Pharmacokinetics of intranasal and intramuscular flunixin in healthy grower pigs.

Flunixin meglumine is a nonsteroidal anti-inflammatory drug approved to manage pyrexia associated with swine respiratory disease. In the United States, no analgesic drugs are approved for use in swine by the FDA, although they are needed to manage painful conditions. This study evaluated the pharmacokinetics and relative bioavailability of intranasal versus intramuscular flunixin in grower pigs. Six pigs received 2.2 mg/kg flunixin either intranasally via atomizer or intramuscularly before receiving flunixin via the opposite route following a 5-day washout period. Plasma samples were collected over 60 h and analysed using ultra-performance liquid chromatography and tandem mass spectrometry to detect flunixin plasma concentrations. A non-compartmental pharmacokinetic analysis was performed. The median Cmax was 4.0 µg/mL and 2.7 µg/mL for intramuscular and intranasal administration, respectively, while the median AUCinf was 6.9 h µg/mL for intramuscular administration and 4.9 h µg/mL for intranasal administration. For both routes, the median Tmax was 0.2 h, and flunixin was detectable in some samples up to 60 h post-administration. Intranasal delivery had a relative bioavailability of 88.5%. These results suggest that intranasal flunixin has similar, although variable, pharmacokinetic parameters to the intramuscular route, making it a viable route of administration for use in grower swine.

The pharmacokinetics of transdermal flunixin in lactating dairy goats.

Flunixin is a nonsteroidal anti-inflammatory drug approved for use in cattle to manage pyrexia associated with bovine respiratory disease, mastitis, and endotoxemia. In the United States, no nonsteroidal anti-inflammatory drugs are approved for use in goats, but analgesics are needed for management of painful conditions to improve animal welfare. The objective of this study was to evaluate the pharmacokinetics of transdermal flunixin in dairy goats to determine a milk withdrawal interval (WDI) to avoid violative residue contamination in the food supply. Six adult lactating dairy goats received 3.3 mg/kg of transdermal flunixin before milk, interstitial fluid (ISF), and blood samples were collected at various time points for 360 h. The samples were analyzed using tandem mass spectrometry to detect flunixin as well as the flunixin marker metabolite, 5-hydroxyflunixin followed by a pharmacokinetic WDI calculation using the US Food and Drug Administration tolerance limit method to propose safe residue levels in goat milk. The mean flunixin apparent plasma half-life was 21.63 h. The apparent milk half-life for 5-hydroxyflunixin was 17.52 h. Our findings provide a milk WDI of 60 h using the US Food and Drug Administration tolerance of 0.002 µg/mL (established for bovine milk) and a more conservative WDI of 96 h using a limit of quantification of 0.001 µg/mL following the extralabel use of transdermal flunixin in dairy goats.

The effect of transdermal flunixin meglumine on blood cortisol levels in dairy calves after cautery disbudding with local anesthesia.

The objective of this study was to evaluate the effect of the nonsteroidal anti-inflammatory drug transdermal flunixin meglumine (Finadyne Transdermal) on plasma cortisol, average daily weight gain, and standing and lying behavior of calves, when given at the time of disbudding combined with local anesthesia. A sedative was not used to minimize pharmacological interactions. Seventy-one female Holstein Friesian calves aged 13 ± 2 d, with an average weight of 48.9 ± 4.26 kg were enrolled in the study. All calves were randomly assigned to one of 3 treatment groups: (1) control group (CON, n = 27), (2) 1-flunixin group (1-FLU, n = 26) with a single administration of transdermal flunixin meglumine at disbudding, and (3) 2-flunixin group (2-FLU, n = 24) with 2 administrations of transdermal flunixin meglumine, the first treatment at disbudding and the second 6 h after disbudding. Although the CON group received a placebo, 1-FLU and 2-FLU received flunixin meglumine transdermally. To account for plasma cortisol changes due to manipulation and handling of the calves, a sham disbudding procedure was performed one week before disbudding took place. Sham disbudding was conducted by using a cold cautery dehorner applied to each horn bud for 10 s. Disbudding was performed in a similar way by using a hot cautery dehorner. Plasma samples were collected to measure the stress biomarker cortisol at 7 different time points. Body weights were measured 4 times in 2 wk. Standing and lying behavior was assessed via 3-dimensional accelerometer. During sham disbudding and disbudding mean plasma cortisol concentrations were 6.09 ± 2.5 ng/mL and 5.16 ± 2.8 ng/mL, respectively. Treatment tended to have an effect on plasma cortisol concentrations during sham disbudding and had an effect on plasma cortisol concentrations during disbudding. Plasma cortisol concentrations were affected by treatment 2 h after disbudding in comparison to CON group. Furthermore, there was a significant effect on plasma cortisol concentrations 6 h after disbudding in contrast to CON. A return to baseline plasma cortisol levels (initial concentrations) was not achieved in CON during disbudding. There was no statistical difference between average daily weight gain and the treatment procedure. Total lying time was not affected by treatment after disbudding. In conclusion, transdermal flunixin meglumine given at the time of disbudding combined with local anesthesia decreased concentrations of the stress biomarker cortisol, but a second dose 6 h after disbudding had no further effect on plasma cortisol levels.

