Metronidazole pharmacokinetics during rapid growth in turkeys – relation to changes in haemodynamics and drug metabolism. Issue 4 (27th January 2016)

• Record Type: Journal Article
• Authors: Świtała, M.; Poźniak, B.; Pasławska, U.; Grabowski, T.; Motykiewicz‐Pers, K.; Bobrek, K.
• Is Part Of: Journal of veterinary pharmacology and therapeutics. Volume 39:Issue 4(2016)
• Page Start: 373
• Page End: 380
• Publication Date: 2016-01-27
• Subjects: Veterinary pharmacology -- Periodicals; Therapeutics -- Periodicals; 636.0895105
• DOI: 10.1111/jvp.12283
• Languages: English
• ISSNs: 0140-7783

Abstract

Abstract : Whereas interspecies variation in pharmacokinetics is a commonly investigated issue, variations in drug kinetics within a species are less documented. The aim of the study was to assess the influence of age‐related changes in haemodynamics on the pharmacokinetics of metronidazole (MTZ) and its hydroxy metabolite (MTZ‐OH) in turkeys. MTZ was administered intravenously and orally at a dose of 25 mg/kg. Plasma drug and metabolite concentrations were assessed by high‐performance liquid chromatography, and pharmacokinetic parameters were calculated by noncompartmental analysis. Haemodynamic parameters (heart rate, stroke volume, cardiac output) were assessed by echocardiography and extraction ratio for MTZ was calculated based on total body clearance (ClB ). Between the 5th and 15th week of age, ClB of MTZ decreased from 3.6 to 1.2 mL/min/kg causing a twofold increase in the mean residence time (MRT) and elimination half‐life (T1/2el ). The MTZ‐OH production decreased threefold and its MRT and T1/2el increased. Although heart rate significantly decreased with age, cardiac output increased. Extraction ratio was low in all age groups. It is concluded that significant age‐dependent decrease in ClB of MTZ in turkeys resulted from decreased perfusion of the clearing organs and their reduced metabolic capacity. This phenomenon is probably species specific and may apply to other therapeutic agents.