Experience with amoxycillin in neonates and premature babies.

Amoxycillin, a semi-synthetic penicillin, resembles ampicillin in many respects. There is cross-resistance between the two antibiotics. Numerous Gram-positive and Gram-negative organisms are sensitive to amoxycillin at relatively low dosage. Investigations using oral amoxycillin, 50 mg/kg body weight were carried out in neonates and premature babies in the first days of life. Peak values of 38 microng/ml and 59 microng/ml at 4 1/4 hours were obtained for the neonates and premature babies respectively. The 10-hour value for the first group was 13 microng/ml and for the second 19 microng/ml. With a single dose of amoxycillin, serum levels of 0.9 microng/ml were still obtained after 24 hours. In children who received the same dose twice daily, the serum values were 6.5 microng/ml after 24 hours. The urinary excretion of amoxycillin was, on an average, 41% in 24 hours. Amoxycillin was also found in the meconoium, but the quantity in the different portions showed a large dispersion. Amoxycillin can, therefore, be recommended as an effective and well tolerated antibiotic for use in the neonatal and premature period. In general the drug should be administered 12-hourly at a dose of 50 mg/kg body weight. Only in severe illnesses is 8-hourly administration required.