title: Comparative pharmacokinetics of antibiotics in newborn calves: chloramphenicol, lincomycin, and tylosin.
abstract: The pharmacokinetics of 3 antibiotics--chloramphenicol, lincomycin, and tylosin--were determined in newborn calves. The kinetic determinations, using 2-compartment open models, were made at increasing ages from 1 day to 42 days and compared with those made from 9-month-old calves. Although all 3 antibiotics require a degree of hepatic metabolism, there were marked differences in the development of elimination processes for the individual drugs. Elimination of tylosin, which was slow in the calves at birth, increased rapidly and was equal to that in older calves by the end of 1 week. Lincomycin elimination was not markedly reduced in calves at birth. Chloramphenicol elimination was slow in calves at birth and only by 4 to 6 weeks attained the rate found in older calves. Dosage adjustments would not be required for the antibiotics tylosin or lincomycin when given to newborn calves, but may be necessary for chloramphenicol given to calves before they are 4 to 6 weeks old.
mesh_terms: D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D000900:Anti-Bacterial Agents / Q000008:administration & dosage; D002417:Cattle / Q000378:metabolism*; D002701:Chloramphenicol / Q000378:metabolism*; D006207:Half-Life; D007668:Kidney / Q000378:metabolism; D007700:Kinetics; D007933:Leucomycins / Q000378:metabolism*; D008034:Lincomycin / Q000378:metabolism*; D008099:Liver / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D007933:Leucomycins; D002701:Chloramphenicol; D008034:Lincomycin