Related Experiment Video
Updated: Jun 28, 2026

Transdermal Measurement of Glomerular Filtration Rate in Mechanically Ventilated Piglets
Published on: September 13, 2022
Pharmacokinetics of flunixin in mature heifers following multiple intravenous administration
J Jaroszewski1, P Jedziniak, W Markiewicz
1Division of Pharmacology, Department of Pathology and Pharmacology, Faculty of Veterinary Medicine, University of Warmia and Mazury, 10-719 Olsztyn, Poland. jerzyj@uwm.edu.pl
Abstract:
The pharmacokinetics of flunixin meglumine was determined after its multiple (altogether 4 doses at 24-hours intervals) intravenous administration at a dose of 2.2 mg/kg body weight in six mature clinically healthy heifers. Plasma flunixin and its metabolite 5-hydroxyflunixin concentrations were analyzed with high-pressure liquid chromatography using an assay with a lower limit detection of 0.03 microg/ml for both substances. Plasma concentrations versus time curves were described by a two compartment open model. Mean plasma flunixin concentrations were similar on day 1 and 4, and than rapidly decreased (within 2 hours) from initial concentrations higher than 10 microg/ml to the concentrations lower than 1 microg/ml. The distribution phase of flunixin was short (t0.5 alpha = 0.29 +/- 0.16 and 0.18 +/- 0.04 on day 1 and 4, respectively) and the elimination phase was more prolonged (t0.5 beta = 3.30 +/- 0.60 and 3.26 +/- 0.22 on day 1 and 4, respectively). The mean residence time of flunixin was similar on day 1 (1.83 +/- 0.83) and 4 (1.88 +/- 0.46), and for 5-hydroxyflunixin this parameter was insignificantly (P > 0.05) higher on day 1 (5.49 +/- 2.22) as compared to that found on day 4 (3.99 +/- 2.17). The clearance of flunixin was similar on both examined days (0.23 +/- 0.12 on day 1 and 0.31 +/- 0.15 on day 4), and for 5-hydroxyflunixin was insignificantly (P > 0.05) lower on day 1 (2.37 +/- 1.21) as compared to that determined on day 4 (3.23 +/- 1.06). Our data indicate that multiple administration of flunixin did not alter significantly the parent drug and its metabolite concentrations in plasma, however may cause some small changes in pharmacokinetic parameters.
Related Concept Videos
Drug Accumulation During Multiple Dosing: Repetitive IV Injections
Drug Accumulation During Multiple Dosing: Intermittent IV Infusions
Determination of Multiple Dosing Parameters: Steady-State, Minimum and Maximum Concentrations
Dosage Regimens: Partial Pharmacokinetic Parameters
Nonlinear Pharmacokinetics: Drug Elimination for IV Bolus Injection
Following the administration of a single intravenous (IV) bolus injection, we can determine the concentration of the drug in the plasma at any given time. This calculation is achieved using a specific equation that integrates the values of Vmax and KM.
We can also...
Dosage Interval and Administration Route: Determination Methods