Antiarrhythmics: Difference between revisions
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==Lidocaine== | ==Lidocaine== | ||
===Adult Dosing=== | === Adult Dosing === | ||
*Loading dose = 1-1.5 mg/kg | *Loading dose = 1-1.5 mg/kg | ||
**Additional boluses of 0.5-0.75 mg/kg q5-10min up to max of 3mg/kg | **Additional boluses of 0.5-0.75 mg/kg q5-10min up to max of 3mg/kg | ||
**If effective start infusion of 2mg/min | **If effective start infusion of 2mg/min | ||
===Contraindications=== | === Contraindications === | ||
*High SA or AV block | *High SA or AV block | ||
===Indications=== | === Indications === | ||
*Treatment of ventricular arrhythmias and ectopy | *Treatment of ventricular arrhythmias and ectopy | ||
**Considered 2nd-line to amiodarone for tx of V-fib and pulseless v-tach | **Considered 2nd-line to amiodarone for tx of V-fib and pulseless v-tach | ||
===Mechanism of Action=== | === Mechanism of Action === | ||
*Class Ib | *Class Ib | ||
**Binds to fast Na channels in inactive state thereby inhibiting recovery after repolarization | **Binds to fast Na channels in inactive state thereby inhibiting recovery after repolarization | ||
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*Little effect on vascular tone, contractility or cardiac output | *Little effect on vascular tone, contractility or cardiac output | ||
===Adverse Drug Rxns=== | === Adverse Drug Rxns === | ||
*CNS | *CNS | ||
**Abrupt change in MS, drowsiness, confusion, sz | **Abrupt change in MS, drowsiness, confusion, sz | ||
===Kinetics=== | === Kinetics === | ||
*Onset of action = 45-90s | *Onset of action = 45-90s | ||
*Duration of action = 10-20min | *Duration of action = 10-20min | ||
==Procainamide== | == Procainamide == | ||
=== Adult Dosing === | |||
*Continuous infusion rate has fewer adverse effects | *Continuous infusion rate has fewer adverse effects | ||
**20-50mg/min for 25-30min | **20-50mg/min for 25-30min | ||
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***If effective start cont infusion of 1-4mg/min | ***If effective start cont infusion of 1-4mg/min | ||
===Contraindications=== | === Contraindications === | ||
*Not recommended for V-fib or pulseless V-tach (too long to dose) | *Not recommended for V-fib or pulseless V-tach (too long to dose) | ||
*2nd or 3rd AV block | *2nd or 3rd AV block | ||
| Line 43: | Line 51: | ||
*Myasthenia gravis | *Myasthenia gravis | ||
===Indications=== | === Indications === | ||
*Wide-complex tachycardia of unknown type (in pts w/ preserved LV function) | *Wide-complex tachycardia of unknown type (in pts w/ preserved LV function) | ||
*Stable V-tach | *Stable V-tach | ||
===Mechanism of Action=== | === Mechanism of Action === | ||
*Class Ia | *Class Ia | ||
**Binds to fast Na channels in inactive state thereby inhibiting recovery after repolarization | **Binds to fast Na channels in inactive state thereby inhibiting recovery after repolarization | ||
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**May act as negative inotrope, cause hypotension (peripheral vasodilation) | **May act as negative inotrope, cause hypotension (peripheral vasodilation) | ||
===Adverse Drug Rxns=== | === Adverse Drug Rxns === | ||
*Myocardial depression | *Myocardial depression | ||
*Watch for QRS/QT prolongation, V-tach, Vfib, complete AV block, torsades | *Watch for QRS/QT prolongation, V-tach, Vfib, complete AV block, torsades | ||
