BASIC AND CLINICAL STUDIES ON USE OF LATAMOXEF IN NEONATES

Basic and clinical studies of latamoxef (LMOX) were carried out in neonates.In basic study, these neonates consisted of 16 mature babies and 12 premature babies.<BR>LMOX was administered at dose of 10 and 20mg/kg, either as a single intravenous injection or as a 60 minutes intravenous drip infusion.Both the mature babies and the premature babies were divided into 3 subgroups as a function of the number of days after birth (0-3, 4-7 and 8-25 days).<BR>A clinical study of LMOX was performed in 12 neonates aged between 0-35 days, consisting 6 males and 6 females.(Purulent meningitis 4 cases, septicemia 1 case, bronchopneumonia 5 cases, pertussis pneumonia 1 case, urinary tract infection 1 case),<BR>1. Serum concentration and urinary excretion<BR>(1) 10mg/kg, one shot intravenous injection<BR>In the 3 subgroups of neonates the peak serum concentrations of LMOX were found to range from 14.6 to 28.9μg/ml.Although there was no significant difference, the half-life of the drug became shorter as the age of the neonates increased, these values were 4.46, 3.85 and 3.30 hours, respectively.<BR>(2) 10mg/kg, 60 minutes intravenous drip infusion<BR>As above, the peak LMOX serum concentrations were found to range from 23.7 to 38.9μg/ml, the half-lives of the 3 subgroups were 4.83, 2.48 and 3.01 hours, respectively.And urinary excretions were ranged from 46.0 to 56.5% for 6 hours.<BR>(3) 20mg/kg, one shot intravenous injection<BR>The peak serum concentrations were found to range from 31.0-82.5μg/ml, and it was found out 3.29-15.9g/ml at 8 hours after the injection.There was a tendency for the half-life to be shorter in more mature μ subjects in 3 subgroups.<BR>(4) 20mg/kg, 60 minutes intravenous drip infusion<BR>In the 3 subgroups, the peak concentration was the level existing at the end of the intravenous drip infusion, and that showed a range of 41.8-58.6μg/ml.Half-lives were found out the significant difference to their age, these showed 4.08, 2.31 and 2.52 hours.<BR>2. Cerebrospinal fluid concentrations of LMOX<BR>Cerebrospinal fluid concentrations of LMOX were studied in 2 cases at the dose about 50mg/kg.<BR>In 1 case, that's meningitis estimated E.coil organism, the cerebrospinal fluid concentrations of LMOX were found to range from 29.0 to 49.9μg/ml in that acute state.<BR>In another case from N.meningitidis, that values were found to range 12.1 to 21.3μg/ml.These cerebrospiral levels were superior value at it's penetration ratio.<BR>3. Clinical studies<BR>The 12 cases who were clinically treated with LMOX were intravenously administered a daily dose of 40-300mg/kg, given in 2-6 divided doses.(Purulent meningitis 4 cases, septicemia 1 case, bronchopneumonia 5cases, pertussis pneumonia 1 case, urinary tract infection 1 case).The overall efficacy rate in these 12 cases was 91.7%.The causative organism had been identified in 9 of these patients (E.coli in 3 cases, K.pneumoniae in 2 cases, S.pneumoniae in 2 cases, N.meningitidis, group B Streptococcus, in 1 case, respectively).All those organism disappeared from the culture of specimens after the therapy.The bacteriological efficacy rate was 100%.<BR>4. Conclusion<BR>When LMOX was administered at 20mg/kg, almost all serum concentration maintained 10μg/ml forup to 6-8 hours after the administration, at 10mg/kg it maintained 6μg/ml to 6 hours, and in viewof the half-lives' values and the bacterial activity of LMOX, it can be concluded that, in the infections of moderate state, it should be appropriate to administer this drug in a dose of 20mg/kg, given 3 times a day.Moreover, it may possible to give 2 times to neonates who are 3 days old or less.<BR>In the such serious infections as meningitis and septicemia, the causative organism should be established. Based on those findings, we can be confident of obtaining good results if LMOX is administered intravenously in a dose of 50mg/kg, 4 times a day.