Understanding the stability of dopamine and dobutamine over 24 h in simulated neonatal ward conditions

OBJECTIVES: Our objectives were to investigate the possible effects of temperature and light on the stability of dopamine and dobutamine continuous infusions over 24 h when prepared in a variety of dilution vehicles. METHODS: Syringe-driver infusion apparatuses were set up for dopamine and dobutamine diluted with either 0.9% sodium chloride (NaCl) or 5% glucose delivering 3 and 5 μg/kg/min, respectively, via 206-cm extension sets. All infusions were prepared for a neonate weight of 1 kg. Infusions were run over 24 h with approximately half the tubing within an incubator set at 35 °C. Cyclic voltammetry was used to monitor the concentration of the inotrope within the syringe and at the end of the extension set, both initially and after 24 h. RESULTS: The variation in the concentration of dopamine and dobutamine in the vials (n = 6) was 3.58 and 1.22%, respectively. This variation increased to 10.88% for dopamine and 5.76% for dobutamine in the syringe. After 24 h, a significant reduction in the concentration of dopamine was observed at the end of the extension set when prepared in 0.9% NaCl versus 5% glucose (p < 0.001; n = 6-7) and in dobutamine when prepared in 0.9% NaCl (p < 0.001; n = 6-7). No differences in the concentration of dopamine prepared in 0.9% NaCl were observed after 24 h in light-exposed and light-protected extension sets (n = 6-7). CONCLUSIONS: Dobutamine is more stable in dilution vehicles than dopamine, and inotropes are more stable in the 5% glucose dilution vehicle than in 0.9% NaCl. Such findings will provide guidance on the choice of inotropes