Physical Compatibility of Nafamostat with Analgesics, Sedatives, and Muscle Relaxants for Treatment of Coronavirus Disease 2019

BACKGROUND: Severe coronavirus disease (COVID-19) may require continuous administration of analgesics, sedatives, and muscle relaxants. Nafamostat has recently been reported as a therapeutic agent for COVID-19. However, there is a lack of information on the compatibility of nafamostat with the aforementioned drug classes. This study evaluated the physical compatibility of nafamostat with these drug classes. METHODS: Nafamostat was combined with 1-3 target drugs (fentanyl, morphine, midazolam, dexmedetomidine, and rocuronium). Fifteen physical compatibility tests were conducted. Nafamostat was dissolved in 5% glucose solution; the final concentration was 10 mg/mL. All other medications were diluted in 0.9% sodium chloride to obtain clinically relevant concentrations. The power of hydrogen (pH) of all medications was measured during each test. Compatibility tests were conducted with four test solutions wherein nafamostat and the target drugs were compounded at equal volume ratios (1:1, 1:1:1, or 1:1:1:1). Visual appearance, turbidity, and pH were evaluated immediately after mixing and at 1 and 3 hours. Physical incompatibilities were defined as gross precipitation, cloudiness, appearance of the Tyndall effect, or a turbidity change of ≥0.5 nephelometric turbidity unit (NTU) based on nafamostat. RESULTS: The mean pH of nafamostat was 3.13 ± 0.03. The combination of nafamostat, fentanyl, and dexmedetomidine had the highest pH (3.39 ± 0.01; 3 hours after mixing). All drugs were compatible with nafamostat until 3 hours after admixture, with a mean turbidity value of