K+ and Ca2+ Channel Blockers--Nordgren

Question 1

What is the function of Class III Drugs?

Answer 1

K⁺ blockers

prolong repolarization

K⁺ responsible for repolarizing AP

Question 2

What type of arrhthmia are K⁺ channel blockers best for?

Answer 2

reentry

Question 3

Most important adverse effect of amiodarone

Answer 3

dose-related pulmonary toxicity

Question 4

What are Class IV antiarrythmatic drugs?

Answer 4

Ca²⁺ channel (L-type) blockers

Question 5

What type of Ca²⁺ channels do class IV drugs affect?

Answer 5

L-type

Question 6

What are the 2 subtypes of Ca²⁺ channel blockers?

Answer 6

dihydropyridines (sm muscle)

non-dihydropyridines

Question 7

Dihydropyridines are in what general class?

what do they function to do?

Answer 7

Class IV: Ca2+ channel blockers

act on sm. muscle

decreased contractility of sm. muscle

Question 8

Non-dihydropyridines are in what general class?

what is their function?

Answer 8

class IV: Ca2+ channel blockers

act specifically on cardiac cells

Question 9

Non-dihydropyridines act on cardiac tissue how?

Answer 9

myocytes: decreases Ca2+ buffering of repolarization, decreasing refractory period

nodal cells: decreases ability to self-generate AP, prolongs refractory period –> decrease heart rate

Question 10

MOA: Adenosine

Answer 10

activation of K⁺ channels and inhibition of L-type Ca²⁺ channels

leads to hyperpolarization of cardiac myocytes

suppresses AV conduction and increases AV refractory period

Question 11

What is adenosine used for?

Answer 11

supraventricular tachycardias