Why is amiodarone mixed with dextrose?

Why Amiodarone is Mixed in Dextrose

Amiodarone is mixed in dextrose (D5W) rather than normal saline because it forms precipitates with saline solutions, which could lead to medication delivery issues and potential patient harm.

Compatibility and Stability Considerations

Amiodarone has specific compatibility requirements that necessitate its dilution in dextrose solution:

• According to the FDA drug label, amiodarone must be diluted in D5W (5% dextrose in water) for infusions longer than 1 hour 1
• Amiodarone forms precipitates when mixed with normal saline or other incompatible solutions 1
• For infusions exceeding 2 hours, amiodarone must be administered in glass or polyolefin bottles containing D5W 1

Administration Guidelines

When administering intravenous amiodarone, several important considerations apply:

• Concentration should not exceed 2 mg/mL for infusions longer than 1 hour unless using a central venous catheter 1
• Higher concentrations (>3 mg/mL) have been associated with a high incidence of peripheral vein phlebitis 1
• Amiodarone should ideally be administered through a central venous catheter dedicated to that purpose 1
• An in-line filter should be used during administration 1

Potential Complications of Improper Dilution

Failure to properly dilute amiodarone can lead to serious complications:

• Intravenous amiodarone loading infusions at higher concentrations and rates than recommended have resulted in hepatocellular necrosis and acute renal failure, leading to death 1
• Rapid administration of undiluted amiodarone can cause severe hypotension 2
• The cosolvents in standard amiodarone IV formulations (polysorbate 80 and benzyl alcohol) are associated with hypotensive effects that persist throughout the maintenance infusion period 2

Special Considerations

• Amiodarone adsorbs to polyvinyl chloride (PVC) tubing, which can affect drug delivery 1
• Polysorbate 80, a component of amiodarone hydrochloride injection, leaches DEHP [di-(2-ethylhexyl)phthalate] from PVC tubing 1
• The surface properties of solutions containing injectable amiodarone are altered such that drop size may be reduced, potentially leading to underdosage by up to 30% if drop counter infusion sets are used 1
• For this reason, amiodarone must be delivered by a volumetric infusion pump 1

Incompatibilities

Amiodarone in D5W forms precipitates with numerous medications, requiring separate intravenous administration lines when coadministration is necessary 1.

Clinical Implications

Understanding the proper dilution of amiodarone is critical for patient safety:

• Hypotension is a common side effect of IV amiodarone, occurring in approximately 16% of patients 3
• If hypotension or bradycardia occurs during administration, the infusion should be discontinued or the rate reduced 3
• Newer cosolvent-free formulations of amiodarone (e.g., PM101) may cause fewer hypotensive effects but are not yet widely available 4, 2

By properly diluting amiodarone in dextrose solution and following recommended administration guidelines, clinicians can minimize the risk of adverse effects while maintaining the drug's efficacy in treating life-threatening arrhythmias.