Chrysin and flunixin meglumine mitigate overloaded copper-induced testicular and spermatological damages via modulation of oxidative stress and apoptosis in rats.

This study aimed to evaluate the possible protective actions of chrysin and flunixine meglumine on testicular and spermatological injuries experimentally stimulated by copper. We separated 36 male Sprague-Dawley rats into six equal groups: control, chrysin, flunixine meglumine, copper, copper +chrysin and copper +flunixine meglumine. Chrysin (50 mg/kg/bw/po), flunixine meglumine (2.2 mg/kg/bw/ip) and copper (500 mg/kg/bw/po) were administered day to day for 21 days. Copper administration caused significant morphological, physiological and biochemical alterations compared to the control group, which are as follows: production of oxidative stress, thanks to rise in testis lipid peroxidation and fall in antioxidant enzyme concentrations, decrease in sperm quality and increase in morphologic sperm abnormalities, suppression of spermatogenesis and prominent alterations in the testis histomorphology and induction of apoptosis in the testis tissues. On the other hand, compared to the copper group, treatment with chrysin or flunixine meglumine significantly attenuated these alterations. In conclusion, chrysin and flunixine meglumine have benefits such as antioxidant, antiapoptotic and anti-inflammatory against copper-induced testicular and spermatological damages in rats via the modulation of oxidative stress and apoptosis. Consequently, chrysin is a natural product which has comparable therapeutic actions to flunixine meglumine on the male reproductive system.

Pharmacokinetic/pharmacodynamic modeling of ketoprofen and flunixin at piglet castration and tail-docking.

This study performed population-pharmacokinetic/pharmacodynamic (pop-PK/PD) modeling of ketoprofen and flunixin in piglets undergoing routine castration and tail-docking, utilizing previously published data. Six-day-old male piglets (8/group) received either ketoprofen (3.0 mg/kg) or flunixin (2.2 mg/kg) intramuscularly. Two hours post-dose, piglets were castrated and tail docked. Inhibitory indirect response models were developed utilizing plasma cortisol or interstitial fluid prostaglandin E2 (PGE2) concentration data. Plasma IC50 for ketoprofen utilizing PGE2 as a biomarker was 1.2 µg/ml, and ED50 for was 5.83 mg/kg. The ED50 calculated using cortisol was 4.36 mg/kg; however, the IC50 was high, at 2.56 µg/ml. A large degree of inter-individual variability (124.08%) was also associated with the cortisol IC50 following ketoprofen administration. IC50 for flunixin utilizing cortisol as a biomarker was 0.06 µg/ml, and ED50 was 0.51 mg/kg. The results show that the currently marketed doses of ketoprofen (3.0 mg/kg) and flunixin (2.2 mg/kg) correspond to drug responses of 33.97% (ketoprofen-PGE2), 40.75% (ketoprofen-cortisol), and 81.05% (flunixin-cortisol) of the maximal possible responses. Given this information, flunixin may be the best NSAID to use in mitigating castration and tail-docking pain at the current label dose.

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 via 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 P < 0.05. Results: The AUC0-tlast, AUC0-∞, Cmax, 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 λz and tmax 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.

Objectif: L'objectif était d'évaluer la pharmacocinétique de la combinaison d'anti-inflammatoires non stéroïdiens (NSAID) méloxicam ou flunixine méglumine avec du fer dextran (ID) chez les porcelets. Animal: Quarante porcelets (âgés de 8 jours) ont été répartis au hasard en cinq groupes (8 porcelets/groupe) et ont reçu une injection intramusculaire dans le cou des traitements suivants : flunixine méglumine (2,2 mg/kg) administrée seule (F) ou mélangée avec ID (F+ID); soit du méloxicam (0,4 mg/kg) administré seul (M) ou en mélange avec ID (M+ID); ou du ID seul. Procédure: Des échantillons de sang ont été prélevés via des cathéters jugulaires à demeure à la pré-dose, et 10, 20, 30, 45 et 60 min, et 2, 4, 8, 12, 24, 36, 48 et 72 h après le traitement pour déterminer la concentration plasmatique de NSAID par chromatographie liquide-spectrométrie de masse en tandem. Les paramètres pharmacocinétiques des profils concentration-temps du méloxicam et de la flunixine méglumine plasmatiques ont été déterminés pour chaque porcelet à l'aide d'approches d'analyse non compartimentale. Les analyses statistiques ont été effectuées à l'aide du logiciel SAS avec un seuil de signification fixé à P < 0,05. Résultats: Les valeurs AUC0­tlast, AUC0­∞, Cmax et de biodisponibilité relative dans les groupes M+ID et F+ID étaient inférieures à celles des groupes M et F correspondants. La demi-vie d'élimination du groupe M+ID était plus faible, tandis que les valeurs λz et tmax étaient supérieures à celles du groupe M correspondant. Conclusion: La biodisponibilité relative du méloxicam et de la méglumine de flunixine était réduite lorsqu'ils étaient combinés avec ID dans le même flacon et administrés aux porcelets. Pertinence clinique: Des recherches supplémentaires sont nécessaires pour évaluer si une diminution de l'exposition aux NSAID lorsqu'elle est associée à une ID modifie l'efficacité analgésique ou l'épuisement des résidus de médicaments.(Traduit par Dr Serge Messier).

