Drug Interactions - Quiz 2

Question 1

What is pharmacodynamics?

Answer 1

The effect or change that a drug has on the body

Question 2

What drugs are affected by coadminstration with polyvalent cations?

Answer 2

Quinolones, tetracyclines, levothyroxine, bisphosphonates

Question 2

What is pharmacokinetics?

Answer 2

The effect the body has on the drug

Question 3

What is the primary enzyme expressed in the liver?

Answer 3

CYP450

Question 3

What drug blocks the renal excretion of penicillin?

Answer 3

Probenacid

Question 4

What are prodrugs?

Answer 4

Inactive drug that is converted by CYPs to an active drug

Question 5

What are the benefits of prodrugs?

Answer 5

1. INcrease bioavailability
2. Prevent drug abuse

Question 6

What is the activity of prodrugs in the presence of CYP inhibiutors and inducers?

Answer 6

Inhibitors: concentration of active drug decreases
Inducers: concnetration of active drugs inrease

Question 7

What are the most common CYP inhibitors?

Answer 7

Grapefruit
Protease Inhibitors
Azole
Cyclosporine, cobicistat
Macrolides (clarithromycin and erythomycin)
Amiodarone
Non-DHP CCBs (diltiazem and verapamil)

Question 8

What are the common CYP inducers?

Answer 8

Phenytoin
Smoking
Phenobarbital
Oxcarbazepine
Rifampin
Carbamazepine
St John’s wort

Question 9

How long in the lag time when an inducer has been discontinued?

Answer 9

2-4 wks

Question 10

Common Pgp substrates?

Answer 10

Anticoagulants: apixaban, rivaroxaban
CV drugs: digoxin, diltiazem, verapamil
Immunosuppressants: cyclosporine, tacrolimus
Colchicine

Question 11

Common pgp inducers?

Answer 11

Carbamazepine, phenobarbital, phenytoin, rifampin, St Johns

Question 12

Common pgp inhibitors?

Answer 12

CV: amiodarone, diltiazem, verapamil
HIV: cobicistat, ritonavir
Cyclosporine

Question 13

When adding warfarin to amiodarine what do you need to adjust? Vice versa?

Answer 13

Warfarin at low dose ≤5 mg

Decrease warafarin dose by 30-50% depending on INR

Question 14

What is the cause of amiodarone and warfarin interaction?

Answer 14

Amiodarone is a CYP2C9 inhibitor increasing risk for bradycardia (Check for other drugs: beta blockers, clonidine, diltiazem, verapamil for decreased HR)

Reduse PO digoxin 50% when adding on amiodarone

Question 15

What is the cause of amiodarone and digoxin interaction?

Answer 15

Amiodarone inhibits pgp

Question 16

What electrolytes are decreased by loop diuretics? digoxin?

Answer 16

K, Mg, Ca, Na

Decreased K and Mg, increased Ca

Question 17

What are drugs that decrease HR? How should you monito?

Answer 17

Amiodarone,digoxine, clonidine, beta blockers, diltiazem, verapamil

Monitor HR: 60-100 BPM

Question 18

What statins are increaed with conmittant use of strong CYP3A4 inhibitors? How do you address interaction?

Answer 18

Lovastatin, simvastatin, atorvastatin

Non-CYP statins: pitavastatin, pravastatin, rosuvastatin

Question 19

What enzyme metabolizes waraafarin?

Answer 19

CYP2C9

Inhibitors-> Increased levels -> Increased INR and bleeding risk
Inducers -> derease levels -> decreased INR and increases clotting risk

Question 20

What should not be taken with CYP3A4 substrates?

Answer 20

Grapefruit juice

Question 21

How do you does lamotrigine and valproate together?

Answer 21

Starter kit initiates lamotrigine with lower doses and tritates every 2 wks

Question 22

MOA inhibitors increases what catecholamines?

Answer 22

Epi, NE, DA, 5-HT

Hypertensive crisis and serotonin syndrome

Question 23

Counseling points of MAOIs?

Answer 23

2 wk wash out period when switching between MOAI and serotonergic agents * 5 weeks if initiating fluoxetin Avoid tyramine containig foods (aged cheeses, dried meats, sauerkraut)

Question 24

What opioid are CYP3A4 substrates?

Answer 24

Fentanyl, hydrocodone, oxycodone, methadone

Question 25

Smoking induces what CYP enzyme?

Answer 25

1A2

Question 26

What drugs increase risk for bleeding?

Answer 26

1. Anticoags 2. Antiplatelets 3. NSAIDs 4. SSRIs, SNRIs 5. Garlic, ginger, gingko, ginseng, glucosamine

Question 27

Drugs that cause kyperkalemia?

Answer 27

1. RAAS inhibitors 2. Potassium sparing diuretics (amiloride, triamterene) 3. salt substitute, calcineurin inhibiotrs

Question 28

QT prolongationcan lead to ?

Answer 28

Torsades de pointes

Question 29

# q What are the ADRs asscoaited with CNS depression?

Answer 29

1. Somnolence 2. DZ 3. Confusion 4. Cognitive impairment 5. Altered consciousness 6. Falls

Question 30

What medications should not be taken together to avoid CNS depression?

Answer 30

1. Opioids 2. Benzos 3. Alcohol

Question 31

Drugs that cause ototoxicity?

Answer 31

1. Aminoglycosides 2. Cisplatin 3. Loops 4. Aspirin 5. Vancomycin

Question 32

Drugs that cause nephrotox?

Answer 32

1. Aminoglycosides, vanc, amphotericin B, polymixins 2. Cisplatin 3. CIs 4. Loops 5. NSAIDs 6. Contrast dyes (radiographic)

Question 33

Anticholinergic toxicity is moreconcerning for who?

Answer 33

Elderly

Question 34

Drugs that increase risk for orthostasis>

Answer 34

PDE5-I with CYP3A4 inhibotrs, Nitrates, or a-1 blockers