Fcm Arrhythmia Drugs

Front 1

What is the ionic basis of cardiac electrical conduction and action potential propagation? ie What ions and when?

Back 1

SA and AV nodes: mostly Ca channels for depol, slow. myocardium: mostly Na channels, fast. K+ is inside and comes out for repolarization. Fewer channels or longer recovery time can generate arrhythmias.

Front 2

What is the Vaughan WIlliams anti-arrhythmic classification system?

Back 2

Class 1: Na+ channel blockers. 1A: intermediate. 1B: fast on-off. 1C: slow on-off. Class 2: beta-blockers. Class 3: K+ channel blockers. Class 4: Ca++ channel blockers. Extra: digoxin, adenosine, atropine.

Front 3

Class 1A drugs

Back 3

quinidine, procainamide, disopyramide. Na+ channel blockers.
--> slow phase 0 depol, longer AP, longer refractory period, slows conduction, decr reentry.
Used for: tachyarrhythmias (atrial, ventricular, A-V), maintain sinus rhythm after Afib/flutter cardioversion, prevent frequent V-tach.

Front 4

Quinidine

Back 4

Class 1A.
--> ACh block, incr AVN conduction, decr myocardium conduction.
works for arrhythmias caused by normal automaticity.
ADME: rapid abs, protein bound, placenta and breast milk, urine elim.
AE: exacerbates arrhythmias, N/V/D, cinchonism, etc.
INTAXN: CYP450, incr digoxin, phenytoin increases elim.

Front 5

Procainamide

Back 5

Class 1A. IV only. acts like quinidine.
Proc--> HV slowing. NAPA (metabolite) --> long QT & renal elim.
AE: exacerbates antiarrhythmias, flushing, N/V/D, etc.
Monitor: proc indicates metabolism (>10-12 is toxic), NAPA indicates renal clearance. Levels don't indicate function.

Front 6

Class 1B

Back 6

Lidocaine, Mexiletine, Phenytoin. shortens phase 3 depol, shorter AP. Bind open or inactivated Na+ channels, fast release, more effective in diseased myocardium. blocks depolarized or rapidly-driven tissues.

Front 7

Lidocaine

Back 7

Class 1B.
IV form, doesn't work for arrhythmias from normal automaticity. abolishes reentry. ONLY for ventricular arrhythmias.
ADME: big first-pass met (IV only), hep-elim.
AE: brady, hypoTN, dizziness, confusion, etc.
INTAXN:b-blockers, quinolones, phenytoin, propofol, St. John's Wort.
Monitor: >6 is toxic (seizures, agitation)

Front 8

Mexiletine

Back 8

Class 1B.
like lidocaine but po.
ADME: t1/2=12hrs. low first-pass met. CYP450 met.
AE: hypoTN, bad taste, N/V/D, liver enzymes, fatigue, etc.
INTAXN: chlorpromazine, quinolone, azoles, SSRIs, antacids, sodium barcabonate, acetazolamide incr mex, carbamezapine, phenobarbital decr mex.
Monitor: toxic >2mcg/mL. Liver enzymes, ANA, platelets.

Front 9

Phenytoin

Back 9

Class 1B-like anticonvulsant. like lidocaine. Not approved as an anti-arrhythmic and rarely used.

Front 10

Class 1C

Back 10

Flecainide, Propafenone.
most potent Na channel blocker, slow on-off. decrease rate of phase 0 upstroke.
Used for PVC, Paroxysmal SVT, Afib.
AE: depressing effects on heart-- use with caution., proarrhythmic, may incr mortality.

Front 11

Flecainide

Back 11

For refractory ventricular arrhythmias, negative inotrope, exacerbates CHF.
ADME: good abs, hep met, renal elim, t1/2= 7-22 hrs.
AE: rash, N/D, nervousness, tinnitus, etc.
INTAXN: protease inh, urinary alk agents incr flec, smoking and acidifying agents decr flec.
Monitor: vitals, renal and liver function.

Front 12

Propafenone

Back 12

broad-spectrum, some b-blocking activity.
ADME: high bioav, t1/2=8hrs, hep met, fast and slow metabolizers, first-pass met saturation.
AE: rash, N/V/D, blurred vision, etc.
INTAXN: enzyme inducer decrease blood levels, food may increase.

Front 13

Class II

Back 13

b-adrenergics. blocks symps, blocks pacemaker in SA node to decrease phase 4 depol (decr HR), inhibition in AV node decreases Ca++ and K+ levels (decr conduction)-- AV node is more sensitive.

Front 14

Generations of b-blockers

Back 14

1st gen: propanolol, nadolol, timolol-- nonselective, treats tachyarrhythmias caused by cats in exercise and emotions. doesn't prolong repol (used for long QT).
2nd gen: atenolol, metoprolol, acebutolol, bisoporlol, esmolol--pretty selective, only esmolol is antiarrhytmic.
3rd gen: labetolol, carvedilol-- also is a-ant, causes vasodilation

Front 15

b-blocker uses

Back 15

HTN (except esmolol and sotalol)
Post-MI prophylaxis: Decr sudden death due to arrhythmias, acute MI, angina, stable heart failure, arrhythmias
AE: bronchospasm, impotence, cold, neg inotropes, insomnia, depression

Front 16

Class III

Back 16

amiodarone, dofetilide, ibutilide, sotalol, dronedarone.
Block K+ channels.
--> longer plateau and longer repol, increased refractory period, decreased reentry, increased TdP and early afterdepolarization. reverse use-dependency (works best at slow rates), no effect on conduction.

