Drug Interactions

Question 1

Name the 4 strong inducers of CYP 3A4. (PPFC)

Answer 1

Phenytoin, Fosphenytoin, Carbamezapine, phenobarbital

Question 2

How does dexamethasone affect methadone?

Answer 2

Decrease efficacy of methadone.

Question 3

Cipro affect on methadone/fentanyl? Preferred floxacin abx?

Answer 3

Cipro inhibits CYP3A4 causing increased levels of methadone/fentanyl. Preferred Levaquin.

Question 4

Effects of Erythro and clarithromycin? Alt mycin abx?

Answer 4

Inhibit CYP3A4, causing increase drug levels and potency. Consider Azithromycin.

Question 5

Name the -Azoles with sig drug interactions? What is effect on CYP3A4?

Answer 5

Fluconazole, voriconazole, posaconazole. Inhibit CYP3A4.

Question 6

Adverse effect to watch out for Buproprion?

Answer 6

Can lower seizure threshold

Question 7

St. Johns Wort indication? Effect on CYP? Important AE?

Answer 7

Tx for depression, Inducer, can cause serotonin syndrome.

Question 8

Grapefruit effect on CYP? What meds does it affect?

Answer 8

Inhibit, increase doses of statins

Question 9

What is 1st line tx for opioid induced itching?

Answer 9

Diphenhydramine (Benadryl)

Question 10

What age should pts taking TCA be screened with EKG?

Answer 10

40 years or older

Question 11

True/false. Respiratory acidosis increases effect of opioids?

Answer 11

False, Resp Alkalosis can increase transmission to cross BBB.

Question 12

What is Rifampin effect on CYP?

Answer 12

Inducer, increase breakdown of meds making less effective.

Question 13

Effect of TCA on methadone?

Answer 13

Increase methadone’s effect

Question 14

What to worry about when starting Meperidine?

Answer 14

It can cause seizures due to its metabolite.

Question 15

What is one advantage of clonidine?

Answer 15

It can decrease postoperative oxygen consumption.

Question 16

Which class of meds should be used cautiously if pt also taking L-tryptophan?

Answer 16

SSRI can cause serotonin syndrome.

Question 17

What meds should be avoided with buprenorphine?

Answer 17

Antiarrhythmics

Question 18

Weird SE of glucocorticoids?

Answer 18

Hiccups.

Question 19

What herbal medicine has some effect in helping chemotherapy induced fatigue? What meds should be used cautiously with this herb?

Answer 19

American Ginseng, interacts with anticoagulation meds

Question 20

What is indication for Kava-Kava?

Answer 20

Anxiety, possible benefit.

Question 21

What is indication for Ginkgo biloba?

Answer 21

Dementia, but not shown to be beneficial.

Question 22

What are some important SE of megace? 3

Answer 22

VTE, adrenal insufficiency, male androgen deficiency

Question 23

What 3 chemo drugs are highest emetogenic?

Answer 23

Cisplatin, cyclophosphamide, dacarbazine.

Question 24

Of the 3 which meds can cause sexual dysfunction and decreased libido? Buspar, Buproprion, opioids?

Answer 24

Opioids.

Question 25

What are the 4 "A's" when initiating chronic opioids?

Answer 25

Analgesia, Adverse effects, Aberrant behaviors and Activity.

Question 26

True/False. | Methylnaltrexone crosses the blood brain barrier?

Answer 26

False, it is quaternary structure so it doesn't.

Question 27

Which NSAID has greatest risk of CV risk?

Answer 27

Diclofenac.

Question 28

Olanzapine blocks what receptors for nausea?

Answer 28

serotonin, histamine, dopamine, and acetylcholine.

Question 29

What drug is 6-MAM a metabolite of?

Answer 29

Specific to heroin.

Question 30

Which opioid is least likely to cause bradycardia?

Answer 30

Meperidine, it can cause tachycardia.

Question 31

Which TCA has the least SE?

Answer 31

Nortriptyline.

Question 32

What drug metabolizes into meprobamate?

Answer 32

Carisoprodol (soma), used as antispasmodic

Question 33

In neonates, how are opioids different compared to adults?

Answer 33

Neonates have decreased clearance leading to prolong half life of opioids.

Question 34

Which NSAIDs are available parenterally?

Answer 34

Meloxicam, ibuprofen, ketorolac, diclofenac

Question 35

True/False about lidocaine patch? 1. Caution in use with antiarrhythmics/local anesthetic? 2. Needs dose escalation and tolerance builds quickly? 3. Safe to use in severe hepatic disease and works quickly?

Answer 35

1. True 2. False 3. False

Question 36

Nortryptiline and desipramine are what class of of TCA?

Answer 36

Secondary amine and have more favorable SE profile/ less anticholinergic effects.

Question 37

Linezolid has odd MOA, what is MOA and can lead to what condition?

Answer 37

MOA-inhibitor, leads to serotonin syndrome with other serotonin agents.

Question 38

Drugs/classes that can cause serotonin syndrome? | 15 drugs

Answer 38

SSRI, MAOi, meperidine, fentanyl, TCA, triptans, carbamazepine, valproic acid, tramadol, lithium, St. Johns wort, ritonavir, metaclopramide, zofran.

Question 39

What is oral to intrathecal ratio conversion of morphine?

Answer 39

1 intrathecal : 10 epidural. 1 epidural : 10 IV 1 IV : 3 mg Oral

Question 40

What SE should you be worried about when starting baclofen?

Answer 40

lower seizure threshold

Question 41

What is most common SE of modafinil (provigil)?

Answer 41

Headaches

Question 42

What is MOA of cyclobenzaprine? What other drug class is it similar to?

Answer 42

Inhibits norepinephrine reuptake and serotonergic reuptake. Similar to 1st gen TCA.

Question 43

Which SSRI can be stopped abruptly due to it's long half life?

Answer 43

Fluoxetine.

Question 44

True/false. Meperidine is not affected by renal insufficiency? Meperidine has an active metabolite?

Answer 44

False. AKI increases bioavailability | True, it can lead to seizures/serotonin syndrome

Question 45

True/False. 1. Methylnaltrexone induces opioid withdrawal? 2. What is absolute contraindication to starting methylnaltrexone?

Answer 45

1. False | 2. Bowel obstruction, it can cause bowel perf.

Question 46

What common SE can be seen in Tramadol?

Answer 46

Hypoglycemia