1. Division of Infectious Diseases, Children's Hospital and Health Center,1 and
2. Department of Pediatrics, University of California,2 San Diego, California;
3. Section of Pediatric Clinical Pharmacology and Experimental Therapeutics, Children's Mercy Hospital, and the Departments of Pediatrics and Pharmacology, University of Missouri, Kansas City, Missouri3;
4. Division of Pediatric Pharmacology and Critical Care, Rainbow Babies and Children's Hospital, and Department of Pediatrics, School of Medicine, Case Western Reserve University, Cleveland, Ohio4; and
5. Pfizer Central Research, Groton, Connecticut5