Pharmacokinetics and safety of oral administration of meloxicam to foals.
Authors: Raidal S L, Edwards S, Pippia J, Boston R, Noble G K
Journal: Journal of veterinary internal medicine
Summary
# Pharmacokinetics and Safety of Oral Meloxicam in Foals Meloxicam's safety and effectiveness have been established in adult horses, yet neonatal physiology raises questions about whether these findings translate to young foals; this 2013 study addressed that gap by investigating both single and repeated-dose pharmacokinetics in twenty light-breed foals under six weeks of age. Using two cohorts—one for pharmacokinetic modelling and one for safety evaluation—the researchers administered 0.6 mg/kg doses orally and monitored plasma concentrations, clearance rates, and adverse effects over three weeks of repeated dosing. Notably, whilst peak plasma concentrations and time-to-peak resembled adult horses, foals eliminated meloxicam far more rapidly with an elimination half-life of just 2.48 ± 0.25 hours compared to longer values in mature animals, meaning dosing intervals may need adjustment to maintain therapeutic levels. The 0.6 mg/kg every-12-hours regimen proved safe and efficacious in foals with no drug accumulation, and intriguingly, even high-dose administration (1.8 mg/kg twice daily for seven days) produced no adverse effects—a starkly different safety profile than reported in adult horses at equivalent or lower multiples of the standard dose. For equine practitioners, this research supports confident use of meloxicam in foals at the recommended 0.6 mg/kg q12h dosing, with the reassuring finding that neonates appear more tolerant of this NSAID than their adult counterparts, though the shortened half-life underscores the importance of maintaining proper dosing intervals.
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Practical Takeaways
- •Meloxicam 0.6 mg/kg orally every 12 hours is an effective and safe analgesic option for foals under 6 weeks of age, providing therapeutic plasma concentrations without drug accumulation
- •The rapid clearance in foals means shorter dosing intervals may be needed compared to adult horses, but twice-daily dosing provides adequate therapeutic coverage
- •Foals tolerate meloxicam better than adult horses, allowing for confident use in neonatal pain management without the gastrointestinal or renal concerns that necessitate caution in adults
Key Findings
- •Meloxicam elimination half-life in foals (2.48 ± 0.25 hours) is much more rapid than in adult horses despite similar peak plasma concentrations
- •Oral dose of 0.6 mg/kg every 12 hours was well tolerated in foals for up to 3 weeks with no plasma drug accumulation
- •High-dose meloxicam (1.8 mg/kg twice daily for 7 days) produced no adverse effects in foals, contrasting with adverse effects observed in adult horses at higher dose rates
- •Foals appear more resilient to meloxicam adverse effects compared to adult horses, contrary to the pattern seen with other NSAIDs