===Kinetics=== | |||
=== Kinetics === | |||
*Onset of action = 5-10min | *Onset of action = 5-10min | ||
==Esmolol== | == Esmolol == | ||
=== Adult Dosing === | |||
*Loading dose = 500mcg/kg bolus over 1min | *Loading dose = 500mcg/kg bolus over 1min | ||
**Follow this w/ infusion at 50mcg/kg/min for 4min | **Follow this w/ infusion at 50mcg/kg/min for 4min | ||
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***If no response give another 500 bolus, incr infusion to 200 | ***If no response give another 500 bolus, incr infusion to 200 | ||
===Contraindications=== | === Contraindications === | ||
*Cardiogenic shock | *Cardiogenic shock | ||
*2nd or 3rd AV block | *2nd or 3rd AV block | ||
===Indications=== | === Indications === | ||
*Supraventricular arrhythmias | *Supraventricular arrhythmias | ||
===Mechanism of Action=== | === Mechanism of Action === | ||
*Class II - Short-acting Beta1 blocker | *Class II - Short-acting Beta1 blocker | ||
===Adverse Drug Rxns=== | === Adverse Drug Rxns === | ||
*Hypotension | *Hypotension | ||
*Bronchospasm | *Bronchospasm | ||
===Kinetics=== | === Kinetics === | ||
Onset of action = 1-4min | |||
Duration of action = <30min | Onset of action = 1-4min Duration of action = <30min | ||
== Labetalol == | |||
=== Adult Dosing === | |||
*Bolus dosing | *Bolus dosing | ||
**20mg IV followed by 40-80mg q10min up to total of 300mg | **20mg IV followed by 40-80mg q10min up to total of 300mg | ||
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**0.5-2mg/min | **0.5-2mg/min | ||
===Indications=== | === Indications === | ||
*HTN in setting of myocardial ischemia | *HTN in setting of myocardial ischemia | ||
*HTN in setting of neurologic injury | *HTN in setting of neurologic injury | ||
*HTN in setting of preeclampsia/eclampsia | *HTN in setting of preeclampsia/eclampsia | ||
===Mechanism of Action=== | === Mechanism of Action === | ||
*Class II - Nonselective beta blocker | *Class II - Nonselective beta blocker | ||
*Alpha1 blocker | *Alpha1 blocker | ||
===Adverse Drug Rxns=== | === Adverse Drug Rxns === | ||
*Orthostatic hypotension | *Orthostatic hypotension | ||
===Kinetics=== | === Kinetics === | ||
*Onset of action = 2-5min (IV) | *Onset of action = 2-5min (IV) | ||
*Duration of action = 2-4hr (IV) | *Duration of action = 2-4hr (IV) | ||
==Sotalol== | == Sotalol == | ||
===Adult Dosing=== | |||
=== Adult Dosing === | |||
*80mg PO BID | *80mg PO BID | ||
===Indications=== | === Indications === | ||
*Suppression of ventricular arrhythmias refractory to other meds | *Suppression of ventricular arrhythmias refractory to other meds | ||
*Suppression of SVT, a-fib | *Suppression of SVT, a-fib | ||
===Mechanism of Action=== | === Mechanism of Action === | ||
*Class II - Nonselective beta-blocker | *Class II - Nonselective beta-blocker | ||
*Class III effects (prolongs repol and refractoriness) | *Class III effects (prolongs repol and refractoriness) | ||
===Adverse Drug Rxns=== | === Adverse Drug Rxns === | ||
*Hypotension, bradycardia | *Hypotension, bradycardia | ||
*Proarrhythmia (esp in pts w/ hypokalemia) | *Proarrhythmia (esp in pts w/ hypokalemia) | ||
===Kinetics=== | |||
=== Kinetics === | |||
*Onset of action = 2-3hr | *Onset of action = 2-3hr | ||
*Duration of action = 24hr | *Duration of action = 24hr | ||
==Amiodarone== | == Amiodarone == | ||