Development of a guar gum film with lysine clonixinate for periodontal treatments.

Periodontal pain is a public health problem derived from different conditions, including periodontal diseases, prosthetic complications, and even extractions performed by dentist. There are various treatments to control acute dental pain, being the administration of analgesics, such as Lysine Clonixinate (LC), a common practice. Unfortunately, higher and repeated dosages are usually required. The purpose of this work was to develop a prolonged release pharmaceutical form as an alternative treatment for dental pain. Hence, we conceived a film based on guar gum and loaded different concentrations of LC. We evaluated the film's appearance, brittleness, strength, and flexibility, and then chose one formulation for adequate characteristics. Subsequently, we assessed the morphology, thermal behavior, and swelling properties of the films (LC-free and -loaded). Finally, we performed the release studies of LC from the films in vitro using a simulated saliva medium and employed several mathematical models to evaluate the release kinetics. Guar gum is a natural polymer obtained from the endosperm of Cyamopsis tetragonolobus that presents properties such as biosafety, biocompatibility, and biodegradability. Thus, it represents a potential excipient for use in pharmaceutical formulations. Moreover, our results revealed that the LC-loaded film presented a high adherence, suitable swelling behavior, high LC content, and a prolonged drug release. Therefore, the LC-loaded film may be considered a potential option to be applied as an alternative to treat dental pain.

Effect of treatment of pneumonia and otitis media with tildipirosin or florfenicol + flunixin meglumine on health and upper respiratory tract microbiota of preweaned Holstein dairy heifers.

The objective of this randomized clinical study was to compare the effect of 2 antimicrobial interventions, tildipirosin or florfenicol + flunixin meglumine, used for treatment of pneumonia and extralabel treatment for otitis on health parameters and upper respiratory tract (URT) microbiota of preweaned Holstein calves. Housed preweaned Holstein heifers diagnosed with either otitis or pneumonia were assigned into 1 of 2 treatment groups, receiving a single subcutaneous injection of either 4 mg/kg of tildipirosin (TLD; n = 444) or 40 mg/kg of florfenicol combined with 2.2 mg/kg of a nonsteroidal anti-inflammatory, flunixin meglumine (FLF; n = 442). Calves were enrolled and treated on the day of diagnosis of the first case of pneumonia or otitis. If a calf had a recurrent case, the opposite drug was administered, respecting an interval of 5 d between drug injections. Blood samples for leukocyte counts were collected at 0, 2, 4, and 6 d after treatment, and rectal temperature was measured daily during the 5 d after treatment. Ear scores were observed from calves with otitis. Additionally, swabs of the URT were collected from a subset of 20 calves in each treatment group at d 0, 3, 6, 9, and 11 following enrollment for analysis of URT microbiota through next-generation sequencing of the 16S rRNA gene and quantitative PCR. Swabs were also collected from a comparative group of 20 healthy calves that did not receive any drug. No differences were observed between groups for recurrence risk of either pneumonia (TLD = 32.4%; FLF = 29.7%) or otitis (TLD = 72.7%; FLF = 73.6%). Similarly, no differences were observed for the total number of treatments for pneumonia (TLD = 1.45; FLF = 1.42) or otitis (TLD = 2.96; FLF = 3.07). On the other hand, both drugs reduced rectal temperature, ear scores, and leukocyte counts, with FLF calves having a greater reduction in rectal temperature within 4 d after treatment. Both TLD and FLF reduced the total bacterial load when compared with healthy untreated calves, but no differences were observed between treatment groups. Furthermore, compared with the untreated group, treated calves had lower mean relative abundances (MRA) of the genera Mannheimia, Moraxella, and Pasteurella within 11, 9, and 3 d after treatment, respectively; however, no significant differences were observed between TLD and FLF. On the other hand, MRA of Mycoplasma was not decreased by both treatments compared to untreated animals, and a higher MRA was observed in the TLD group during 11 d after treatment in comparison to FLF and untreated calves. Based on this data, we concluded that both drugs used in the study were effective in reducing rectal temperature, ear scores, leukocyte counts, and MRA of the genera Mannheimia, Pasteurella, and Moraxella in the URT, and calves treated with FLF had a greater reduction in rectal temperature.

