Class III Antiarrhythmics
K+ Channel Blockers, Phase 3
Special populations: contraceptive recommended
Amiodarone (Nextrone, Dofetilide (Tikosyn) Ibutilide (Corvert)
Pacerone) Sotalol (Betapace)
Dronedarone (Multaq)
- Ventricular arrhythmias - a-fib/flutter
(Vfib, pulseless VT, - A-fib/flutter - A-fib/flutter
- A-fib (paroxysmal or - pharmacologic
Monomorphic VT) - sinus rhythm maintenance - pharmacologic cardioversion
persistent) cardioversion
- A-fib (off label) preferred - ventricular arrhythmias - maintenance sinus - NEVER used for
w/structural heart disease maintenance
rhythm
Tablet,
IV, Tablet IV,
Tablet Capsule IV infusion
Drug Interactions: Oral
- Additive bradycardia solution
(non-DHP Ca channel MOA:
MOA: MOA:
blockers, beta - inhibits Na and K MOA:
- Inhibits adrenergic - Beta blocker containing MOA: - Prolongs AP duration and
stimulation (blocks blockers, digoxin, channels, prolongation of
AP and refractory period both beta-adrenoreceptor - blockade of cardiac ion inc atrial/ventricular
alpha/beta properties), clonidine, blocking (vaughn williams
affects Na, K, and Ca in myocardial tissue w/o channel carrying rapid refractoriness by
dexmedetomidine) reverse-use dependent class II) and cardiac AP
channels. Prolongs AP component of the activating slow inward Na
- CYP inhibitor of many effects duration prolongation (VW delayed rectifier K
and refractory period in class III) properties current
myocardial tissue. drugs - Dec AV conduction and current
SA function by inhibiting - beta 1 and beta 2 blocking - delays repolarization by
- dec AV conduction and - increases conc: - inc monophasic AP
Ca channels and beta 1 activity (esp low doses25 inhibiting rapid
SA function - warfarin, digoxin, mg/day) duration due to delayed
- inhibits peripheral receptor activity component of delayed
lovastatin, simvastatin - inhibits alpha receptor - blocks K channels (high repolarization
conversion of T4 to T3 Dosing: rectifier K current
mediated inc in BP doses, oral >160 mg/day)
Dosing: Dosing: - renal adj CrCl < 60 Dosing:
- Do not give w/Sofosbuvir - Metabolism: Hepatic 3A4
substrate - Oral C/I CrCl<40 - weight based
due to bradycardia - IV: adj in CrCl<90
BBW: - >60 kg, 1mg over 10 min
- IV followed by oral - may use loading dose
therapy - Increased risk of HF,
stroke, death
C/I:
- Hypersensitivity
C/I: C/I:
C/I: - long QT syndromes
C/I: - Hypersensitivty - hypersensitivity
- permanent A-fib - baseline QT interval
- SSS, 2nd/3rd Deg AV - bronchial asthma/ SE:
- symptomatic HF or QTc >440 (500 if
Block bronchospastic - V Tach
- Toxicity related to ventricular
- bradycardia leading to amiodarone use conditions - QTc prolongation
conduction probs)
syncope w/o pacemaker - 2/3rd deg AV block or SSS - sinus brady <50 bpm - headache
- severe renal
- cardiogenic shock w/o pacemaker - 2/3rd deg AV block BBW:
impairment CrCl <20
- Preexcited a-fib/flutter - bradycardia <50 bpm - long QT syndromes - Life threatening
- use w/ cimetidine,
- hypersensitivity to - use w erythromycin or - cardiogenic shock arrhythmias
CYP3A4 inhibitors dolutegravir, HCTZ,
drug/iodine - decompensated HF - appropriate treatment
- use w drugs/herbs that itraconazole,
- SSS enviornment (prevent
prolong QT ketoconazole,
- Serum K <4 meQ conversion from
- QTc >500msec PR >280 megestrol,
- QTc interval >450 in maintaining sinus
- severe hepatic impairment prochlorperazine,
S.E: a-fib/flutter rhythm)
trimethoprim,
- bradycardia, verapamil, biktarvy
BBW: hypotension (inhibit renal
- life-threatening - AV block Monitoring: secretion)
arrhythmia - Qtc prolongation - ECG/HR/BP/rhythm
- acute hepatotoxicity S.E: - S/s of new or worsening Monitoring:
- hepatotoxicity Monitoring:
- pulmonary toxicity - Hepatotoxicity HF, pulmonary tox, liver BBW: - SCr, CrCl
- pulmonary toxicity - electrolytes (K, Mg)
- photosensitivity, rash, - QTc prolongation injury - Life threatening - Mg and K
- worsening arrhythmias - continuous ECG for at
SJS/TENs (rare) - pulmonary toxicity - serum K and Mg proarrhythmia - HR/BP SE:
Monitoring: least 4 hours
- blue-gray skin - heart failure - serum liver enzymes, Warnings: - ECG (PR/OTc - Headache
- ECG/BP/HR
- thyroid effects - increased SCr bilirubin - bronchospasm interval esp w/ IV) - V-tach (torsades)
- CXR/pulm function tests
- cornal microdeposits - bradycardia - verify pregnancy status - HF (initiation/titration) - Serum glucose (DM) BBW:
- LFTs and thyroid function
- peripheral neurop, - asthenia prior to use - renal impairment - s/s HF - Arrhythmias
- serum K and mg
tremor, dizziness (CNS) SE: Monitoring:
- Bradycardia - ECG (QTc)
- dizziness - SCr
- palpitations - Serum K and Mg
- fatigue