===Adult Dosing=== | |||
=== Adult Dosing === | |||
*V-fib/pulseless V-tach | *V-fib/pulseless V-tach | ||
**Loading dose = 300mg IV bolus followed by 150mg bolus prn | **Loading dose = 300mg IV bolus followed by 150mg bolus prn | ||
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***Follow by infusion of 1mg/min x 6hr; 0.5mg/min thereafter | ***Follow by infusion of 1mg/min x 6hr; 0.5mg/min thereafter | ||
===Contraindications=== | === Contraindications === | ||
*Iodine or shellfish allergy | *Iodine or shellfish allergy | ||
*Pregnancy | *Pregnancy | ||
===Indications=== | === Indications === | ||
*Ventricular and supraventricular arrhythmias | *Ventricular and supraventricular arrhythmias | ||
*1st line for pulseless V-tach/V-fib | *1st line for pulseless V-tach/V-fib | ||
*Used for atrial arrhythmias in pts w/ decr EF | *Used for atrial arrhythmias in pts w/ decr EF | ||
===Mechanism of Action=== | === Mechanism of Action === | ||
*Class III - Inhibits potassium channels | *Class III - Inhibits potassium channels | ||
**Impairs SA and AV node conduction | **Impairs SA and AV node conduction | ||
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*Also has class I & II properties | *Also has class I & II properties | ||
===Adverse Drug Rxns=== | === Adverse Drug Rxns === | ||
*Bradycardia, hypotension | *Bradycardia, hypotension | ||
*Prolonged QT | *Prolonged QT | ||
==Ibutilide== | == Ibutilide == | ||
===Adult Dosing=== | |||
=== Adult Dosing === | |||
*Loading dose = 1mg IV in 50mL D5W over 10min (wt>60kg) | *Loading dose = 1mg IV in 50mL D5W over 10min (wt>60kg) | ||
*Loading dose = 0.01mg/kg IV in 50mL D5W over 10min (wt<60kg) | *Loading dose = 0.01mg/kg IV in 50mL D5W over 10min (wt<60kg) | ||
*Dose may be repeated 10min after completion of 1st dose | *Dose may be repeated 10min after completion of 1st dose | ||
===Indications=== | === Contraindications === | ||
=== Indications === | |||
*Rapid conversion of recent-onset A-fib/flutter to NSR | *Rapid conversion of recent-onset A-fib/flutter to NSR | ||
===Mechanism of Action=== | === Mechanism of Action === | ||
*Class III - Prolongs AP and refractory period | *Class III - Prolongs AP and refractory period | ||
===Adverse Drug Rxns=== | |||
=== Adverse Drug Rxns === | |||
*QT prolongation, V-tach, torsades | *QT prolongation, V-tach, torsades | ||
*Observe for 4hr after infusion | *Observe for 4hr after infusion | ||
===Kinetics=== | === Kinetics === | ||
*Onset of action = 20-30min | *Onset of action = 20-30min | ||
*Duration of action = 24hr | *Duration of action = 24hr | ||
==Diltiazem== | == Diltiazem == | ||
===Adult Dosing=== | |||
=== Adult Dosing === | |||
*Loading dose = 0.25mg/kg (max=20mg) IV bolus over 2min | *Loading dose = 0.25mg/kg (max=20mg) IV bolus over 2min | ||
**If ineffective after 15min: 0.35mg/g (max=25mg) over 2min | **If ineffective after 15min: 0.35mg/g (max=25mg) over 2min | ||
**If effective: Start infusion at 5-15mg/hr | **If effective: Start infusion at 5-15mg/hr | ||
===Contraindications=== | === Contraindications === | ||
*Wide-complex tachycardia due to bypass tract | *Wide-complex tachycardia due to bypass tract | ||
===Indications=== | === Indications === | ||
*Conversion of PSVT to NSR | *Conversion of PSVT to NSR | ||
*Slow RVR in a-fib/flutter | *Slow RVR in a-fib/flutter | ||
===Mechanism of Action=== | === Mechanism of Action === | ||