Randomized controlled trial comparison of analgesic drugs for control of pain associated with induced lameness in lactating dairy cattle.

Both the economic loss and welfare implications of lameness affect the dairy industry. Currently no analgesic drugs are approved to alleviate lameness-associated pain in lactating dairy cattle in the United States. In this randomized controlled trial, 48 lactating Holsteins were enrolled to evaluate the effect of oral meloxicam and i.v. flunixin meglumine on induced lameness. Cows were allocated to 1 of 4 treatment groups (n = 12 per group): lameness and flunixin meglumine (LAME + FLU); lameness and meloxicam (LAME + MEL); lameness and placebo (LAME + PLBO); or sham induction and placebo (SHAM + PLBO). Six hours before treatment, arthritis-synovitis was induced in the distal interphalangeal joint with 20 mg of amphotericin B, whereas SHAM cows were given an intra-articular injection of an equal volume (4 mL) of isotonic saline. Cows in LAME + FLU received 2.2 mg/kg flunixin meglumine i.v. and whey protein placebo orally; LAME + MEL were administered 1 mg/kg meloxicam orally and 2 mL/45 kg sterile saline placebo i.v.; LAME + PLBO were administered 2 mL/45 kg sterile saline placebo i.v. and whey protein placebo orally; and SHAM + PLBO received 2 mL/45 kg sterile saline placebo i.v. and whey protein placebo orally. The initial treatment of MEL, FLU, or PLBO was identified as time 0 h and followed by a second dose 24 h later with data collection for 120 h. The methods used to assess analgesic efficacy were electronic pressure mat, visual lameness assessment, visual analog score, plasma cortisol concentration, plasma substance P concentration, mechanical nociception threshold, and infrared thermography imaging. Linear mixed effect modeling was the primary method of statistical analysis. Visual lameness scoring indicated a lower proportion of the FLU + LAME group was lame at the T2 h and T8 h time points in comparison to the positive controls, whereas MEL therapy resulted in a lower proportion of lame cows at the T8 h time point. Cortisol area under the effect curve was lower following FLU therapy compared with LAME + PBLO for the 0-2 h (LSM difference = 35.1 ng·h/mL, 95% CI: 6.8, 63.3 ng·h/mL), 2-8 h (LSM difference = 120.6 ng·h/mL, 95% CI: 77.2, 164.0 ng·h/mL), and 0-24 h (LSM difference = 226.0 ng·h/mL, 95% CI: 103.3, 348.8 ng·h/mL) time intervals. Following MEL therapy, cortisol area under the effect curve was lower than LAME + PLBO for both the 2 to 8 h (LSM difference = 93.6 ng·h/mL, 95% CI: 50.2, 137.0 ng·h/mL) and 0 to 24 h time intervals (LSM difference = 187.6 ng·h/mL, 95% CI: 64.9, 310.4 ng·h/mL). Analysis of data from other assessment modalities failed to discern biologically relevant differences between treatment groups. We conclude that meaningful differences were evident for visual lameness assessment and cortisol from MEL and FLU treatment versus the positive control. Further clinical research is needed toward development of a model that will create reproducible events that are more pronounced in severity and duration of lameness which can be validated as a substitute for naturally occurring lameness cases.

Effect of flunixin meglumine treatment during and after embryo transfer on the pregnancy rate in cattle.

This study aimed to determine the effect of flunixin meglumine treatment during and after the transfer of in vivo produced embryos to Angus (cows) and Holstein (cows and heifers) breeds of cattle on pregnancy rate. Holstein cows were used as donors in the study. A double dose of prostaglandin F2α was administered to the recipient animals for synchronization. Uterine flushing was performed in donors on day 7 after artificial insemination. A total of 295 transferable embryos were obtained. These embryos were transferred to Angus cows (n = 85), Holstein heifers (n = 80) and Holstein cows (n = 130). After the transfer, these animals were divided into three subgroups. The first subgroup (TI) was administered flunixin meglumine during embryo transfer, and the second subgroup (TII) was administered flunixin meglumine both during embryo transfer and on days 8 and 9 after the transfer. The third subgroup (TIII) was not administered anything and it was considered the control group. Pregnancy examination of the recipients was performed on days 30-35 after the transfer using real-time ultrasonography. The pregnancy rates after embryo transfer were found to be 43.52% in Angus cows, 42.5% in Holstein heifers, and 24.61% in Holstein cows (p < .05). When the animals were not classified according to breed, the pregnancy rates in subgroups TI, TII and TIII were found to be 29.29%, 45.10% and 29.79%, respectively (p < .05). In addition, the pregnancy rates were higher in TII and TIII subgroups of Angus cows and Holstein heifers compared to that of Holstein cows (p < .05). As a result, the pregnancy rates obtained after embryo transfer in Angus cows and Holstein heifers were found to be higher than that in Holstein cows. In addition, it was concluded that the administration of flunixin meglumine during and during/after embryo transfer has a positive effect on pregnancy rates in Angus cows and Holstein heifers.

