Jr. Wilcke et al., PHARMACOKINETICS OF KETOPROFEN IN HEALTHY FOALS LESS-THAN 24 HOURS OLD, American journal of veterinary research, 59(3), 1998, pp. 290-292
Objective-To determine pharmacokinetic variables that describe disposi
tion of ketoprofen after its IV administration to foals < 24 hours old
. Animals-8 healthy foals (1 male and 5 females); mean age, 12.5 (rang
e, 8.5 to 17) hours at time of dose administration. Procedure-Ketoprof
en was administered IV to foals at a dosage of 2.2 mg/kg of body weigh
t. Ketoprofen concentration in plasma samples was analyzed, using high
-performance liquid chromatography. Concentration versus time profiles
were analyzed according to standard pharmacokinetic techniques. Blood
samples were obtained from foals by jugular venipuncture at defined t
imes during a 48-hour period. Samples were centrifuged, and plasma was
frozen at -70 C until analyzed. One-, two-, and three-compartment ana
lyses were conducted. The most appropriate model was determined by use
of Akaike's information criterion analysis. Results-Plasma concentrat
ion versus time profiles were best described, using a two-compartment
open model. Clearance (normalized for body weight) was significantly l
ower than that determined for adult horses. Volume of distribution (no
rmalized for body weight) was larger than that determined for adult ho
rses. Mean (harmonic) plasma half-life for healthy foals < 24 hours ol
d was 4.3 hours. Clinical Relevance-Although additional factors, such
as dehydration or sepsis, must be considered on a case-by-case basis,
the dose of ketoprofen administered to foals < 24 hours old should be
different from the dose administered to adult horses. Under similar cl
inical circumstances, doses in foals should be increased by as much as
1.5 times to produce comparable therapeutic concentrations; longer do
se intervals, based on clinical response, would be necessary to avoid
drug toxicity.