Front 17

Amiodarone

Back 17

Class III.
Most frequently used.
-->has effects of all classes: longer refractory period, slows pacemaker (Na channels, blocks a- and b-adrenergics (hypoTN, neg inotrope), AV nodal block (but low TdP)
ADME: hep met, t1/2 = 50d. peak effects w/in 1 wk to 5 mo.
Use for: 1. unstable V-tach or V-fib. 2. recurrenent V-tach, esp with MI or CHF. 3. prevent recurrent paroxymal A-fib/flutter.
AE: everything. hypoTN, CNS effects, derm, endocrine, hyper/hypothyroid, GI, liver enzymes, ocular, pneumonia.
INTAXN: any drug that incr QT. also enhances digoxin and warfarin effects.
Monitor: LFTs, TFTs, PFTs (or CXR), eyes, ECG.

Front 18

Dofetilide

Back 18

Class III.
incr QT b/c incr refractory period, only for ppl in a certain program.
Use: convert Afib/flutter to NSR and maintain NSR. Can be for V-tach.
ADME: good bioav, renal elim, low CYP3A4.
Use if QTc < 440 msec, correct K+ and Mg+, no interacting meds, initial dose is based on creatinine clearance, pts monitored for first 72 hrs. Then if QT prolongs >15%, readjust. Stop if QT > 500 msec.
AE: CNS, CV (some TdP, esp MI/CHF), rash, back pain, dyspnea).
INTAXN: contraindications are some drugs, HR<50, hypoMg, hypoK, creatine cl < 20 ml/min.
Monitor: renal function, QT, electrolytes (want K>4, Mg>2).

Front 19

Ibutilide

Back 19

Class III.
IV only.
Use: new onset afib/flutter (<90 d) (to convert it). Monitor through administration (may prolong QTc and TdP). Correct electrolytes before administration.

Front 20

Sotalol

Back 20

Class III and non-selective b-blocking activity.
Use: life-threatening ventricular tachycardia, maintain NSR for symptomatic afib/flutter.
AE: of both class II and III.

Front 21

Dronedarone

Back 21

Similar to amiodarone w/o thyroid or pulm toxicities.

Front 22

Class IV

Back 22

Verapimil and Diltiazem.
Ca++ channel blockers. decrease phase 4 spontaneous depol, slows AVN conduction, more effective against voltage-sensitive, binds only to open channels, use-dependent (better with fast HR).
Use: reentrant SVT, to decr HR in Afib/flutter, HTN.

Front 23

Diltiazem

Back 23

Class IV
ADME: rapid abs, large first pass, IV loading dose. t1/2= 3-4hrs.
AE: edema, flushing, pain, heart block, gout, etc.

Front 24

Verapamil

Back 24

Class IV
ADME: extensive first-pass.
AE: periph edema, givingival hyperplasia, constipation, bradycardia, CHF, hypotension, ...

Front 25

Adenosine (ATP)

Back 25

decreases AV node automaticity
Use: first line to convert narrow complex paroxysmal SVT to NSR.
AE: transient, flushing, headache, excessive AV/SA suppression, chest pain.
Shortens atrial and ventricular refractory period. Purk: longer refractory period, slower conduction. increased contractility.
AE: heart block, blurred vision, ataxia, N/V, confusion.
ADME: caution w/ loading dose (wait for distribution), renal elmin, t1/2 > 24 hrs

Front 26

(Digoxin)

Back 26

for Afib with CHF. Narrow therapeutic window, renal elim.
AE: ECG abnormalities. Lots of drug interactions.
Monitor: check levels, look for AEs.
toxicity --> conduction disorder, impulse formation problems. Use atropine for bradycardia, transvenous temp pacemaker, lidocaine or phenytoin for ventricular arrhythmias.

Front 27

Use for Class IA drugs

Back 27

1. treat atrial, AV junctional and ventricular tachyarrhythmias.
2. maintain NSR after Afib/flutter cardioversion.
3. prevent frequent ventricular tachyarrhythmia.

Front 28

Use for Class IB drugs

Back 28

More effective with diseased myocardium.
*Ventricular arrhythmias.

Front 29

Use for Class IC drugs

Back 29

1. PVC
2. paroxysmal SVT
3. A-fib
(may increase mortality)

Front 30

Use for Class II anti-arrhytmics

Back 30

post-MI prophylaxis of sudden death due to arrhythmias, arrhythmias

Front 31

Use for Class III

Back 31

(approved for VT, but it's the most effective AF drug we have.)
Convert Afib to NSR and maintain NSR after conversion.
V-tach.

Front 32

Use for Class IV drugs

Back 32

1. Reentrant SVT
2. reduce HR in Afib/flutter
3. HTN

Front 33

Use for Adenosine

Back 33

converting narrow complex paroxysmal SVT to NSR

Front 34

(Use for digoxin)

Back 34

AF in CHF