*Class IV - Inhibits Ca influx | *Class IV - Inhibits Ca influx | ||
**Slows AV nodal conduction | **Slows AV nodal conduction | ||
===Adverse Drug Rxns=== | |||
=== Adverse Drug Rxns === | |||
Bradycardia, CHF, AV block, BBB, hypotension | Bradycardia, CHF, AV block, BBB, hypotension | ||
===Kinetics=== | === Kinetics === | ||
*Onset of action = 2-3min (IV) | *Onset of action = 2-3min (IV) | ||
*Duration of action = 1-3hr (IV) | *Duration of action = 1-3hr (IV) | ||
==Atropine== | == Atropine == | ||
===Adult Dosing=== | |||
=== Adult Dosing === | |||
*Loading dose = 0.5mg rapid IV bolus q3-5min (max = 0.04 milligram/kg) | *Loading dose = 0.5mg rapid IV bolus q3-5min (max = 0.04 milligram/kg) | ||
*May be given IM, IO, SC | *May be given IM, IO, SC | ||
===Indications=== | === Indications === | ||
*Symptomatic sinus or AV nodal bradycardia | *Symptomatic sinus or AV nodal bradycardia | ||
===Mechanism of Action=== | === Mechanism of Action === | ||
*Parasympatholytic | *Parasympatholytic | ||
**Increases sinus/AV conduction | **Increases sinus/AV conduction | ||
===Adverse Drug Rxns=== | === Adverse Drug Rxns === | ||
*Increased O2 consumption | *Increased O2 consumption | ||
*If given slowly (or <0.5mg) may lead to paradoxical bradycardia | *If given slowly (or <0.5mg) may lead to paradoxical bradycardia | ||
===Kinetics=== | |||
=== Kinetics === | |||
*Onset of action = 2-4min | *Onset of action = 2-4min | ||
*Duration of action = 5hr | *Duration of action = 5hr | ||
==Adenosine== | == Adenosine == | ||
===Adult Dosing=== | |||
=== Adult Dosing === | |||
*6mg rapid IV bolus over 1-2s | *6mg rapid IV bolus over 1-2s | ||
**If ineffective can try 12mg 2min later | **If ineffective can try 12mg 2min later | ||
***If still ineffective can try another 12mg | ***If still ineffective can try another 12mg | ||
===Contraindications=== | === Contraindications === | ||
*2nd, 3rd AV block | *2nd, 3rd AV block | ||
*Sick sinus syndrome | *Sick sinus syndrome | ||
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*No effect on anterograde WPW | *No effect on anterograde WPW | ||
===Indications=== | === Indications === | ||
*Conversion of reentrant PSVT to NSR | *Conversion of reentrant PSVT to NSR | ||
===Mechanism of Action=== | === Mechanism of Action === | ||
*Negative inotropic, dromotropic, chronotropic effects | *Negative inotropic, dromotropic, chronotropic effects | ||
*Transient AV nodal block | *Transient AV nodal block | ||
===Adverse Drug Rxns=== | === Adverse Drug Rxns === | ||
*Bronchoconstriction (responds to bronchodilators) | *Bronchoconstriction (responds to bronchodilators) | ||
*Bradyarrhythmia | *Bradyarrhythmia | ||
*Hypotension (if given too slowly) | *Hypotension (if given too slowly) | ||
===Kinetics=== | === Kinetics === | ||
Onset of action = 20-30s | |||
Duration of action = 60-90s | Onset of action = 20-30s Duration of action = 60-90s | ||
== Digoxin == | |||
=== Adult Dosing === | |||
*Loading dose = 0.25 mg IV q2hr until effect (max total = 1.5 mg | *Loading dose = 0.25 mg IV q2hr until effect (max total = 1.5 mg | ||
===Contraindications=== | === Contraindications === | ||
*WPW | *WPW | ||
**Increases conduction velocity in atrial tissue | **Increases conduction velocity in atrial tissue | ||
===Indications=== | === Indications === | ||
