Vasopressin Infusion Preparation
Vasopressin should be diluted in either normal saline (0.9% sodium chloride) or 5% dextrose in water (D5W) prior to intravenous administration. 1
Fluid Options for Dilution
The FDA-approved vasopressin drug label explicitly states that vasopressin injection (20 units/mL) must be diluted in one of two fluids 1:
- Normal saline (0.9% sodium chloride)
- 5% dextrose in water (D5W)
Both options are equally acceptable for preparing vasopressin infusions, and the choice between them does not affect clinical efficacy.
Practical Preparation Details
Standard Dilution Protocol
- Vasopressin comes as a 20 units/mL concentrated solution that requires dilution before IV use 1
- The diluted solution should be discarded after:
- 18 hours at room temperature, OR
- 24 hours under refrigeration 1
Extended Stability Considerations
Recent research demonstrates that vasopressin diluted to 0.4 units/mL in 0.9% sodium chloride remains stable for up to 90 days at both room temperature and under refrigeration 2. However, this extended stability is not yet reflected in FDA labeling, so institutional policies may vary.
Clinical Context from Guidelines
While the evidence provided focuses primarily on epinephrine and dopamine infusions in anaphylaxis and shock states, the pattern is consistent: vasopressors are typically diluted in either D5W or normal saline 3. For example, dopamine infusions are prepared as "400 mg in 500 mL D5W" 3, demonstrating the standard practice of using these two diluents for vasoactive medications.
The FDA drug label takes precedence here, clearly establishing that both normal saline and D5W are appropriate and approved diluents for vasopressin infusion preparation.