：OBJECTIVE To establish the time of
administration(iv infusion) of
metronidazole in lactate women avoid the adverse drug
reactuion of the drug to the neonate with minimal effects on the infant.METHODS Breast milk concentrations of
metronidazole and tinidazole were assayed by high performance liquid chromatography(HPLC). A high performance and rapid column PE pecosphere C18 (3μm, 3.0 mm×33 mm) was used. RESULTS The p harmacokinetic parameters( ±s ) T max, C max, T 1/2ke of metronidazole (20 mg·kg-1, n =8) and tinidazole (13 mg·kg-1, n =7) in lactati on women after infusion of a single dose were (1.7±1.0) h, (20.1 ± 5.0) μg·ml-1, (6.4±3.3) h and (1.3±0.6) h, (17 .2 ±3.1) h, (11.0±3.5) μg·ml-1 respectively. The neonate dos e ingested via breast milk of metronidazole and tinidazole were 3.02 mg·kg -1·d-1 and 2.58 mg·kg-1·d-1. Percentage of materal dose of metronidazole and tini dazole were 15.1% and 19.9%. CONCLUSIONS The postpartum women were given iv do se of 20 mg·kg-1·d-1 metronidazole and of 13 mg·kg-1·d -1 tinidazole as treatment and prophylaxis against anaerobic infection. The neonate breast feeding should be ceased in 3～4 h following iv
administration of metronidazole(20 mg·kg-1 ). Follo wing iv administration of tinidazole(13 mg·kg-1), the neonate breast fe eding should be ceased in 4～6 h.