Zimeta is the only FDA approved NSAID for treatment of Pyrexia (fever) in horses.
Dipyrone is the only centrally acting NSAID that is FDA approved for horses.
Dipyrone half-life 3.94 hours
Only NSAID with a 24 hour USEF and AQHA withdrawal with a med form and not considered a stacking NSAID
 
USEF Press Release on Zimeta use https://www.usef.org/media/press-releases/us-equestrian-announces-requirements-for-use-of
AQHA Press Release on Zimeta use https://www.aqha.com/-/zimeta-approved-by-aqha-as-a-therapeutic-medication