Pharmacokinetics of transdermal flunixin meglumine and effects on biomarkers of inflammation in horses.

Flunixin meglumine is a highly efficacious nonsteroidal anti-inflammatory drug commonly used in equine medicine and especially in performance horses. Recently, a new transdermal flunixin meglumine product has been approved for use in cattle. Although not currently approved for use in the horse, the convenience of this product may prove appealing for use in horses, warranting study. Six horses were administered a single transdermal dose of 500 mg and blood and urine samples collected for up to 96 h post-administration. Serum for determination of thromboxane concentrations and whole blood samples was collected at various time and challenged with lipopolysaccharide, calcium ionophore, or methanol to induce ex vivo synthesis of eicosanoids. Concentrations of flunixin, 5-OH flunixin, and eicosanoids were measured using LC-MS/MS and non-compartmental pharmacokinetic analysis performed on concentration data. Serum concentrations of flunixin and 5-OH flunixin were above the limit of quantitation at 96 h post-administration in both serum and urine. The mean (range) for Cmax , Tmax and the terminal half-life were 515.6 (369.7-714.0) ng/ml, 8.67 (8.0 12.0) h, and 22.4 (18.3-42.5) h, respectively. Following transdermal administration, based on effects on eicosanoid synthesis, flunixin meglumine inhibited cyclooxygenase 1 and 2 and 15-lipooxygenase activity, with anti-inflammatory effects lasting for 24-72 h.

Identification and characterization of the enzymes responsible for the metabolism of the non-steroidal anti-inflammatory drugs, flunixin meglumine and phenylbutazone, in horses.

The in vivo metabolism and pharmacokinetics of flunixin meglumine and phenylbutazone have been extensively characterized; however, there are no published reports describing the in vitro metabolism, specifically the enzymes responsible for the biotransformation of these compounds in horses. Due to their widespread use and, therefore, increased potential for drug-drug interactions and widespread differences in drug disposition, this study aims to build on the limited current knowledge regarding P450-mediated metabolism in horses. Drugs were incubated with equine liver microsomes and a panel of recombinant equine P450s. Incubation of phenylbutazone in microsomes generated oxyphenbutazone and gamma-hydroxy phenylbutazone. Microsomal incubations with flunixin meglumine generated 5-OH flunixin, with a kinetic profile suggestive of substrate inhibition. In recombinant P450 assays, equine CYP3A97 was the only enzyme capable of generating oxyphenbutazone while several members of the equine CYP3A family and CYP1A1 were capable of catalyzing the biotransformation of flunixin to 5-OH flunixin. Flunixin meglumine metabolism by CYP1A1 and CYP3A93 showed a profile characteristic of biphasic kinetics, suggesting two substrate binding sites. The current study identifies specific enzymes responsible for the metabolism of two NSAIDs in horses and provides the basis for future study of drug-drug interactions and identification of reasons for varying pharmacokinetics between horses.

PHARMACOKINETICS OF ORALLY ADMINISTERED FLUNIXIN MEGLUMINE IN AFRICAN (LOXODONTA AFRICANA) AND ASIAN (ELEPHAS MAXIMUS) ELEPHANTS.

Flunixin meglumine is the most commonly used nonsteroidal anti-inflammatory drug used to treat elephants; however, no pharmacokinetic study for flunixin has yet been conducted in these species, and dosages used range widely. Pharmacokinetic parameters of flunixin were determined in African (Loxodonta africana) and Asian (Elephas maximus) elephants after single-dose oral administration of 0.8 and 1.5 mg/kg flunixin paste in each species. Elephant compliance to oral administration of banamine was occasionally challenging, especially among older, female African elephants. After administration of 0.8 mg/kg flunixin, mean serum concentrations peaked in approximately 1.3 hr at 2.1 ± 0.8 µg/ml for Asian (n = 8) and 2.8 hr at 2.5 ± 0.7 µg/ml for African (n = 8) elephants. Dosages of 1.5 mg/kg flunixin resulted in mean serum concentration peaks of 7.2 ± 1.5 µg/ml in Asian elephants (n = 7) and 4.4 ± 0.7 µg/ml in African elephants (n = 6). However, multiple-dose trials using 1.1 mg/kg flunixin resulted in peak serum concentrations that were again less in Asian than African elephants (2.7 µg/ml versus 4.4 µg/ml, respectively). Asian elephants consistently had lower time to maximal concentration, greater area under the curve, and longer mean residence times compared with African elephants. In other species, flunixin is excreted unchanged primarily via hepatic routes with small amounts in the urine. Asian elephants may engage in some level of enterohepatic recycling of flunixin, as was previously reported for phenylbutazone. This study supports that different oral dosing regimens should be used for Asian (1.0 mg/kg SID) and African (1.2 mg/kg SID) elephants, and oral administration techniques used should ensure complete dosage delivery.

