Objective: To optimize the initial administration regimens for latamoxef sodium for injection in neonatal bacterial infectious diseases by Monte Carlo simulation

so as to provide reference for rational drug use in clinic. Methods: The sensitive breakpoint of minimal inhibitory concentration (MIC) of latamoxef sodium for injection was determined by referring to the criteria of Clinical and Laboratory Standards Association formulated in 2017. Combined with the drug instructions

15 kinds of initial administration regimens were developed under different MIC. Through the application of population pharmacokinetic/pharmacodynamic model and Monte Carlo simulation of probability of target attainment (PTA) in 10

000 cases of “real patients”

the optimal initial administration regimen was optimized. Results: The sensitive breakpoint of latamoxef sodium for injection to the sensitive bacteria was MIC less than or equal to 8 μg/mL. When MIC was 1 μg/mL

PTA of all the administration regimens was more than 90%. When MIC was 2 μg/mL

PTA of the other administration regimens was more than 90% except for “40 mg/(kg·d) in two doses

50 mg/(kg·d) in two doses”. When MIC was 4 μg/mL

PTA of the 8 kinds of administration regimens was more than 90% except for “all doses for 4 times a day

80 mg/ (kg·d) in three doses

70 mg/ (kg·d) in three doses

60 mg/ (kg·d) in three doses”. When MIC was 8 μg/mL

PTA of the 2 kinds of administration regimens was more than 90% with “80 mg/(kg·d) in 4 doses

70 mg/(kg·d) in four doses”. When MIC was more than or equal to 4 μg/mL and less than or equal to 8 μg/mL

PTA showed significant difference under the same dose and different administration regimens. When MIC was less than or equal to 2 μg/mL

there was no significant difference in PTA under the same dose and different administration regimens. Conclusion: Monte Carlo simulation is used to recommend “60 mg/(kg·d) in two doses” as the initial administration regimen of latamoxef sodium for injection in neonatal bacterial infectious diseases.