Antiarrhythmics Flashcards
How do you identify A fib?
irregularly irregular rhythm, NO P WAVES
Rate of A fib vs A flutter
A fib: usually 100-140 bpm
A flutter: >140 bpm
What are class I antiarrhythmics
Na channel blockers
Na channel blocker examples most often used (according to Kim’s notes)
Flecanide (tambacor)
Rythmol (propafenone)
what are class II antiarrhythmics
beta blockers
beta blocker examples
lopressor/Metoprolol - go to agent
Carvedilol/Coreg
atenolol (Tenormin)
what are class III antiarrhythmics
potassium channel blockers
potassium channel blocker examples
dofetilide (Tikosyn)
sotalol (beta pace)
amiodarone
dronedarone (Multaq)
special considerations with potassium channel blockers
pt must be admitted to hospital for observation when initiating medication b/c can cause QT prolongation
potassium channel blocker CI
- renal dysfunction
2. many drug interactions (other drugs that cause QT prolongation)
Special considerations for amiodarone
very effective but lots of bad side effects
only use short-term or in elderly
What do you have to test when giving amiodarone
- thyroid
- PFTs
- Liver function
what are class IV antiarrhythmics
non-dihydropyridine calcium channel blockers
non-dihydropyridine calcium channel blocker examples
verapamil (calan)
diltiazem (cardizem)
Causes of arrhythmia
- Coronary artery disease/MI
- altered impulse formation (ectopic foci, changes in automaticity)
- altered impulse conduction (block of conduction)
- heart failure
- drug/medication induced
- electrolyte disturbance
Three R’s of arrhythmia management
- rate control
- rhythm control
- risk of stroke/need for anticoagulation
Sodium Channel Blockers MOA
block Na channels –> slower conduction of AP
1A - moderate slowing
1B - minimal slowing
1C - maximal slowing
Subclass 1A of Sodium Channel Blockers indications
atrial and ventricular arrhythmias
Subclass 1A of Sodium Channel Blockers examples
procainamide
quinidine
Risk factors for A fib
HTN, DM, obesity, sleep apnea
paroxysmal A fib
goes about 48 hours then stops by itself
Sodium channel blockers classes
1A, 1B, 1C
Sodium channel blockers MOA
slow conduction –> influence QT interval
Where is quinidine initiated
hospital setting b/c can prolong QT interval, risk for ventricular tachycardia
Quinidine S/E
severe GI upset, diarrhea
Quinidine drug interactions
digoxin
warfarin
1B Sodium channel blockers indications
ventricular arrhythmias
1B Sodium channel blockers examples and route of administration
Lidocaine (Xylocaine) - IV
Mexiletine - oral
Mexiletine initiation setting
often in hospital but can be outpatient
Mexiletine S/E
Tremor, seizure, N/V
1C Sodium channel blockers MOA
prolongs the AV node refractory period
1C Sodium channel blockers indications
a fib
1C Sodium channel blockers CIs
CAD, MI, LV dysfunction, ischemic arrhythmia, decreased EF
1C Sodium channel blockers examples
propafenone (rhythmol)
flecainide (tambocor) - will see a lot!