*RVR control in a-fib/flutter, PSVT | *RVR control in a-fib/flutter, PSVT | ||
===Mechanism of Action=== | === Mechanism of Action === | ||
*Inhibits NaK pump | *Inhibits NaK pump | ||
**Positive inotropy | **Positive inotropy | ||
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**Indirect vagal stimulator | **Indirect vagal stimulator | ||
===Adverse Drug Rxns=== | === Adverse Drug Rxns === | ||
*GI - N/V, diarrhea, abd pain | *GI - N/V, diarrhea, abd pain | ||
*CV - Bradycardia, SA/AV block, ventr arrhythmias | *CV - Bradycardia, SA/AV block, ventr arrhythmias | ||
===Kinetics=== | === Kinetics === | ||
Onset of action = 1.5-4hr (IV) | Onset of action = 1.5-4hr (IV) | ||
==Isoproterenol== | == Isoproterenol == | ||
===Adult Dosing=== | |||
=== Adult Dosing === | |||
2-10mcg/min IV by continuous infusion | 2-10mcg/min IV by continuous infusion | ||
===Indications=== | === Indications === | ||
*Refractory torsades | *Refractory torsades | ||
*Refractory symptomatic bradycardia | *Refractory symptomatic bradycardia | ||
===Mechanism of Action=== | === Mechanism of Action === | ||
*Beta agonist | *Beta agonist | ||
===Adverse Drug Rxns=== | === Adverse Drug Rxns === | ||
*Dramatic increase in O2 demand | *Dramatic increase in O2 demand | ||
*V-tach (use lowest dose possible) | *V-tach (use lowest dose possible) | ||
===Kinetics=== | === Kinetics === | ||
*Onset of action = 1-5min | *Onset of action = 1-5min | ||
*Duration of action = 1-2hr | *Duration of action = 1-2hr | ||
==Magnesium== | == Magnesium == | ||
===Adult Dosing=== | |||
=== Adult Dosing === | |||
*Loading dose = 1-2gm in 10mL D5W over 1-2min (cardiac arrest) | *Loading dose = 1-2gm in 10mL D5W over 1-2min (cardiac arrest) | ||
*Loading dose = 1-4gm in 50-100 D5W over 20-60min (spontaneous circulation) | *Loading dose = 1-4gm in 50-100 D5W over 20-60min (spontaneous circulation) | ||
===Contraindications=== | === Contraindications === | ||
=== Indications === | |||
*Torsades | *Torsades | ||
*Refractory v-tach/fib (regardless of Mg level) | *Refractory v-tach/fib (regardless of Mg level) | ||
===Mechanism of Action=== | |||
=== Mechanism of Action === | |||
*Increases vasomotor tone | *Increases vasomotor tone | ||
*Prolongs AV conduction; prolongs refractoriness | *Prolongs AV conduction; prolongs refractoriness | ||
===Adverse Drug Rxns=== | |||
=== Adverse Drug Rxns === | |||
*Hypotension (rare) | *Hypotension (rare) | ||
===Kinetics=== | |||
=== Kinetics === | |||
*Onset of action = Immediate | *Onset of action = Immediate | ||
*Duration of action = 30min | *Duration of action = 30min | ||
===Source=== | === Source === | ||
Tintinalli | Tintinalli | ||
[[Category:Drugs]] | <br/>[[Category:Drugs]] <br/>[[Category:Cards]] <br/><br/><br/> | ||
[[Category:Cards]] | |||
Revision as of 21:54, 10 May 2011
Lidocaine
Adult Dosing
- Loading dose = 1-1.5 mg/kg
- Additional boluses of 0.5-0.75 mg/kg q5-10min up to max of 3mg/kg
- If effective start infusion of 2mg/min
Contraindications
- High SA or AV block
Indications
- Treatment of ventricular arrhythmias and ectopy
- Considered 2nd-line to amiodarone for tx of V-fib and pulseless v-tach
Mechanism of Action
- Class Ib
- Binds to fast Na channels in inactive state thereby inhibiting recovery after repolarization
- Acts preferentially on ischemic tissue
- Elevates V-fib threshold
- Suppresses ventricular ectopy
- Little effect on vascular tone, contractility or cardiac output