Plasma, urine and tissue concentrations of Flunixin and Meloxicam in Pigs.

BACKGROUND: The objective of this study was to determine the renal clearance of flunixin and meloxicam in pigs and compare plasma and urine concentrations and tissue residues. Urine clearance is important for livestock show animals where urine is routinely tested for these drugs. Fourteen Yorkshire/Landrace cross pigs were housed in individual metabolism cages to facilitate urine collection. This is a unique feature of this study compared to other reports. Animals received either 2.2 mg/kg flunixin or 0.4 mg/kg meloxicam via intramuscular injection and samples analyzed by mass spectrometry. Pigs were euthanized when drugs were no longer detected in urine and liver and kidneys were collected to quantify residues. RESULTS: Drug levels in urine reached peak concentrations between 4 and 8 h post-dose for both flunixin and meloxicam. Flunixin urine concentrations were higher than maximum levels in plasma. Urine concentrations for flunixin and meloxicam were last detected above the limit of quantification at 120 h and 48 h, respectively. The renal clearance of flunixin and meloxicam was 4.72 ± 2.98 mL/h/kg and 0.16 ± 0.04 mL/h/kg, respectively. Mean apparent elimination half-life in plasma was 5.00 ± 1.89 h and 3.22 ± 1.52 h for flunixin and meloxicam, respectively. Six of seven pigs had detectable liver concentrations of flunixin (range 0.0001-0.0012 µg/g) following negative urine samples at 96 and 168 h, however all samples at 168 h were below the FDA tolerance level (0.03 µg/g). Meloxicam was detected in a single liver sample (0.0054 µg/g) at 72 h but was below the EU MRL (0.065 µg/g). CONCLUSIONS: These data suggest that pigs given a single intramuscular dose of meloxicam at 0.4 mg/kg or flunixin at 2.2 mg/kg are likely to have detectable levels of the parent drug in urine up to 2 days and 5 days, respectively, after the first dose, but unlikely to have tissue residues above the US FDA tolerance or EU MRL following negative urine testing. This information will assist veterinarians in the therapeutic use of these drugs prior to livestock shows and also inform livestock show authorities involved in testing for these substances.

A study to assess the correlation between plasma, oral fluid and urine concentrations of flunixin meglumine with the tissue residue depletion profile in finishing-age swine.

BACKGROUND: Flunixin meglumine (FM) was investigated for the effectiveness of plasma, oral fluid, and urine concentrations to predict tissue residue depletion profiles in finishing-age swine, along with the potential for untreated pigs to acquire tissue residues following commingled housing with FM-treated pigs. Twenty pigs were housed in groups of three treated and one untreated control. Treated pigs received one 2.2 mg/kg dose of FM intramuscularly. Before treatment and at 1, 3, 6, 12, 24, 36, and 48 h (h) after treatment, plasma samples were taken. At 1, 4, 8, 12 and 16 days (d) post-treatment, necropsy and collection of plasma, urine, oral fluid, muscle, liver, kidney, and injection site samples took place. Analysis of flunixin concentrations using liquid chromatography/tandem mass spectrometry was done. A published physiologically based pharmacokinetic (PBPK) model for flunixin in cattle was extrapolated to swine to simulate the measured data. RESULTS: Plasma concentrations of flunixin were the highest at 1 h post-treatment, ranging from 1534 to 7040 ng/mL, and were less than limit of quantification (LOQ) of 5 ng/mL in all samples on Day 4. Flunixin was detected in the liver and kidney only on Day 1, but was not found 4-16 d post-treatment. Flunixin was either not seen or found less than LOQ in the muscle, with the exception of one sample on Day 16 at a level close to LOQ. Flunixin was found in the urine of untreated pigs after commingled housing with FM-treated pigs. The PBPK model adequately correlated plasma, oral fluid and urine concentrations of flunixin with residue depletion profiles in liver, kidney, and muscle of finishing-age pigs, especially within 24 h after dosing. CONCLUSIONS: Results indicate untreated pigs can be exposed to flunixin by shared housing with FM-treated pigs due to environmental contamination. Plasma and urine samples may serve as less invasive and more easily accessible biological matrices to predict tissue residue statuses of flunixin in pigs at earlier time points (≤24 h) by using a PBPK model.