Flecainide initiation setting
outpatient
monitoring when giving flecainide
exercise stress test w/o imaging 1-2 weeks after initiation to evaluate possible QRS widening
what must you always prescribe with flecainide
a rate controlling agent
Flecainide S/E
dizziness, headache, blurred vision
Beta Blockers MOA
decrease automaticity, slow conduction velocity, prolongs refractory period (depresses AV node)
metoprolol forms and differences
Metoprolol tartrate: short acting, dosed BID (don’t use if LV dysfunction)
Metoprolol succinate: long acting, dosed QD
Beta Blocker side effects
- fatigue
- GI disturbances
- insomnia, nightmares
- lethargy
- erectile dysfunction
- bradycardia
Potassium Channel Blockers MOA
blocks potassium channels in phase 3 of AP –> slows efflux of K back out of myocyte –> lengthens plateau phase
Dofetilide (Tikosyn) initiation setting
hospital 72 hour admission (continuous telemetry, regular ECG, daily BMP)
Dofetilide (Tikosyn) indications
a fib
Dofetilide (Tikosyn) S/E
QT prolongation
Torsades
Dofetilide (Tikosyn) drug interactions
thiazide diuretics
downside to Dofetilide (Tikosyn)
have to monitor ECG and BMP every 6 months
sotalol initiation setting
hospital 72 hour admission - daily ECG, BMP, continuous telemetry
sotalol indications
atrial and ventricular arrhythmias
amiodarone indications
most effective of antiarrhythmic drugs
amiodarone s/e
liver, thyroid, GI, skin, CNS (tremor), visual (corneal deposits, optic neuropathy), photosensitivity, pulmonary fibrosis
What do you have to get before starting amiodarone
baseline thyroid labs, LFTs, PFTs w/ DLCO
what do you have to monitor when taking amiodarone
LFTs, TSH, CXR, PFTs every 6 months
how long does it take amiodarone to leave the body
6 weeks
amiodarone cardiac SE
bradycardia
heart block
Hypotension
amiodarone noncardiac SE
pulmonary fibrosis thyroid dysfunction (MC) blue skin nausea constipation anorexia liver damage
what is dronedarone / multaq and where is it initiated
modified amiodarone molecule (deionization) - can be started outpatient
dronedarone / multaq CIs
hx of heart failure!!!! or permanent AF
calcium channel blockers MOA
blocks calcium channels in phase 0 of AP –> slower pacemaker in SA node, longer refractory period in AV node
diltiazem/cardizem is often given for
rapid A fib in ER
diltiazem/cardizem SE
headache, dizziness, bradycardia
important things to remember when giving diltiazem/cardizem
take thorough history
monitor labs q6 months - serum electrolytes, renal function
routine monitoring of renal and hepatic function
ECG every 6-12 mo
which version of metoprolol do you give for heart failure
long acting version - succinate
what is MC beta blocker used for CHF and A fib
carvedilol
carvedilol vs. metoprolol
carvedilol often well tolerated but not as strong for limiting rate as metoprolol
CI for atenolol
poor kidney function
What do you need to watch for with tikosyn/dofetilide
hypokalemia, magnesium labs
CI for tikosyn/dofetilide
kidney dysfunction - could build up and cause QT prolongation
drug interactions with tikosyn
A LOT
zofran, tagamet, etc.
CI for sotalol
kidney impairment - will build up and cause QT prolongation, bradycardia
dosing for amiodarone
have to take higher dose initially to build it up in the system then gradually drop down to lower dose over 1 month to reach maintenance dose
amiodarone uses by age
give to old people
young: used peri-procedurally for ablation, ideally <12 month, bridge therapy
sign of amiodarone toxicity
SOB + regular rhythm
warfarin indications
prophylaxis for DVT, PE, post-MI, mechanical valves!
warfarin dosing
must be adjusted to each pt’s metabolism, INR response
what does CHADS2-VASc stand for
CHF HTN Age 75+ (2) DM Prior stroke or TIA (2) vascular disease Age 65-74 Sex category - female
scoring for CHADS2-VASc
2+ for men
3+ for women
what does HAS-BLED stand for
HTN Abnormal renal and liver function (1 each) Stoke Bleeding Labile INR Elderly (>65) Drugs or alcohol (1 each)
HAS-BLED score
3+ = high risk
oral anticoagulants
- vitamin K antagonist
- direct thrombin inhibitors
- factor Xa inhibitors
vitamin K antagonist example
warfarin
direct thrombin inhibitors example
dabigatran / pradaxa
factor Xa inhibitor examples
rivaroxiban / xarelto
apixaban / eliquis
endoxaban / savaysa
how long does it take warfarin to become effective
48-72 hours
DOAC indications
prevention of thromboembolism in non-valvular A fib
treatment of DVT/PE
a fib
DOAC examples
pradaxa
xarelto
eliquis
savaysa
DOAC with most indications and most dosages available
xarelto
DOAC CIs
active pathological bleeding known hypersensitivity mechanical prosthetic heart valves severe renal dysfunction severe hepatic impairment P-gp and strong CYP34A inhibitors or inducers
reversal agent for warfarin and how fast does it work
phytonadione (vitamin k), 12-24 hours
fresh frozen plasma
prothrombin complex concentrate
reversal agent for pradaxa
idarucizumab
what is triple therapy for a fib
warfarin, aspirin, clopidogrel
goes INR is 2-2.5
antiplatelets vs. anticoagulants (the ones we talked about)
antiplatelets for artery things
anticoagulants for venous things
who is eliquis really good for?
patients >80, also renal dysfunction
special consideration for xarelto
requires protein for absorption (Take with biggest meal of day at consistent time)
when do DOACs become effective after given
2 hours after dosing
reversal agent for Xarelto and eliquis
andexxa