Adverse Drug Rxns
- CNS
- Abrupt change in MS, drowsiness, confusion, sz
Kinetics
- Onset of action = 45-90s
- Duration of action = 10-20min
Procainamide
Adult Dosing
- Continuous infusion rate has fewer adverse effects
- 20-50mg/min for 25-30min
- Cont until arrhythmia is suppressed, hypotension, QRS >50% or max dose (17mg/kg)
- If effective start cont infusion of 1-4mg/min
- 20-50mg/min for 25-30min
Contraindications
- Not recommended for V-fib or pulseless V-tach (too long to dose)
- 2nd or 3rd AV block
- Severe glycoside intoxication
- Prolonged QT
- Myasthenia gravis
Indications
- Wide-complex tachycardia of unknown type (in pts w/ preserved LV function)
- Stable V-tach
Mechanism of Action
- Class Ia
- Binds to fast Na channels in inactive state thereby inhibiting recovery after repolarization
- Prolongs action potential and reduces speed of impulse conduction
- Depresses myocardial conduction
- May act as negative inotrope, cause hypotension (peripheral vasodilation)
Adverse Drug Rxns
- Myocardial depression
- Watch for QRS/QT prolongation, V-tach, Vfib, complete AV block, torsades
Kinetics
- Onset of action = 5-10min
Esmolol
Adult Dosing
- Loading dose = 500mcg/kg bolus over 1min
- Follow this w/ infusion at 50mcg/kg/min for 4min
- If no response give another 500 bolus, incr infusion to 100
- If no response give another 500 bolus, incr infusion to 200
- Follow this w/ infusion at 50mcg/kg/min for 4min
Contraindications
- Cardiogenic shock
- 2nd or 3rd AV block
Indications
- Supraventricular arrhythmias
Mechanism of Action
- Class II - Short-acting Beta1 blocker
Adverse Drug Rxns
- Hypotension
- Bronchospasm
Kinetics
Onset of action = 1-4min Duration of action = <30min
Labetalol
Adult Dosing
- Bolus dosing
- 20mg IV followed by 40-80mg q10min up to total of 300mg
- Infusion dosing
- 0.5-2mg/min
Indications
- HTN in setting of myocardial ischemia
- HTN in setting of neurologic injury
- HTN in setting of preeclampsia/eclampsia
Mechanism of Action
- Class II - Nonselective beta blocker
- Alpha1 blocker
Adverse Drug Rxns
- Orthostatic hypotension
Kinetics
- Onset of action = 2-5min (IV)
- Duration of action = 2-4hr (IV)
Sotalol
Adult Dosing
- 80mg PO BID
Indications
- Suppression of ventricular arrhythmias refractory to other meds
- Suppression of SVT, a-fib
Mechanism of Action
- Class II - Nonselective beta-blocker
- Class III effects (prolongs repol and refractoriness)
Adverse Drug Rxns
- Hypotension, bradycardia
- Proarrhythmia (esp in pts w/ hypokalemia)
Kinetics
- Onset of action = 2-3hr
- Duration of action = 24hr
Amiodarone
Adult Dosing
- V-fib/pulseless V-tach
- Loading dose = 300mg IV bolus followed by 150mg bolus prn
- Stable V-tach or SVT
- Loading dose = 150mg IV in 100mL D5W over 10min
- Follow by infusion of 1mg/min x 6hr; 0.5mg/min thereafter
- Loading dose = 150mg IV in 100mL D5W over 10min
Contraindications
- Iodine or shellfish allergy
- Pregnancy
Indications
- Ventricular and supraventricular arrhythmias
- 1st line for pulseless V-tach/V-fib
- Used for atrial arrhythmias in pts w/ decr EF
Mechanism of Action
- Class III - Inhibits potassium channels
- Impairs SA and AV node conduction
- Decreases automaticity
- Prolongs refractory period in accessory pathways
- Also has class I & II properties
Adverse Drug Rxns
- Bradycardia, hypotension
- Prolonged QT
Ibutilide
Adult Dosing
