Generic name: amiodarone hydrochloride
Dosage form: injection
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Amiodarone shows considerable interindividual variation in response. Thus, although a starting dose adequate to suppress life-threatening arrhythmias is needed, close monitoring with adjustment of dose as needed is essential. The recommended starting dose of Cordarone I.V. is about 1000 mg over the first 24 hours of therapy, delivered by the following infusion regimen:
|Loading infusions||FirstRapid:||150 mg over the FIRST 10 minutes (15 mg/min).|
|Add 3 mL of Cordarone I.V. (150 mg) to 100 mL D5W (concentration = 1.5 mg/mL).
Infuse 100 mL over 10 minutes.
|Followed by Slow:||360 mg over the NEXT 6 hours (1 mg/min).|
|Add 18 mL of Cordarone I.V. (900 mg) to 500 mL D5W (concentration = 1.8 mg/mL).|
|Maintenance infusion||540 mg over the REMAINING 18 hours (0.5 mg/min).|
|Decrease the rate of the slow loading infusion to 0.5 mg/min.|
After the first 24 hours, the maintenance infusion rate of 0.5 mg/min (720 mg/24 hours) should be continued utilizing a concentration of 1 to 6 mg/mL (Cordarone I.V. concentrations greater than 2 mg/mL should be administered via a central venous catheter). In the event of breakthrough episodes of VF or hemodynamically unstable VT, 150-mg supplemental infusions of Cordarone I.V. mixed in 100 mL of D5W may be administered. Such infusions should be administered over 10 minutes to minimize the potential for hypotension. The rate of the maintenance infusion may be increased to achieve effective arrhythmia suppression.
The first 24-hour dose may be individualized for each patient; however, in controlled clinical trials, mean daily doses above 2100 mg were associated with an increased risk of hypotension. The initial infusion rate should not exceed 30 mg/min.
Based on the experience from clinical studies of Cordarone I.V., a maintenance infusion of up to 0.5 mg/min can be cautiously continued for 2 to 3 weeks regardless of the patient's age, renal function, or left ventricular function. There has been limited experience in patients receiving Cordarone I.V. for longer than 3 weeks.
The surface properties of solutions containing injectable amiodarone are altered such that the drop size may be reduced. This reduction may lead to underdosage of the patient by up to 30% if drop counter infusion sets are used. Cordarone I.V. must be delivered by a volumetric infusion pump.
Cordarone I.V. should, whenever possible, be administered through a central venous catheter dedicated to that purpose. An in-line filter should be used during administration.
Cordarone I.V. loading infusions at much higher concentrations and rates of infusion much faster than recommended have resulted in hepatocellular necrosis and acute renal failure, leading to death (see PRECAUTIONS, Liver Enzyme Elevations).
Cordarone I.V. concentrations greater than 3 mg/mL in D5W have been associated with a high incidence of peripheral vein phlebitis; however, concentrations of 2.5 mg/mL or less appear to be less irritating. Therefore, for infusions longer than 1 hour, Cordarone I.V. concentrations should not exceed 2 mg/mL unless a central venous catheter is used (see ADVERSE REACTIONS, Postmarketing Reports).
Cordarone I.V. infusions exceeding 2 hours must be administered in glass or polyolefin bottles containing D5W. Use of evacuated glass containers for admixing Cordarone I.V. is not recommended as incompatibility with a buffer in the container may cause precipitation.
It is well known that amiodarone adsorbs to polyvinyl chloride (PVC) tubing and the clinical trial dose administration schedule was designed to account for this adsorption. All of the clinical trials were conducted using PVC tubing and its use is therefore recommended. The concentrations and rates of infusion provided in DOSAGE AND ADMINISTRATION reflect doses identified in these studies. Cordarone I.V. has been found to leach out plasticizers, including DEHP [di-(2-ethylhexyl)phthalate] from intravenous tubing (including PVC tubing). The degree of leaching increases when infusing Cordarone I.V. at higher concentrations and lower flow rates than provided in DOSAGE AND ADMINISTRATION. In addition, polysorbate 80, a component of Cordarone I.V., is also known to leach DEHP from PVC (see DESCRIPTION). Therefore, it is important that the recommendations in DOSAGE AND ADMINISTRATION be followed closely.
Cordarone I.V. does not need to be protected from light during administration.
|5% Dextrose in Water (D5W)||1.0 – 6.0||PVC||Physically compatible,
<10% at 2 hours at room temperature.
|5% Dextrose in Water (D5W)||1.0 – 6.0||Polyolefin,
with no amiodarone
loss at 24 hours at room temperature.
Cordarone I.V. in D5W is incompatible with the drugs shown below.
|Cefamandole Nafate||D5W||4 mg/mL||Precipitate|
|Cefazolin Sodium||D5W||4 mg/mL||Precipitate|
|Mezlocillin Sodium||D5W||4 mg/mL||Precipitate|
|Sodium Bicarbonate||D5W||3 mg/mL||Precipitate|
Intravenous to Oral Transition
Patients whose arrhythmias have been suppressed by Cordarone I.V. may be switched to oral Cordarone. The optimal dose for changing from intravenous to oral administration of Cordarone will depend on the dose of Cordarone I.V. already administered, as well as the bioavailability of oral Cordarone. When changing to oral Cordarone therapy, clinical monitoring is recommended, particularly for elderly patients.
Since there are some differences between the safety and efficacy profiles of the intravenous and oral formulations, the prescriber is advised to review the package insert for oral amiodarone when switching from intravenous to oral amiodarone therapy.
Since grapefruit juice is known to inhibit CYP3A4-mediated metabolism of oral amiodarone in the intestinal mucosa, resulting in increased plasma levels of amiodarone, grapefruit juice should not be taken during treatment with oral amiodarone (see PRECAUTIONS, Drug Interactions).
The following table provides suggested doses of oral Cordarone to be initiated after varying durations of Cordarone I.V. administration. These recommendations are made on the basis of a comparable total body amount of amiodarone delivered by the intravenous and oral routes, based on 50% bioavailability of oral amiodarone.
Cordarone I.V. Infusion#
|Initial Daily Dose of
# Assuming a 720 mg/day infusion (0.5 mg/min).
* Cordarone I.V. is not intended for maintenance treatment.
|<1 week||800-1600 mg|
|1-3 weeks||600-800 mg|
|>3 weeks*||400 mg|