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 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 < 0.05.

Results: The AUC, AUC, C, 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 λ and t 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.