Pharmacokinetics of combined administration of iron dextran with meloxicam or flunixin meglumine in piglets

Objective The objective was to evaluate the pharmacokinetics of compounding non-steroidal anti-inflammatory drugs (NSAIDs) meloxicam or flunixin meglumine with iron dextran (ID) in piglets. Animal Forty piglets (8 d of age) were randomly allocated into 5 groups (8 piglets/group) and received 1 intramuscular injection in the neck of the following treatments: flunixin meglumine (2.2 mg/kg) administered alone (F) or mixed with ID (F+ID); or meloxicam (0.4 mg/ kg) administered alone (M) or mixed with ID (M+ID); or ID alone. Procedure Blood samples were collected via indwelling jugular catheters at pre-dose, and 10, 20, 30, 45, and 60 min, and 2, 4, 8, 12, 24, 36, 48, and 72 h post-treatment to determine plasma NSAIDs concentrations using liquid chromatography-tandem mass spectrometry. Pharmacokinetic parameters for plasma meloxicam and flunixin meglumine concentration-time profiles were determined for each piglet using noncompartmental analysis approaches. Statistical analyses were performed using SAS software with significance set at P < 0.05. Results The AUC(0-tlast), AUC(0-infinity), C-max, and relative bioavailability values in the M+ID and F+ID groups were lower than corresponding M and F groups. The M+ID group elimination half-life was lower, whereas lambda(z) and t(max) values were greater than the corresponding M group. Conclusion Relative bioavailability of meloxicam and flunixin meglumine were reduced when compounded with ID in the same bottle and administered to piglets. Clinical relevance Further research is warranted to evaluate if decreased NSAID exposure when compounded with ID alters analgesic efficacy or drug residue depletion.