Inotrope Solvent Selection
Inotropes should be dissolved in 5% dextrose (glucose) solution rather than 0.9% sodium chloride (normal saline), as this provides superior drug stability over 24 hours and reduces concentration degradation at the point of delivery. 1
Primary Solvent Recommendation
- 5% dextrose (glucose) is the preferred diluent for inotropic agents, particularly dopamine and dobutamine, based on stability data showing significantly less concentration reduction after 24 hours compared to normal saline 1
- Dopamine prepared in 0.9% sodium chloride demonstrates significant concentration reduction at the end of extension sets after 24 hours (p < 0.001), while 5% glucose preparations maintain more stable concentrations 1
- Dobutamine similarly shows greater stability in 5% glucose compared to 0.9% sodium chloride (p < 0.001) 1
FDA-Approved Formulations
- Dopamine hydrochloride is commercially available prediluted in 5% dextrose injection at concentrations of 0.8 mg/mL, 1.6 mg/mL, or 3.2 mg/mL 2
- Milrinone lactate is supplied with 47 mg dextrose (anhydrous) per mL in water for injection, requiring further dilution prior to intravenous administration 3
- These FDA-approved formulations confirm that dextrose-based solutions are the standard pharmaceutical vehicle for inotrope preparation 3, 2
Stability Considerations
- Dobutamine demonstrates superior overall stability compared to dopamine across all dilution vehicles, with concentration variation of only 5.76% in syringes versus 10.88% for dopamine 1
- Light exposure does not significantly affect dopamine stability when prepared in 0.9% sodium chloride over 24 hours, so light protection is not mandatory 1
- Temperature variations (including incubator conditions at 35°C) affect drug delivery through extension sets, but the choice of 5% glucose as diluent remains more important than light or temperature control 1
Practical Preparation Guidelines
- When preparing inotrope infusions for continuous administration, use 5% dextrose as the primary diluent to ensure consistent drug delivery over the typical 24-hour infusion period 1
- For neonatal and pediatric patients where precise dosing is critical, the enhanced stability of 5% glucose preparations is particularly important given the small volumes and low infusion rates used 1
- Milrinone requires preparation of dilutions prior to patient administration, and should follow the same principle of dextrose-based dilution 3
Common Pitfall to Avoid
- Do not routinely use 0.9% sodium chloride (normal saline) as the primary diluent for dopamine or dobutamine infusions, as this results in measurably lower drug concentrations at the point of delivery after 24 hours, potentially leading to inadequate therapeutic effect 1