Should I prepare a 365 mg dose of liposomal amphotericin B (amphotericin B liposomal) by mixing seven reconstituted vials into a 500 mL bag of 5% dextrose (5D) and infuse it over six hours?

Liposomal Amphotericin B Preparation: 365 mg Dose

No, you should NOT mix 7 vials into a 500 mL bag—this violates FDA labeling requirements for final concentration and exceeds recommended infusion volumes.

Correct Preparation Method

According to FDA labeling, you must prepare liposomal amphotericin B (AmBisome) as follows 1:

Reconstitution Steps

• Each 50 mg vial requires 12 mL Sterile Water for Injection (NOT saline)
• This yields 4 mg/mL concentration
• For 365 mg: you need 7.3 vials (round to 8 vials = 400 mg, or use 7 vials = 350 mg)
• Shake vigorously for 30 seconds after adding water

Critical Dilution Requirements 1

The FDA label mandates a final concentration of 1-2 mg/mL (lower concentrations of 0.2-0.5 mg/mL are acceptable for infants/small children only)

For 365 mg dose:

• Minimum volume: 182.5 mL of 5% dextrose (for 2 mg/mL concentration)
• Maximum volume: 365 mL of 5% dextrose (for 1 mg/mL concentration)
• Your proposed 500 mL bag would create 0.73 mg/mL—below the FDA-approved range for adults

Proper Preparation

1. Reconstitute 8 vials (or 7 if accepting 350 mg dose)
2. Filter through provided 5-micron filter
3. Add to 250-365 mL of 5% dextrose to achieve 1-2 mg/mL final concentration
4. Use in-line filter ≥1.0 micron during infusion

Infusion Duration

Infuse over 2 hours as standard practice 1. The FDA label states:

• Infusion time may be reduced to approximately 60 minutes if well-tolerated
• Duration may be increased if patient experiences discomfort
• Your proposed 6-hour infusion is unnecessarily prolonged and not supported by labeling

Stability Concerns

Critical timing requirements 1:

• Reconstituted concentrate: stable 24 hours at 2-8°C
• Diluted product: must begin infusion within 6 hours
• Do not freeze
• No preservatives present—strict aseptic technique required

Recent research demonstrates that more dilute formulations (0.2 mg/mL) show greater drug aggregation and cytotoxicity when stored at room temperature 2. This provides additional evidence against your proposed dilute 0.73 mg/mL concentration.

Common Pitfalls to Avoid

1. Never use saline for reconstitution or add to reconstituted product—causes precipitation 1
2. Never exceed 2 mg/mL or go below 1 mg/mL for adult patients (violates FDA labeling)
3. Never skip the 5-micron filtration step during preparation
4. Never use if precipitation or foreign matter present
5. Flush existing IV lines with 5% dextrose before infusion or use separate line 1

Dosing Context

The approved dosing for aspergillosis is 3-5 mg/kg/day 3. For a 73 kg patient, 365 mg = 5 mg/kg, which is appropriate. However, evidence does not support routine escalation beyond 5-6 mg/kg/day, as higher doses increase nephrotoxicity without proven survival benefit 4.