29 April wk7-E

Question 1

What is a rare but significant SE of statin therapy?

Answer 1

Myopathy: muscle pain and elevated serum CK

Question 2

What cytochrome enzyme is at the heart of the interaction between some macrolides and statins?

Answer 2

CYP 3A4
Erythromycin inhibits this and statins are metabolized by it
Co-administration causes high levels of statins leading to toxicity including myopathy

Question 3

CYP 450 inducers

Answer 3

Carbamazepine, Phenobarbital, Phenytoin, Rifampin, Griseofulvin

Question 4

CYP 450 inhibitors

Answer 4

Cimetidine, Ciprofloxacin, Erythromycin, Azole antifungals, Grapefruit juice, Isoniazid, Ritonavir (protease inhibitors)

Question 5

Carbamazepine and P450

Answer 5

inducer

Question 6

Grapefruit juice and P450

Answer 6

inhibitor

Question 7

Isoniazid and P450

Answer 7

inhibitor

Question 8

Griseofulvin and P450

Answer 8

inducer

Question 9

Ritonavir and P450

Answer 9

inhibitor

Question 10

Phenobarbitol and P450

Answer 10

inducer

Question 11

Phenytoin and P450

Answer 11

inducer

Question 12

Erythromycin and P450

Answer 12

inhibitor

Question 13

Cimetidine and P450

Answer 13

inhibtor

Question 14

Ciprofloxacin and P450

Answer 14

inhibitor

Question 15

Rifampin and P450

Answer 15

inducer

Question 16

Azole antifungals and P450

Answer 16

inhibitor

Question 17

Which macrolides affect CYP 3A4 and which do not?

Answer 17

Erythromycin and Clarithromycin inhibit

Azithromycin does not

Question 18

Inhibitors of CYP 3A4

Answer 18

Erythromycin, Ketoconazole, Cyclosporine, HIV protease inhibitors, Grapefruit Juice

Question 19

If patient is on a statin, what is a common drug interaction and which statin is best to avoid this?

Answer 19

Statins are metabolized by CYP 3A4
Interactions with drugs inhibiting it:
Erythromycin, Ketoconazole, Cyclosporine, HIV protease inhibitors, Grapefruit Juice
Best statin to avoid this is Pravastatin because it is metabolized by another enzyme

Question 20

How does doxorubicin create cardio-toxicity?

Answer 20

Creates free-radicals that damage the heart leading to dilated cardiomyopathy

Question 21

Best method of preventing doxorubicin cardiomyopathy

Answer 21

Dexrazoxane

Iron-chelating agent that prevents formation of free radicals

Question 22

What is the general treatment approach for sustained ventricular arrhythmias after and MI?

Answer 22

Amiodarone first
If needed, Lidocaine or another class IB antiarrhythmic agent

Question 23

Amiodarone

Answer 23

Class III antiarrhythmic agent, blocks K+ channels prolonging AP duration and QT interval

Question 24

MOA of Digoxin and uses

Answer 24

Enhances vagal tone on the heart and slows conduction through AV node
Useful for arrhythmias originating above AV node but not for ventricular arrythmias

Question 25

Which of the antiarrhythmic agents is best suited for treating an abnormal rhythm originating from ischemic or damaged myocardium in the ventricle?

Answer 25

Class IB drugs because they bind preferentially to inactive channels whereas class IA drugs bind to open Na channels

Question 26

Clonidine is generally used for HTN, but can also be used for what?

Answer 26

ADHD in patients who failed other stimulant therapy

Question 27

What features help identify a Tourette's tic from myoclonus?

Answer 27

Tics can be temporarily or partially suppressed and they are preceded by an urge to move. Myoclonus has neither feature.

Question 28

What is an essential tremor and how is it treated?

Answer 28

Intention tremor often of both hands appearing in middle adulthood Treated with Propranolol

Question 29

Fluphenazine

Answer 29

Dopamine antagonist that can treat Tourette's

Question 30

Alteplase, Tenecteplase

Answer 30

Fibrinolytics used to treat ACS to lyse clots Bind to Fibrin in the clot and activate Plasminogen to Plasmin to lyse the Fibrin clot Common SE is hemorrhage

Question 31

What is a classic sign of aortic dissection?

Answer 31

Widened mediastinum on x-ray

Question 32

What vessels are most affected by NO? Why does this help angina?

Answer 32

Large veins | Helps angina by redistributing blood to the veins and decreases preload on the heart and thereby decreases O2 demand

Question 33

Why are ACEI's protective for the kidneys in DM?

Answer 33

DM leads to increased glomerular pressures leading to damage over time. ACEI's dilate the efferent arteriole decreasing filtering pressures and protecting the glomeruli. ARB's have a similar effect

Question 34

As DA administration goes from low to high dose, what receptors are activated and what effects?

Answer 34

Low: D1–vaso-D in renal and splanchnic vasculature Med: B1–increased cardiac effects High: alpha1–vasoconstriction to renal and visceral vasculature

Question 35

Dihydroergotamine

Answer 35

Treat acute migraine | May induce spastic angina by stimulating alpha and serotonin receptors

Question 36

Phentolamine

Answer 36

Non-selective alpha blocker

Question 37

Possible triggers of Prinzmetal's angina?

Answer 37

Tobacco, cocaine, amphetamines, dihydroergotamine, statins

Question 38

Sodium Nitroprusside

Answer 38

IV vasodilator

Question 39

MOA for Nitrates

Answer 39

Converted in endothelial cells to NO that diffuses into SmM cells and activates guanylate cyclase to produce cGMP. cGMP reduces intracellular Ca reducing action of myosin light chain kinase and dephosphorylating myosin light chain causing muscle relaxation and vasodilation

Question 40

Describe events leading to muscle contraction starting with Ca release from ER.

Answer 40

Ca binds Troponin on Actin and moves Tropomyosin to reveal binding sites Myosin binds Actin when it hydrolyzes ATP to ADP + P Power Stroke after releasing ADP+P Myosin remains attached until ATP binds

Question 41

Indications for benzodiazepine use

Answer 41

Anxiolytic, sedation, anticonvulsant, muscle relaxant

Question 42

Chlorpheniramine

Answer 42

1st gen antihistamine | Lots of SE's because not only blocks H receptors but many others

Question 43

Benzos should be avoided in conjunction with?

Answer 43

Alcohol, barbiturates, neuroleptics, 1st gen antihistamines

Question 44

Name 1st gen antihistamines and why they are so sedating

Answer 44

``` Diphenhydramine Promethazine Hydroxyzine Chlorpheniramine 1st gen cross BBB and accumulate in CNS blocking H receptors and this causes sedation ```

Question 45

Bad SE of carbamazepine

Answer 45

Agranulocytosis or aplastic anemia

Question 46

MOA of Gabapentin

Answer 46

Blocks presynaptic Ca channels to reduce release of NT's to treat seizures

Question 47

What seizure drug blocks PRESYNAPTIC Na channels?

Answer 47

Phenytoin

Question 48

Are GABA receptors pre or post synaptic?

Answer 48

Post synaptic

Question 49

When should you suspect malignant hyperthermia syndrome and what is the mechanism?

Answer 49

Patient recently under general anesthesia with an inhaled anesthetic presenting with fever and muscle rigidity, myoglobinemia, HTN, hyperkalemia, and elevated CK Inherited predisposition where ryanodine receptors release too much Ca upon stimulation by anesthetics leading to rapid reuptake and use of ATP in sarcoplasmic reticulum leading to heat production and eventually damage to muscle and rhabdomyolysis Dantrolene (muscle relaxant) treats by decreasing Ca release