Solu-Medrol Reconstitution Volumes
The volume of sterile water or diluent needed to reconstitute Solu-Medrol varies by vial size: 40 mg uses 1 mL, 125 mg uses 2 mL, 500 mg uses 4-8 mL, 1 gram uses 8-16 mL, and 2 grams uses 30.6 mL 1.
Specific Reconstitution Volumes by Vial Size
The FDA-approved labeling provides exact reconstitution instructions for each Solu-Medrol formulation 1:
Preservative-Free Act-O-Vial Formulations:
- 40 mg vial: Add diluent to make 1 mL total volume (40 mg/mL concentration)
- 125 mg vial: Add diluent to make 2 mL total volume (62.5 mg/mL concentration)
- 500 mg vial: Add diluent to make 4 mL total volume (125 mg/mL concentration)
- 1 gram vial: Add diluent to make 8 mL total volume (125 mg/mL concentration)
Formulations Requiring Bacteriostatic Water (with Benzyl Alcohol):
- 500 mg vial: Reconstitute with 8 mL of bacteriostatic water
- 1 gram vial: Reconstitute with 16 mL of bacteriostatic water
- 2 gram vial: Reconstitute with 30.6 mL of bacteriostatic water
Critical Reconstitution Guidelines
Use only the accompanying diluent or Bacteriostatic Water for Injection with Benzyl Alcohol when reconstituting Solu-Medrol 1. The product labeling explicitly states that Solu-Medrol should not be diluted or mixed with other solutions due to possible physical incompatibilities 1.
Important Caveats:
- Benzyl alcohol warning: Formulations preserved with benzyl alcohol should be avoided in neonates and premature infants due to potential toxicity 1
- Stability after reconstitution: Once mixed, the solution should be used within 48 hours 1
- Further dilution: After initial reconstitution, the solution may be further diluted in 5% dextrose in water, isotonic saline, or 5% dextrose in isotonic saline for IV infusion 1
The Act-O-Vial system contains the powder in the lower chamber and diluent in the upper chamber, which are mixed by pressing the plastic activator to force the diluent into the lower chamber 1.