What is the correct method for administering liposomal amphotericin B intravenously?

How to Administer Liposomal Amphotericin B

Administer liposomal amphotericin B intravenously at 3-5 mg/kg/day as a slow infusion over 2 hours, diluted in 5% dextrose to a concentration of 0.1-2 mg/mL, using strict aseptic technique without any bacteriostatic agents or saline solutions.

Preparation Protocol

Reconstitution Steps

• Reconstitute the lyophilized powder using only sterile water for injection (without bacteriostatic agents)
• Use a sterile needle with minimum 20-gauge diameter
• Shake immediately until the solution is clear
• Further dilute in 5% dextrose injection only - never use saline solutions, as this causes precipitation 1
• Ensure the dextrose solution pH is above 4.2 before use 1

Final Concentration

• Target concentration: 0.1-2 mg/mL in 5% dextrose
• The manufacturer recommends 0.1 mg/mL (1 mg/10 mL) for conventional amphotericin B 1
• Liposomal formulations may tolerate slightly higher concentrations

Critical Preparation Warnings

• Never add bacteriostatic agents (e.g., benzyl alcohol) - these cause precipitation 1
• Never use saline solutions - only 5% dextrose 1
• Use strict aseptic technique throughout - no preservatives are present 1
• Do not use if any precipitation or foreign matter is visible 1

Administration Guidelines

Infusion Parameters

• Infusion duration: 2 hours minimum (up to 6 hours for larger doses) 1
• Administer through peripheral or central IV line
• An in-line membrane filter may be used if pore diameter is ≥1.0 micron 1

Dosing by Indication

For CNS infections (meningitis):

• 5 mg/kg/day IV 2
• Strong recommendation from IDSA 2016 guidelines 2

For candidemia and invasive candidiasis:

• 3-5 mg/kg/day IV 2
• Use with caution in neonates, particularly with urinary tract involvement 2

For ocular infections (endophthalmitis with fluconazole resistance):

• 3-5 mg/kg/day IV 2

For neonatal disseminated candidiasis:

• 3-5 mg/kg/day IV (weak recommendation; use with caution) 2

Test Dose Consideration

While the FDA label for conventional amphotericin B deoxycholate recommends a 1 mg test dose 1, this is not standard practice for liposomal formulations due to their improved tolerability profile. The liposomal formulation has significantly fewer infusion-related reactions than conventional amphotericin B 3, 4.

Storage and Stability

• Store reconstituted admixtures at 4-8°C (refrigerated) 5
• Protection from light is unnecessary 5
• Expiration depends on concentration: 35 days for 0.25 mg/mL; 36 hours for 1.4 mg/mL 5

Common Pitfalls to Avoid

1. Using saline for dilution - This is the most common error and causes immediate precipitation 1

2. Adding bacteriostatic agents - These cause drug precipitation 1

3. Infusing too rapidly - Maintain minimum 2-hour infusion to reduce infusion-related reactions 1

4. Exceeding recommended doses - Doses >6 mg/kg/day increase nephrotoxicity without proven efficacy benefit 6. The AmBiLoad trial showed no benefit from 10 mg/kg/day versus 3 mg/kg/day 3

5. Using filters with pores <1.0 micron - These will trap the liposomal particles 1

Monitoring During Infusion

• Monitor vital signs (temperature, pulse, respiration, blood pressure) every 30 minutes for the first 2-4 hours 1
• Watch for infusion-related reactions (fever, rigors, hypotension)
• Have premedication available (acetaminophen, diphenhydramine, hydrocortisone) for patients with prior reactions

Key Advantages Over Conventional Amphotericin B

Liposomal amphotericin B demonstrates significantly less nephrotoxicity and fewer infusion-related reactions compared to conventional amphotericin B deoxycholate while maintaining equivalent efficacy 3, 4, 7. This improved safety profile justifies its use as first-line therapy despite higher cost.