title: Pharmacokinetics of ceftriaxone after intravenous infusion and intramuscular injection.
abstract: The pharmacokinetics of ceftriaxone were evaluated in eight adults after doses of 1 g administered by intravenous infusion and 1 and 0.5 g administered by intramuscular injection. Mean peak plasma concentrations were 168 micrograms/ml for 1 g given intravenously, 81 micrograms/ml for 1 g given intramuscularly, and 46 micrograms/ml for 0.5 g intramuscularly. Plasma concentrations were similar by both high pressure liquid chromatographic and microbiologic methods. The plasma half-lives were 7.6 and 8.3 hours, respectively, for the intravenous infusion and intramuscular injection. Plasma concentrations were equal for the 1 g intravenous and intramuscular routes by 2.5 hours. Plasma concentrations exceeded the minimal inhibitory concentrations (MICs) of most aerobic gram-positive and gram-negative organisms with the exception of Pseudomonas aeruginosa and Acinetobacter species for 24 hours. Urinary concentrations exceeded 100 micrograms/ml for 24 hours for the 1-g doses and for 12 hours for the 0.5-g dose. Urinary recovery of ceftriaxone within 24 hours was 40 percent for intravenous infusion and 33 and 34 percent for the intramuscular injection. A single 1-g dose daily will exceed the MICs of most staphylococcal and streptococcal species and Enterobacteriaceae for 12 to 24 hours.
mesh_terms: D000328:Adult; D001419:Bacteria / Q000187:drug effects; D002439:Cefotaxime / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D002443:Ceftriaxone; D006207:Half-Life; D006801:Humans; D007263:Infusions, Parenteral; D007275:Injections, Intravenous; D007668:Kidney / Q000378:metabolism; D007700:Kinetics; D008297:Male
chemical_list: D002443:Ceftriaxone; D002439:Cefotaxime