Effects of various mastitis treatments on the reproductive performance of cows.

BACKGROUND: The purpose of the study described here was to evaluate the effects of different supportive treatments - such as antioxidants, immunomodulators, and nonsteroidal anti-inflammatory drugs (NSAIDs) - in mastitic cows treated with intramammary antibiotics on the efficacy of mastitis therapy and fertility indices. Fertility indices, including time to first insemination, conception rate, time between calving and conception (open days), and number of services per conception (insemination index), were evaluated for 300 dairy cows. Sixty cows without apparent clinical signs of mastitis were assigned 100 days after calving to a Control group. Another 240 cows with clinical mastitis were systematically divided into four experimental groups (I-IV) of 60 cows each. All mastitic cows were treated with approved intramammary antibiotics in recommended doses. Cows in Group I were treated with intramammary antibiotics only. Cows in Groups II, III, and IV, received intramammary antibiotic therapy and a single injection with antioxidants, an immunomodulator (lysozyme dimer), or an NSAID (flunixin meglumine), respectively. RESULTS: The lowest treatment efficacy of mastitic quarters and cows was noted in Group I (51.6 and 53.3%; p > 0.05). The best recovery rate was noted in Group II (63.3 and 66.7%; p > 0.05), followed by Group III (58.3 and 60.9%) and Group IV (58.3 and 58.0%; p > 0.05). The above data did not differ statistically (p > 0.05). The animals with mastitis (Groups I-IV) showed prolonged time to first insemination, more open days, higher insemination index, and lower conception rate than the control cows (p <  0.05). The conception rate of healthy cows and of successfully treated cows was insignificantly lower than that of cows required prolonged antibiotic therapy. Supportive treatments improved the mastitis recovery rate compared with intramammary antibiotics only. The efficacy of mastitis treatments affected the reproduction indices: in cows requiring prolonged treatment with antioxidants, a shorter time to first insemination was needed than in other groups (p <  0.05). Fewer days open were observed between the group with antioxidants and the control group (p <  0.05). CONCLUSIONS: Clinical mastitis negatively affects reproductive indices (days open, pregnancy rate after first AI, NSC) in dairy cows. Different types of supportive medicine, such as antioxidants (vitamin C and E, and ß-carotene), lysozyme dimer, or NSAID can be useful in improving fertility in mastitis cows treated with antibiotic only. It has been proven that each supportive treatment improved antibiotics efficiency and the antibiotic combined with the antioxidants was the most effective treatment.

The effects of flunixin meglumine and hoof trimming on lying behavior, locomotion, and milk production in lame and nonlame lactating dairy cows.

Hoof trimming is used to prevent and treat lameness in dairy cows; however, hoof trimming itself increases daily time spent lying down, possibly due to discomfort. We hypothesized that treatment of lame and nonlame cows with an anti-inflammatory analgesic drug at the time of hoof trimming would mitigate discomfort, thereby improving locomotion scores and reducing post-trimming increases in lying time. We further hypothesized that drug treatment would improve post-trimming milk production. Our objective was to determine the effects of treatment with the nonsteroidal anti-inflammatory drug flunixin meglumine (2.2 mg/kg of BW) at the time of hoof trimming on locomotion, lying times, and milk production in lame and nonlame lactating dairy cows. All cows were filmed for locomotion scoring 1 d before and 1, 8, and 28 d after hoof trimming. Daily time spent standing and lying was recorded for 4 d before and 4 wk after hoof trimming, and daily milk production was recorded for 1 wk before and 8 wk after trimming. Thirty minutes before hoof trimming, an intravenous injection of flunixin meglumine (n = 34) or isotonic sterile saline solution (n = 34) was administered to each cow. Then, all cows had their hooves trimmed using the Dutch method. The same treatment was repeated 24 h after hoof trimming. Cows were categorized using baseline locomotion scores as lame (score ≥3/5) or nonlame (score <3/5). Drug treatment did not affect post-trimming changes in locomotion scores, daily lying times, or milk production. In both treatment groups, most cows had the same lameness status (lame or nonlame) at baseline and after treatment, and there was no difference between groups in the number of cows that changed lameness status over time. Lame cows (n = 21) had no significant changes in lying times over the course of the study, whereas nonlame cows (n = 47) had mean daily lying times that were significantly higher than baseline all 4 wk after trimming. Hoof trimming in nonlame cows should be scheduled for a time when increased lying behavior after trimming can be accommodated.

Nonsteroidal anti-inflammatory drugs affect the mammary epithelial barrier during inflammation.

