Therapeutic amoxicillin levels achieved with oral administration in term neonates.
OBJECTIVE
The standard treatment of neonatal group B Streptococcus infection is intravenous amoxicillin for 10 days. We investigated whether effective serum amoxicillin concentrations could be reached by switching to oral amoxicillin after 48 h of intravenous administration in full-term neonates with group B Streptococcus infection.


METHODS
Over 2 years, we included 222 full-term neonates who had early onset group B streptococcal disease responsive to 48 h of intravenous amoxicillin, at which point they were asymptomatic and fed orally. They were switched to oral amoxicillin (300 or 200 mg/kg per day in four divided doses). Steady-state serum amoxicillin concentrations were determined 48 h later by high-performance liquid chromatography; values > or =5 mg/l were considered effective.


RESULTS
Mean gestational age was 39.32 +/- 1.5 weeks ,and mean birth weight was 3,422 +/- 533 g; 29 newborns were bacteremic. Median serum amoxicillin concentration on oral therapy was 31,.15 (range 11-118) and 25.80 (range 5-84.8) with 300 and 200 mg/kg per day, respectively. None of the infants had a concentration <5 mg/l (p < 0.001). Gastrointestinal tolerance was satisfactory; 216 patients were discharged at 5 days of age, and none was readmitted within the 3-month follow-up.


CONCLUSIONS
Early switching to the oral route in asymptomatic full-term newborns with early onset group B streptococcal disease maintained serum amoxicillin concentrations within our predefined therapeutic range (error risk<0.001). This strategy may hold potential for reducing treatment invasiveness and shortening hospital length of stay.
Gras-Le Guen
Christele
C
Pediatric and Neonatal Critical Care Division, Department of Perinatology, Hôpital Mère Enfant, Centre Hospitalier Universitaire, 38 Bd J Monnet, 44099 Nantes, Cedex, France. christele.grasleguen@chu-nantes.fr
Boscher
Cecile
C
Godon
Nathalie
N
Caillon
J
J
Denis
C
C
Nguyen
J Michel
JM
Kergueris
M Francoise
MF
Roze
J C
JC
D000284:Administration, Oral; D000658:Amoxicillin / Q000008:administration & dosage* / Q000097:blood* / Q000627:therapeutic use; D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000097:blood* / Q000627:therapeutic use; D002851:Chromatography, High Pressure Liquid; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007363:Intensive Care Units, Neonatal; D008297:Male; D013290:Streptococcal Infections / Q000188:drug therapy; D013292:Streptococcus agalactiae
D000900:Anti-Bacterial Agents; D000658:Amoxicillin