title: Bactericidal activity of clarithromycin and its 14-hydroxy metabolite against Haemophilus influenzae and streptococcal pathogens.
abstract: The serum bactericidal activity of clarithromycin in six normal human volunteers was determined after oral doses of 500 mg. The mean plasma levels of clarithromycin plus 14-hydroxy clarithromycin were 2.11 micrograms/mL after the second dose and 4.36 micrograms/mL after the sixth dose. The mean serum bactericidal titer against Haemophilus influenzae after the second dose was 1:8 and after the sixth dose 1:16 when unheated serum was used. Similar values were obtained when serum to which clarithromycin and 14-hydroxy clarithromycin was added was tested. Mean serum bactericidal titers against H. influenzae determined in Haemophilus test broth or heated serum were 1:2 and 1:4, respectively. Against Streptococcus pneumoniae and Streptococcus pyogenes, there was greater than 1:16 serum bactericidal levels at 12 hours after the sixth dose of clarithromycin.
authors.affiliation: Department of Medicine, College of Physicians & Surgeons, Columbia University, New York, New York 10032.
authors.forename: J W
authors.initials: JW
authors.lastname: Gu
authors.forename: B E
authors.initials: BE
authors.lastname: Scully
authors.forename: H C
authors.initials: HC
authors.lastname: Neu
mesh_terms: D000284:Administration, Oral; D017291:Clarithromycin / Q000031:analogs & derivatives; D004917:Erythromycin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D006193:Haemophilus influenzae / Q000187:drug effects*; D006801:Humans; D015610:Serum Bactericidal Test / Q000379:methods; D013291:Streptococcus / Q000187:drug effects*; D013296:Streptococcus pneumoniae / Q000187:drug effects; D013297:Streptococcus pyogenes / Q000187:drug effects
chemical_list: C056228:14-hydroxyclarithromycin; D004917:Erythromycin; D017291:Clarithromycin