Chemical Compatibility of N-Acetylcysteine After the Simultaneous Intravenous Administration of Ondansetron

This study evaluated the chemical compatibility of N-acetylcysteine (NAC) and ondansetron to simplify the treatment of acute nausea and vomiting during intravenous (IV) NAC administration. NAC is commonly used to treat acetaminophen overdose, but its 21-hour IV infusion is often interrupted for ondansetron administration, which can pose risks.

High-performance liquid chromatography with ultraviolet detection was used to quantify NAC. To simulate IV administration, a closed-circuit pump with multiple independent lines, was plumbed with Y-sites to circulate NAC at concentrations matching 30- and 100-kg loading doses and 4-mg ondansetron was pushed into the flow paths. Control lines without ondansetron were also maintained. Samples were collected at 10, 20, and 30 minutes postondansetron introduction. NAC concentrations in single-drug and combination lines were compared using an unpaired t-test with Welch's correction (p = 0.05).

The mean concentrations for the 100-kg dose were 55.23 and 55.28 mg/mL for control and with ondansetron, respectively. The 30-kg cohort included 36.38 mg/mL for control and 36.49 mg/mL with ondansetron. The results of the unpaired t-test for either weight illustrated that no statistical significance was achieved. Furthermore, the t-values of 0.2013 for 100 kg and 0.8556 for 30 kg support a less likely chance of significant difference.

Based on this experiment, ondansetron can be introduced into an NAC infusion via IV push in vitro without affecting the NAC concentration in the solution. The likelihood of IV compatibility for NAC and ondansetron could permit no infusion interruptions, reducing unnecessary risk of acetaminophen toxicity.