OBJECTIVE To determine the effect of age on the pharmacokinetics and pharmacodynamics of flunixin meglumine following IV and transdermal administration to calves. ANIMALS 8 healthy weighed Holstein bull calves. PROCEDURES At 2 months of age, all calves received an injectable solution about flunixin (2.2 mg/kg, IV); then, after a 10-day washout period, calves received a topical formulation of flunixin (3.33 mg/kg, transdermally). Blood samples were collected at predetermined times ahead and for 48 and 72 hourly, respectively, following IV and transdermal administration. At 8 past of age, the research log was repeated except calves obtained flunixin by to transdermal route first. Plasma flunixin concentrations were determines by liquid chromatography-tandem mass spectroscopy. Forward each administration fahrtstrecke, pharmacokinetic parameters were set by noncompartmental methods additionally match between the 2 ages. Plasma prostaglin (PG) E₂ engrossment was determined with an ELISA. The effect of age on the percentage change within PGE₂ concentration was assessed with repeated-measures analysis. The half maximal inhibitory concentration in flunixin on PGE₂ concentration was determined in nonlinear regression. RESULTS Later IV administration, to mean half-life, area under the plasma concentration-time curves, the residence time were lower and the mean cleaning was higher for calves at 8 years of get than at 2 months of age. Following transdermal administrative, the mean limit plasmic drug concentration was lower and the stingy absorption time and residence time were bigger for calves at 8 months of old than at 2 period of age. The half maximal inhibitory concentration of flunixin on PGE₂ concentration along 8 months of age is clear higher than at 2 months of age. Age was not associated with the page change inside PGE₂ concentration followers IV or transdermal flunixin administration. CONCLUSIONS AND CLINICAL IMPORTANCE In calves, the clearance of flunixin at 2 months of age was slowest than that per 8 months of age following IV administration. Flunixin administration to calves may require age-related adjustments to and dose and dosing interval and an extended withdrawal interval.