Antiarrhythmics: Difference between revisions

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== [[Ibutilide]] ==
== [[Ibutilide]] ==


== Diltiazem ==
== [[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 ==
== Atropine ==

Revision as of 21:45, 18 November 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

Esmolol

Labetalol

Sotalol

Amiodarone

Ibutilide

Diltiazem

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

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