Pharmacokinetics of ibuprofen after intravenous and oral administration and assessment of safety of administration to healthy foals
Breuhaus, B.A.; DeGraves, F.J.; Honore, E.K.; Papich, M.G.
American Journal of Veterinary Research 60(9): 1066-1073
1999
ISSN/ISBN: 0002-9645 PMID: 10490073 Document Number: 499073
Ibuprofen (10 or 25 mg/kg) was administered i.v. and orally (via nasogastric tube) to 7 healthy 5- to 10-week-old foals. Blood samples were obtained between 0 and 480 min after ibuprofen administration for determination of serum concentrations. The foals were then given ibuprofen (25 mg/kg, orally, every 8 h) as a paste for 6 days and killed on the subsequent day. Serum and urine were obtained before and after the 6-day period. Half-life of elimination (Kel t1/2) of i.v.-administered ibuprofen (at 10 and 25 mg/kg, respectively), was 79 and 108 min, maximal serum concentration (CMAX) was 82 and 160 micro g/ml, and clearance was 0.003 and 0.002 litres kg-1 min-1, respectively. At the higher dosage, clearance was significantly lower and CMAX was significantly higher. Ibuprofen given via nasogastric tube resulted in Kel t1/2 of 81 and 100 min and CMAX of 22 and 52 micro g/ml at the 10 and 25 mg/kg dosages, respectively. The absorption half-life was 13 min, and bioavailability ranged from 71 to 100%. Foals remained healthy during oral administration of ibuprofen. Serum urea nitrogen, creatinine, and L-iditol dehydrogenase values increased significantly, and gamma -glutamyltransferase (GGT) activity and osmolality decreased, but all measurements remained within reference ranges. Urine GGT activity doubled. Necropsy did not reveal gross or histological renal lesions attributable to ibuprofen. Acute gastric ulcers were evident in 1 foal, although clinical signs of ulcers were not observed. It is concluded that ibuprofen can be given safely to healthy foals at dosages <=25 mg/kg every 8 h for up to 6 days.