Generic Name: amiodarone hydrochloride
Classification: Antiarrhythmic, Adrenergic blocker (not used as sympatholytic drug)
Pregnancy Category D
- Careful patient assessment and evaluation with continual monitoring of cardiac response are necessary for titrating the dosage. Therapy should begin in the hospital with continual monitoring and emergency equipment on standby. The following is a guide to usual dosage.
- Loading dose: 800–1,600 mg/day PO in divided doses, for 1–3 wk; reduce dose to 600–800 mg/day in divided doses for 1 mo; if rhythm is stable, reduce dose to 400 mg/day in one to two divided doses for maintenance dose. Adjust to the lowest possible dose to limit side effects.
- 1,000 mg IV over 24 hr—150 mg loading dose over 10 min, followed by 360 mg over 6 hr at rate of 1 mg/min. For maintenance infusion, 540 mg at 0.5 mg/min over 18 hr. May be continued up to 96 hr or until rhythm is stable. Switch to oral form as soon as possible.
- Safety and efficacy not established.
- Type III antiarrhythmic: Acts directly on cardiac cell membrane; prolongs repolarization and refractory period; increases ventricular fibrillation threshold; acts on peripheral smooth muscle to decrease peripheral resistance
- Only for treatment of the following documented life-threatening recurrent ventricular arrhythmias that do not respond to other antiarrhythmics or when alternative agents are not tolerated: Recurrent ventricular fibrillation, recurrent hemodynamically unstable ventricular tachycardia. Serious and even fatal toxicity has been reported with this drug; use alternative agents first; very closely monitor patient receiving this drug
- Unlabeled uses: Treatment of refractory sustained or paroxysmal atrial fibrillation and paroxysmal supraventricular tachycardia; treatment of symptomatic atrial flutter
- CNS: Malaise, fatigue, dizziness, tremors, ataxia, paresthesias, lack of coordination
- CV: Cardiac arrhythmias, CHF, cardiac arrest, hypotension
- EENT: Corneal microdeposits (photophobia, dry eyes, halos, blurred vision); ophthalmic abnormalities including permanent blindness
- Endocrine: Hypothyroidism or hyperthyroidism
- GI: Nausea, vomiting, anorexia, constipation, abnormal LFTs, hepatotoxicity
- Respiratory: Pulmonary toxicity—pneumonitis, infiltrates (shortness of breath, cough, rales, wheezes)
- Other: Photosensitivity, angioedema
- Contraindicated with hypersensitivity to amiodarone, sinus node dysfunction, heart block, severe bradycardia, hypokalemia, lactation.
- Use cautiously with thyroid dysfunction, pregnancy.
CLINICAL ALERT! Name confusion has occurred with amrinone (name has now been changed to inamrinone, but confusion may still occur); use caution.
- History: Hypersensitivity to amiodarone, sinus node dysfunction, heart block, severe bradycardia, hypokalemia, lactation, thyroid dysfunction, pregnancy
- Physical: Skin color, lesions; reflexes, gait, eye examination; P, BP, auscultation, continuous ECG monitoring; R, adventitious sounds, baseline chest X-ray; liver evaluation; LFTs, serum electrolytes, T4, and T3
- WARNING: Reserve use for life-threatening arrhythmias; serious toxicity, including arrhythmias, pulmonary toxicity can occur.
- Monitor cardiac rhythm continuously.
- Monitor for an extended period when dosage adjustments are made.
- WARNING: Monitor for safe and effective serum levels (0.5–2.5 mcg/mL).
- WARNING: Doses of digoxin, quinidine, procainamide, phenytoin, and warfarin may need to be reduced one-third to one-half when amiodarone is started.
- Give drug with meals to decrease GI problems.
- Arrange for ophthalmologic examinations; reevaluate at any sign of optic neuropathy.
- Arrange for periodic chest X-ray to evaluate pulmonary status (every 3–6 mo).
- Arrange for regular periodic blood tests for liver enzymes, thyroid hormone levels.
- Drug dosage will be changed in relation to response of arrhythmias; you will need to be hospitalized during initiation of drug therapy; you will be closely monitored when dosage is changed.
- Have regular medical follow-up, monitoring of cardiac rhythm, chest X-ray, eye examination, blood tests.
- You may experience these side effects: Changes in vision (halos, dry eyes, sensitivity to light; wear sunglasses, monitor light exposure); nausea, vomiting, loss of appetite (take with meals; eat frequent small meals); sensitivity to the sun (use a sunscreen or protective clothing when outdoors); constipation (a laxative may be ordered); tremors, twitching, dizziness, loss of coordination (do not drive, operate dangerous machinery, or undertake tasks that require coordination until drug effects stabilize and your body adjusts to it).
- Report unusual bleeding or bruising; fever, chills; intolerance to heat or cold; shortness of breath, difficulty breathing, cough; swelling of ankles or fingers; palpitations; difficulty with vision.