- Loading dose = 1mg IV in 50mL D5W over 10min (wt>60kg)
- Loading dose = 0.01mg/kg IV in 50mL D5W over 10min (wt<60kg)
- Dose may be repeated 10min after completion of 1st dose
Contraindications
Indications
- Rapid conversion of recent-onset A-fib/flutter to NSR
Mechanism of Action
- Class III - Prolongs AP and refractory period
Adverse Drug Rxns
- QT prolongation, V-tach, torsades
- Observe for 4hr after infusion
Kinetics
- Onset of action = 20-30min
- Duration of action = 24hr
Diltiazem
Adult Dosing
- Loading dose = 0.25mg/kg (max=20mg) IV bolus over 2min
- If ineffective after 15min: 0.35mg/g (max=25mg) over 2min
- If effective: Start infusion at 5-15mg/hr
Contraindications
- Wide-complex tachycardia due to bypass tract
Indications
- Conversion of PSVT to NSR
- Slow RVR in a-fib/flutter
Mechanism of Action
- Class IV - Inhibits Ca influx
- Slows AV nodal conduction
Adverse Drug Rxns
Bradycardia, CHF, AV block, BBB, hypotension
Kinetics
- Onset of action = 2-3min (IV)
- Duration of action = 1-3hr (IV)
Atropine
Adult Dosing
- Loading dose = 0.5mg rapid IV bolus q3-5min (max = 0.04 milligram/kg)
- May be given IM, IO, SC
Indications
- Symptomatic sinus or AV nodal bradycardia
Mechanism of Action
- Parasympatholytic
- Increases sinus/AV conduction
Adverse Drug Rxns
- Increased O2 consumption
- If given slowly (or <0.5mg) may lead to paradoxical bradycardia
Kinetics
- Onset of action = 2-4min
- Duration of action = 5hr
Adenosine
Adult Dosing
- 6mg rapid IV bolus over 1-2s
- If ineffective can try 12mg 2min later
- If still ineffective can try another 12mg
- If ineffective can try 12mg 2min later
Contraindications
- 2nd, 3rd AV block
- Sick sinus syndrome
- Reentrant SVTs not involving AV node are not terminated
- No effect on anterograde WPW
Indications
- Conversion of reentrant PSVT to NSR
Mechanism of Action
- Negative inotropic, dromotropic, chronotropic effects
- Transient AV nodal block
Adverse Drug Rxns
- Bronchoconstriction (responds to bronchodilators)
- Bradyarrhythmia
- Hypotension (if given too slowly)
Kinetics
Onset of action = 20-30s Duration of action = 60-90s
Digoxin
Adult Dosing
- Loading dose = 0.25 mg IV q2hr until effect (max total = 1.5 mg
Contraindications
- WPW
- Increases conduction velocity in atrial tissue
Indications
- RVR control in a-fib/flutter, PSVT
Mechanism of Action
- Inhibits NaK pump
- Positive inotropy
- Negative chronotropy/dromotropy
- Indirect vagal stimulator
Adverse Drug Rxns
- GI - N/V, diarrhea, abd pain
- CV - Bradycardia, SA/AV block, ventr arrhythmias
Kinetics
Onset of action = 1.5-4hr (IV)
Isoproterenol
Adult Dosing
2-10mcg/min IV by continuous infusion
Indications
- Refractory torsades
- Refractory symptomatic bradycardia
Mechanism of Action
- Beta agonist
Adverse Drug Rxns
- Dramatic increase in O2 demand
- V-tach (use lowest dose possible)
Kinetics
- Onset of action = 1-5min
- Duration of action = 1-2hr
Magnesium
Adult Dosing
- Loading dose = 1-2gm in 10mL D5W over 1-2min (cardiac arrest)
- Loading dose = 1-4gm in 50-100 D5W over 20-60min (spontaneous circulation)
Contraindications
Indications
- Torsades
- Refractory v-tach/fib (regardless of Mg level)
Mechanism of Action
- Increases vasomotor tone
- Prolongs AV conduction; prolongs refractoriness
Adverse Drug Rxns
- Hypotension (rare)
Kinetics
- Onset of action = Immediate
- Duration of action = 30min
Source
Tintinalli