- dyspnea
K+ Channel Blockers, Phase 3
Special populations: contraceptive recommended
Amiodarone (Nextrone, Dofetilide (Tikosyn) Ibutilide (Corvert)
Pacerone) Sotalol (Betapace)
Dronedarone (Multaq)
- Ventricular arrhythmias - a-fib/flutter
(Vfib, pulseless VT, - A-fib/flutter - A-fib/flutter
- A-fib (paroxysmal or - pharmacologic
Monomorphic VT) - sinus rhythm maintenance - pharmacologic cardioversion
persistent) cardioversion
- A-fib (off label) preferred - ventricular arrhythmias - maintenance sinus - NEVER used for
w/structural heart disease maintenance
rhythm
Tablet,
IV, Tablet IV,
Tablet Capsule IV infusion
Drug Interactions: Oral
- Additive bradycardia solution
(non-DHP Ca channel MOA:
MOA: MOA:
blockers, beta - inhibits Na and K MOA:
- Inhibits adrenergic - Beta blocker containing MOA: - Prolongs AP duration and
stimulation (blocks blockers, digoxin, channels, prolongation of
AP and refractory period both beta-adrenoreceptor - blockade of cardiac ion inc atrial/ventricular
alpha/beta properties), clonidine, blocking (vaughn williams
affects Na, K, and Ca in myocardial tissue w/o channel carrying rapid refractoriness by
dexmedetomidine) reverse-use dependent class II) and cardiac AP
channels. Prolongs AP component of the activating slow inward Na
- CYP inhibitor of many effects duration prolongation (VW delayed rectifier K
and refractory period in class III) properties current
myocardial tissue. drugs - Dec AV conduction and current
SA function by inhibiting - beta 1 and beta 2 blocking - delays repolarization by
- dec AV conduction and - increases conc: - inc monophasic AP
Ca channels and beta 1 activity (esp low doses25 inhibiting rapid
SA function - warfarin, digoxin, mg/day) duration due to delayed
- inhibits peripheral receptor activity component of delayed
lovastatin, simvastatin - inhibits alpha receptor - blocks K channels (high repolarization
conversion of T4 to T3 Dosing: rectifier K current
mediated inc in BP doses, oral >160 mg/day)
Dosing: Dosing: - renal adj CrCl < 60 Dosing:
- Do not give w/Sofosbuvir - Metabolism: Hepatic 3A4
substrate - Oral C/I CrCl<40 - weight based
due to bradycardia - IV: adj in CrCl<90
BBW: - >60 kg, 1mg over 10 min
- IV followed by oral - may use loading dose
therapy - Increased risk of HF,
stroke, death
C/I:
- Hypersensitivity
C/I: C/I:
C/I: - long QT syndromes
C/I: - Hypersensitivty - hypersensitivity
- permanent A-fib - baseline QT interval
- SSS, 2nd/3rd Deg AV - bronchial asthma/ SE:
- symptomatic HF or QTc >440 (500 if
Block bronchospastic - V Tach
- Toxicity related to ventricular
- bradycardia leading to amiodarone use conditions - QTc prolongation
conduction probs)
syncope w/o pacemaker - 2/3rd deg AV block or SSS - sinus brady <50 bpm - headache
- severe renal
- cardiogenic shock w/o pacemaker - 2/3rd deg AV block BBW:
impairment CrCl <20
- Preexcited a-fib/flutter - bradycardia <50 bpm - long QT syndromes - Life threatening
- use w/ cimetidine,
- hypersensitivity to - use w erythromycin or - cardiogenic shock arrhythmias
CYP3A4 inhibitors dolutegravir, HCTZ,
drug/iodine - decompensated HF - appropriate treatment
- use w drugs/herbs that itraconazole,
- SSS enviornment (prevent
prolong QT ketoconazole,
- Serum K <4 meQ conversion from
- QTc >500msec PR >280 megestrol,
- QTc interval >450 in maintaining sinus
- severe hepatic impairment prochlorperazine,
S.E: a-fib/flutter rhythm)
trimethoprim,
- bradycardia, verapamil, biktarvy
BBW: hypotension (inhibit renal
- life-threatening - AV block Monitoring: secretion)
arrhythmia - Qtc prolongation - ECG/HR/BP/rhythm
- acute hepatotoxicity S.E: - S/s of new or worsening Monitoring:
- hepatotoxicity Monitoring:
- pulmonary toxicity - Hepatotoxicity HF, pulmonary tox, liver BBW: - SCr, CrCl
- pulmonary toxicity - electrolytes (K, Mg)
- photosensitivity, rash, - QTc prolongation injury - Life threatening - Mg and K
- worsening arrhythmias - continuous ECG for at
SJS/TENs (rare) - pulmonary toxicity - serum K and Mg proarrhythmia - HR/BP SE:
Monitoring: least 4 hours
- blue-gray skin - heart failure - serum liver enzymes, Warnings: - ECG (PR/OTc - Headache
- ECG/BP/HR
- thyroid effects - increased SCr bilirubin - bronchospasm interval esp w/ IV) - V-tach (torsades)
- CXR/pulm function tests
- cornal microdeposits - bradycardia - verify pregnancy status - HF (initiation/titration) - Serum glucose (DM) BBW:
- LFTs and thyroid function
- peripheral neurop, - asthenia prior to use - renal impairment - s/s HF - Arrhythmias
- serum K and mg
tremor, dizziness (CNS) SE: Monitoring:
- Bradycardia - ECG (QTc)
- dizziness - SCr
- palpitations - Serum K and Mg
- fatigue
- dyspnea
