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Functional Class
Class III Antidysrhythmic (potassium channel blocker)
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Mechanism of Action
- -Acts directly on all cardiac tissues
- -Prolongs duration of the action potential and refractory period by blocking potassium channels
- -Also blocks sodium channels
- -IV form relaxes vascular smooth muscle, decreases peripheral vascular resistance and increases coronary blood flow
- -Blocks the effects of sympathetic stimulation
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Indications
- -Life-threatening ventricular and supraventricular dysrhythmias
- (VF, VT, A-Fib, A-Flutter, SVT, WPW)
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Contraindications
- -Hypersensitivity
- -Cardiogenic shock
- -Severe sinus bradycardia
- -AV block
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Precautions
- -Severe liver disease
- -Pregnancy
- -Nursing mothers
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Side Effects
- CHF
- Angioedema
- Hypotension
- AV block
- Hepatatoxicity
- Cardiogenic shock
- Fatigue
- Bradycardia
- Sinus arrest
- Permanent blindness
- N/V
- Prolonged QT interval
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Interactions
- Increases digoxin levels
- Enhances effects of procainamide, lidocaine, quinidine, and oral anticoagulants
- Calcium channel blockers, beta blockers, fentanyl, and cimetidine may potentiate sinus bradycardia
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Dose/Route
- ADULT
- Pulse:
- 150 mg (in 50-100mL NS) IV over 10 mins. May repeat after 10 mins
Pulseless: 300 mg IVP, repeat in 3-5 mins at 150 mg IVP
Infusion: 1 mg/min over the next 6 hours
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