYP3A4

Answer 19

for metabolism of largest number of drugs
ex: Ca channel blocker, benzos, HIV protease inhibitors, HMG CoA, cyclosporine, non sedating antihistamines, cisapride
Present in GI and liver

Question 20

Inhibitors of CYP3A4

Answer 20

*Grapefruit juice
Antifungals - Ketoconazole, Itraconazole, Fluconazole
Ritonavir
Erythromycin, Clarithromycin

Question 21

Inducers of CYP3A4

Answer 21

Carbamazepine
Rifampin
*St. Johns wort
*Barbiturates - Phenobarbital

Question 22

CYP2D6

Answer 22

absent in 7% white ppl
Hyperactive in 30% East african
**metabolizes Codeine and beta-blockers

Question 23

Inhibitors of CYP2D6

Answer 23

Quinidine

Question 24

CYP2C9

Answer 24

*metabolizes NSAIDs (includes COX2)

Question 25

CYP2C9 inhibited by

Answer 25

Fluconazole

Question 26

CYP1A2 induced by

Answer 26

***Smoking tobacco

Question 27

CYP1A2

Answer 27

Propranolol

Question 28

CYP1A2 inhibited by

Answer 28

*Cimetidine - Histamine antagonist, lowers stomach pH

Question 29

Phase I reactions that do NOT involve CYPs

Answer 29

Amine oxidation Dehydrogenation Reduction Hydrolyses

Question 30

Phase I prepares very ...

Answer 30

lipophilic molecules for phase II reactions by creating a conjugation site

Question 31

Phase II reactions conjugate

Answer 31

a water soluble entity to aid in excretion by making molecule more polar, helps to eliminate it via urine or bile

Question 32

If metabolite for Phase I metabolism is sufficiently polar,

Answer 32

can be excreted by kidneys without need for conjugation

Question 33

if drug is too lipophilic

Answer 33

retained in the kidney tubules

Question 34

drugs with -OH, -NH2, or COOH group

Answer 34

may enter Phase II directly

Question 35

A highly polar drug conjugate may be

Answer 35

excreted by the kidney or bile

Question 36

Cardiac disease

Answer 36

can decrease hepatic blood flow

Question 37

St john wort with Indinavir

Answer 37

inhibits the drug activity | on a graph, would see lower concentration of Indinavir over the course of treatment

Question 38

Drug metabolites are generally more

Answer 38

polar than the parent drug

Question 39

most studied drug transporter

Answer 39

P-glycoprotein

Question 40

Inhibitor of P-glycoprotein

Answer 40

verapamil, ditiazem | these inhibitors will elevate levels of drug because they cant be transported for elimination

Question 41

warfarin plus NSAIDs

Answer 41

BAD - gastric bleeding