class 4 and 5 anti arrythmics

Question 1

class 4 name, effects, function and drugs

Answer 1

effects: L type voltage sensitive CCbs => decrease IC calciium-> DECREASING PHASE 0, AND 4 shortening AP duration, decline of plateau, decreasing SA and AV automaticity slows sinus rate, prolonging AV time-> increasing PQ and RR interval
drugs: verapamil, diltiazem

Question 2

verapamil, diltiazem

Answer 2

pk: high plasma protein binding inactivation of CYP3a4
i: angina, SVA, hypertension
AE: cardiac = brady cardia, AV block, HF
hypotension, headache, dizziness, peripheral edema, constipation
contraindication: wpw syndrome

Question 3

class 5 antiarrythmics

Answer 3

classified as others and include adenosine, Mg sulfate, digoxin, atropine

Question 4

adenosine

Answer 4

action: direct A1 r. -> enhance Ik ach -> hyperpol.
indirect action: Gi-> decrease cAMP-> decreasing ca influx -> decreasing SA,AV activity
pk: short duration, admin Iv bolus
AE: asystole, hypotension, bronchoconstriction, dyspnea (M3), headache, nausea, flushing
drug interaction: caffine & theophyllin -> inhibit action

Question 5

MG sulfate

Answer 5

action: Mg needed for ion tp =>slows automaticity of SA + prolong conduction time, admin via IV
i: torsades de pointes, digitalis intoxification

Question 6

digoxin

Answer 6

action: inhibit Na/K atpase, vagal stimulation -> inhibit AV conduction
admin: parenteral
i: Afib, pulse deficit, HF
AE: proarrythmogenic

Question 7

atropine:

Answer 7

i: 1st degree av block, brady cardia