How to reconstitute and prepare amphotericin B (antifungal medication) liposomal?

Reconstitution and Preparation of Liposomal Amphotericin B (AmBisome)

Liposomal amphotericin B should be reconstituted with sterile water for injection, followed by dilution in 5% dextrose solution for intravenous administration over 1-2 hours. 1

Reconstitution Process

Step 1: Initial Reconstitution

• Use sterile water for injection (not saline or bacteriostatic water)
• Add 12 mL of sterile water to each 50 mg vial of liposomal amphotericin B
• Shake the vial vigorously for at least 30 seconds until all material is completely dispersed
• The reconstituted product will appear as a yellow, translucent suspension
• Final concentration: approximately 4 mg/mL

Step 2: Dilution for Administration

• Further dilute the reconstituted solution with 5% dextrose solution
• Filter through the provided 5-micron filter into the appropriate amount of 5% dextrose
• Final concentration for infusion should be between 0.2-0.5 mg/mL

Step 3: Administration

• Infuse over 1-2 hours
• For initial doses, consider extending infusion time to 2 hours to reduce risk of infusion-related reactions
• Do not use an in-line filter with a pore size less than 1 micron

Important Considerations

Stability Information

• Reconstituted product: stable for 24 hours when stored at 2-8°C (36-46°F)
• Diluted solution: stable for 6 hours at room temperature
• Protect from light during storage
• Do not freeze

Incompatibilities

• Do not mix with saline solutions
• Do not mix with other drugs or electrolytes
• Do not use bacteriostatic water containing preservatives

Dosing Guidelines

• For invasive candidiasis: 3-5 mg/kg once daily 1
• For cryptococcal meningitis in HIV patients: 3-4 mg/kg once daily 1
• For empiric therapy in febrile neutropenia: 3 mg/kg once daily 2

Monitoring and Adverse Effects Management

Pre-medication

• Consider diphenhydramine before infusion to reduce infusion-related reactions 1
• Infusion-related reactions occur in approximately 20% of patients receiving lipid formulations 1
• Most reactions (85%) occur within first 5 minutes of infusion 1

Monitoring During Administration

• Monitor vital signs before, during, and after infusion until stable
• Watch for infusion-related reactions: chest pain, dyspnea, hypoxia, abdominal/flank pain, flushing, urticaria 1
• If reactions occur, temporarily interrupt infusion and administer diphenhydramine 1

Laboratory Monitoring

• Baseline and frequent (1-2 times weekly) serum chemistry values and CBC
• Monitor renal function closely, as nephrotoxicity can occur (though less frequently than with conventional amphotericin B) 3
• Monitor electrolytes, particularly potassium and magnesium levels 1

Clinical Advantages of Liposomal Formulation

Liposomal amphotericin B has several advantages over conventional amphotericin B deoxycholate:

• Significantly less nephrotoxicity (19% vs 34%) 2
• Fewer infusion-related reactions 2
• Higher therapeutic index allowing for higher dosing 4
• Better CNS penetration in cryptococcal meningitis 1

Common Pitfalls to Avoid

• Using saline for reconstitution (causes precipitation)
• Inadequate shaking during reconstitution (results in incomplete dispersion)
• Mixing with other medications or electrolytes
• Using bacteriostatic water containing preservatives
• Filtering through membrane filters less than 1 micron
• Administering too rapidly (increases risk of infusion reactions)

Remember that proper reconstitution and administration techniques are critical for both efficacy and minimizing adverse effects of this potent antifungal medication.