Antiarrhythmics: Difference between revisions
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== [[Ibutilide]] == | == [[Ibutilide]] == | ||
== Diltiazem == | == [[Diltiazem]] == | ||
== 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
- 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