antiarrhythmic agents2

Question 1

is thyroid disease a CI for amiodorone?

what makes hypothyroidism so common with amiodorone?

Answer 1

not contraindicated

stops conversion of T4 to T3

Question 2

what causes hyperthyroidism in some pt’s taking amiodorone

Answer 2

amiodarone is composed of 37% iodine

Question 3

what are 3 CI’s with amiodorone

Answer 3

1. severe lung disease
2. liver disease
3. bradycardia

Question 4

what are the two major drug interactions with amiodorone?

what should be done with these drugs if amiodorone is started?

Answer 4

warfarin and digoxin

- cut there dose in half

Question 5

what should be ignored when trying to monitor amiodorone

Answer 5

plasma concentrations; meaningless

Question 6

what is inhibited by amiodorone leading to some drug interactions

Answer 6

CYP450s and P-glycoprotein

Question 7

what should be monitored with amiodorone? how often?

Answer 7

1. liver function tests
2. chest x-ray/ pulmonary function
3. thyroid function

Question 8

what study proved that dronedarone (multaq) taken by who were at risks for vascular events were at an increased risk for HF and stroke

Answer 8

PALLAS

Question 9

what case study proved dronedarone is less effective at maintaining sinus rhythm but incurred less thyroid, hepatic, pulmonary, neuro, skin and ocular toxicities than amiodorone

Answer 9

DIONYSOS

Question 10

what type III antiarrhythmic is is most common for causing adverse GI effects

Answer 10

amiodorone

Question 11

what should be monitored in every antiarrhythmic agent treatment

Answer 11

potassium, calcium, and magnesium

Question 12

what is the halr life of dronedarone

Answer 12

24 hours (much less than amiodorone)

Question 13

what is the most important CI for dronedarone

Answer 13

DO NOT USE IN HEART FAILURE

Question 14

what class is sotalol? why is this weird

Answer 14

class 3
it is a beta blocker, but it's antiarrhythmic MOA is much more related to it's Ca channel blockade

Question 15

at what CrCl is sotalol contraindicated

Answer 15

less than 40

Question 16

what type III antiarrhythmic is on restricted access program due to high incidence of torsades?

Answer 16

dofetilide

Question 17

what is a good 2nd line option for people who can’t take amiodorone

Answer 17

dofetilide

Question 18

what are two options for treating atrial fib in pts with HF?

Answer 18

amiodorone

dofetilide

Question 19

what are two important kinetic points with dofetilide

Answer 19

1. metabolized by 3A4

2. renal elimination for 80% of dose

Question 20

at what CrCl is dofetilide contraindicated

Answer 20

less than 20

Question 21

what are 2 things that dofetilide dosing is based on?

Answer 21

1. first dose is based on CrCl (renal function)

2. second and subsequent doses based on QTc interval (change in QT interval)

Question 22

what is the change in QTc interval cutoff indicating dose change of dofetilide

Answer 22

less then or equal to 15% QTc interval= continue dose

greater than 15% QTc interval = smaller dose

Question 23

what are CIs for dofetelide (other than drugs)

Answer 23

1. ClCr < 20
2. QTc baseline greater than 440 (prolonged QT interval)
3. QTc increases to more than 500 msec after 2nd dose

Question 24

what are the normal QT’s

Answer 24

less than 400

Question 25

what are some common drugs contraindicated with dofetilide?

Answer 25

1. hydrochlorothiazide 2. trimethoprim 3. cimetidine 4. ketoconazole

Question 26

any drug that does what two things is CI for dofetilide?

Answer 26

1. prolong QT interval | 2. CYP3A4 inhibitors

Question 27

what should b emonitored when taking dofitilide, at least every 3 months

Answer 27

1. serum creatinine 2. ECG (QT interval) 3. electrolytes