During inflammation of the mammary gland, the blood-milk barrier, which is predominantly composed of mammary epithelial cells, loses its integrity and gradients between blood and milk cannot be maintained. Nonsteroidal anti-inflammatory drugs (NSAID) are commonly used systemically in combination with local administration of antimicrobials in mastitis treatments of dairy cows to improve the well-being of the cow during the disease. However, the knowledge about their effects on the blood-milk barrier is low. This study aimed to investigate effects of different NSAID, with different selectivity of cyclooxygenase-inhibition, on the transepithelial electrical resistance (TEER) and capacitance, cell viability, and expression of tumor necrosis factor α of bovine mammary epithelial barriers in vitro. Primary mammary epithelial cells of 3 different cows were challenged with lipopolysaccharide (LPS) from Escherichia coli with or without addition of ketoprofen (1.25 mg/mL or 4 mM), flunixin meglumine (1.0 mg/mL or 4 mM), meloxicam (0.25 mg/mL, 0.75 mg/mL, or 4 mM), diclofenac (0.75 mg/mL or 4 mM) or celecoxib (0.05 mg/mL) for 6 h. Concentrations were adapted to comparable relations of the recommended dosage for systemic application. Additionally, a similar molar concentration of all NSAID was used. Lipopolysaccharide with or without NSAID induced a decrease in TEER within 5 h, which returned to control level within 14 h. Viability of cells challenged with LPS only was not affected. However, the cell viability was decreased with increasing concentrations of NSAID and this effect was amplified with simultaneous LPS challenge. Ketoprofen at both dosages, flunixin meglumine at 1.0 mg/mL, and meloxicam at 0.75 mg/mL accelerated the recovery of TEER in comparison to LPS only (return to control level within 9 h). The comparison of NSAID effects at the same molecular quantity of 4 mM showed different effect on the barrier in which ketoprofen accelerated the recovery after LPS-induced barrier opening, whereas meloxicam and diclofenac slowed down the recovery (return to control level after 24 h). In conclusion, NSAID do not prevent the mammary epithelial barrier opening by LPS; however, ketoprofen, flunixin meglumine, and meloxicam obviously support the re-establishment of the barrier integrity. Used in mastitis therapy at an optimized dosage the tested NSAID would likely support the recovery of milk composition. However, an overdose of NSAID would likely cause tissue irritation and in turn, a delayed recovery of the barrier permeability.

Lateral flow immunoassay for 5-hydroxyflunixin based on near-infrared fluorescence molecule as an alternative label to gold nanoparticles.

A high-affinity monoclonal antibody (mAb) has been prepared and separately a gold nanoparticle (AuNP)-based and a near-infrared (NIR) fluorescence-based lateral flow immunoassay (LFA) developed for determination of 5-hydroxyflunixin residue in raw milk. The AuNP and IRDye® 800CW were used to label anti-5-hydroxyflunixin mAb to form the AuNP-mAb and NIR dye-mAb conjugates, respectively. Quantitative determination of 5-hydroxyflunixin was achieved by imaging the optical or fluorescence intensity of the AuNP-mAb and NIR dye-mAb captured on the test line. As a result, the detection limits of the AuNP-based LFA and NIR dye-based LFA were 0.82 and 0.073 ng/mL in raw milk, respectively. The considerable improvement on assay sensitivity of the NIR-based LFA can be attributed to the lower background and less antibody consumption per test than that of the AuNP-based LFA. The spiking experiment by the NIR-based LFA yielded 85.7-112.6% recovery with a relative standard deviation below 14%, indicating that it has satisfactory assay accuracy and precision. Furthermore, the analytical results of actual samples by the NIR dye-based LFA were consistent with that by instrumental analysis. Therefore, these results demonstrated that the NIR dye is an ideal alternative label to the conventional AuNP for the development of LFA for veterinary drugs in animal-origin food. Graphical abstract.

Effect of rain on absorption after transdermal application of flunixin in calves.

Flunixin is a nonsteroidal anti-inflammatory drug (NSAID) that has anti-inflammatory, anti-pyretic, and analgesic effects. Recently, a novel transdermal formulation was developed (Finadyne® Transdermal, MSD Animal Health) and is now the first NSAID registered to be administered as a pour-on product in cattle. According to the manufacturer's instructions, the pour-on product should be applied only to dry skin and exposure to rain should be avoided for at least 6 hr after application. The objective of the study was to evaluate the effect of simulated exposure to light or heavy rain on flunixin absorption and bioavailability within the first 4 hr after administration. Therefore, an isocratic HPLC method was developed to quantify flunixin concentrations in bovine serum by UV detection. Light rain decreased flunixin absorption only when rain started immediately after flunixin administration, while light rain starting more than 30 min after administration of flunixin had no effect on absorption. Absorption and bioavailability of flunixin was impacted under simulated heavy rain conditions, when exposure to rain occurred within one hour after the application of the pour-on formulation, but not later.