Antibiotic therapy for severe infections in infants and children.

In infants and children, drug absorption, distribution, metabolism, and excretion may differ considerably from these factors in adults; thus, differences also exist in therapeutic efficacy and toxicity of various antibiotics. Because of known toxicity, certain drugs--such as chloramphenicol in high doses, the sulfonamides, and tetracycline--should not be used in neonates. Antibiotic therapy should be modified in neonates because of biologic immaturity of organs important for the termination of drug action. Because of poor conjugation, inactivation, or excretion, the serum concentrations of many antibiotics may be higher and more prolonged in neonates than in older infants. Thus, the dosages of many antibiotics must be lower and the intervals between administration must be longer. The appearance of strains of ampicillin-resistant Haemophilus influenzae, the slow development of resistance to chloramphenicol among gram-negative and gram-positive bacteria, and the development of improved analytic methods to measure chloramphenicol have all resulted in the use of this drug in select cases of serious infection in children beyond the neonatal age. Third-generation cephalosporins have an important role in empiric treatment of pediatric bacterial meningitis because of their ability to penetrate the central nervous system and their effectiveness against ampicillin- or chloramphenicol-resistant Haemophilus strains and against many gram-negative bacteria in the Enterobacteriaceae group.