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Cardiac Glycoside
Digoxin (Lanoxin)
- + inotropic=increase force of contraction.
- -chronotropic=slows heart rate
- -dromotropic=slow conduction
- Bradycardia, Tachycardia, convulsion, halo vision, colored vision (green or yellow)
- Monitor for dig toxicity (Serum Dig level 0.5-2.0. toxic>2.5)
- Increased risk for toxicity if low K+, high Ca+, hyperthyroid, renal dysfunction, or elderly. **Apical pulse for 1 minute. Not with dairy or antacids. St. Johns Wort and psyllium decrease dig effectiveness, and ginseng, hawthorne and licorice increase dig toxicity.
- Antidite: digoxin immune fab.
- CHF, Afib, Aflutter, Supraventricular Tachycardia, Atriual Tachycardia, Cardiogenic shock.
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Phosphodiesterase Inhibitor
Inamrinone (Inocor)-approved for use only on pt not responding to Dig, diuretics and vasodilators.
- Inhibit phosphodiesterase to produce + inotropic, thus vasodilates (increases CA+ thus stronger force of contraction, but can also increase O2 consumption and cause arrhythmias!!!
- Hypokalemia, hepatotoxicity with long term use, Thrombocytopenia.
- IV---dilute only in NS!! Monitor LFT, RFT, electrolytes and PLT count. Precipitates in IV line if given with Lasix. Must use separate IV line.
- Short term use in CHF if unresponsive to Dig, diuretics, and vasodilators.
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Class 1B Antiarrhythmic
Lidocaine (Xylocaine)
- Stabalize cell membrane by binding to Na+ channels (Na+ channel blockers) Local Anesthetics.
- Hypotension, Bradycardia, Confusion, Convulsions.
- Given IV route. Must state "for Cardiac use" as other forms contain epinephrine. Monitor neurologic status and provide for safety.
- For life threatening ventricular arrhythmias. Local anesthetic.
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Class II Antiarrythmics
Propranolol (Inderal)
- Beta Blockers---block SNS, thus decreasing rate, contractility and conduction. Hypotension, Bradycardia, may precipitate CHF, syncope.
- Oral or IV use. Monitor for CHF. May not see increased pulse with exercise. Withhold if pulse <60. D/c gradually to prevent angina. Oral before meals.
- Sysrhythmias d/t excessive SNS activity.
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Class III Antiarrythmics
amiodarone (Cordarone)
- Potassium Channel Blockers. Prolong refractory period by prolonging action potential, delaying repolarization.
- Photosensitivity, corneal microdeposits, pulmonary toxicity, hepatitis and thyroid dysfunction.
- Give IV or orally. Monitor LFT and thyroid**These drugs can be used interchangably!! Toxic if taken with Dig or quinidine. Increased risk of arrhythmias with TCA or antihistamine.
- Treatment of life threatening ventricular arrythmias unresponsive to Class 1B and 1C. **Each med in this class of antiarrhythmics works differently.
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Class IV Antiarrhythmics
diltiazem (Cardizem)
- Ca+ Channel Blockers, this-dromotropic effect (decrease conduction).
- Hypotension, bradycardia, heart block, edema, constipation.
- Given IV or orally. Monitor for CHF and hypotension. MUST AVOID GRAPEFRUIT JUICE.
- PSTV (paroxysmal supraventricular tachycardia). Controls ventricular repsonse to Afib or Aflutter.
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