Pain Management for Gastrointestinal Conditions in Exotic Animals

Gastrointestinal (GI) disorders are very common in exotic animals, such as reptiles, birds, mammals, and can be extremely painful. This review aims to provide the reader with a better understanding of the different pain mechanisms and manifestations across orders and species in order to provide the most updated information on pain recognition and management for GI conditions in exotic animals.

Pain management in pet guinea pigs (Cavia porcellus): a review of limitations of current knowledge and practice

OBJECTIVE

To describe recent evidence-based and peer-reviewed literature on the topic of pain assessment and pain management in guinea pigs in a systematic review. To consider impacts of current practice on guinea pig welfare and to identify areas in need of further research.

DATABASES USED

ScienceDirect, PubMed and CAB abstracts along with relevant information from books and ebooks were searched. Terms used were guinea pigs, cavies, Cavia porcellus, pain, surgery, surgical procedures, grimace, dental, bloat, analgesia, non-steroidal anti-inflammatories and opiates.

CONCLUSIONS

There are few studies available in the areas of pain assessment and pain management in guinea pigs. Grimace scales and in-clinic pain assessment scales are available for other species but have not been developed for guinea pigs. Doses of analgesic drugs are extrapolated from other species or used from anecdotal evidence in the absence of validated values. The specified dose for the only UK licenced analgesic drug for guinea pigs (meloxicam) is significantly lower than doses suggested in the reviewed literature which may have a negative impact on the welfare of this species. To improve the welfare of guinea pigs, further research into the pharmacokinetic (PK) and pharmacodynamic (PD) properties of analgesic drugs specific to this species are required. Further research into the development and validation of pain assessment methods is also indicated to promote better welfare of this species.

Comparison between Carprofen and Meloxicam for Post-Neutering Pain Management in Pet Rabbits

Surgical neutering in pet rabbits is common practice to prevent reproduction and associated health issues. Adequate postoperative pain management is crucial for recovery, yet effective methods in clinical settings remain underexplored. This study compared the analgesic effects of carprofen and meloxicam in pet rabbits undergoing surgical neutering. Fifty rabbits of varied demographics were included, with pain assessed using the Centro Animali Non Convenzionali Rabbit Scale (CANCRS). Rabbits were allocated to receive postoperative 2 mg kg-1 carprofen or 1 mg kg-1 meloxicam by subcutaneous injection. Anesthesia was induced with an intramuscular combination of ketamine (20 mg kg-1), medetomidine (0.4 mg kg-1), and butorphanol (0.2 mg kg-1), and ovariectomy or orchiectomy were performed. The CANCRS scale was used to assess pain by evaluating the rabbit preoperatively, 6 h postoperatively, and at three time points the following day. Times of return to spontaneous feeding and fecal production were also recorded. No statistically significant difference was found between treatment groups based on CANCRS scores and resumption of food intake and fecal output. No clinically detectable adverse effects were noted. While limitations include the use of a single pain assessment scale and the absence of a placebo control group, the results suggest that both carprofen and meloxicam can be viable options in clinical practice. Further research utilizing diverse pain assessment methods is warranted to enhance understanding and optimize pain management strategies for rabbits undergoing surgical procedures.

Pharmacokinetics of the analgesic and anti-inflammatory drug meloxicam after administration of multiple doses to nursehound sharks (Scyliorhinus stellaris)

OBJECTIVE

To determine the pharmacokinetics of meloxicam in the nursehound shark (Scyliorhinus stellaris) during multiple dose administration.

STUDY DESIGN

Prospective experimental trial.

ANIMALS

A total of eight clinically healthy adult nursehounds (four males, four females).

METHODS

Meloxicam was administered intramuscularly at a dose of 1.5 mg kg-1 once daily for 7 days. Blood samples were collected from the caudal vein for pharmacokinetic analysis at 2.5 hours and 24 hours after drug administration. After a 4 week washout period, meloxicam was administered orally at the same dose at 12 hour intervals for three repeated doses. Blood samples were collected at 1, 2, 4, 6, 8, 12, 24, 36 and 48 hours after the first administration. Sharks were visually monitored during each study and 4 weeks afterwards for side effects or signs of toxicity. Time required to achieve steady state was assessed by visual inspection and statistical comparison of peak and trough concentrations using a Friedman test; comparison between sexes was performed using a Mann-Whitney U test and p-value was set at 0.05.

RESULTS

No animal died or showed clinical signs of toxicity during the study. Meloxicam administered orally did not produce detectable concentrations in plasma. After intramuscular administration, steady state was achieved after five doses, and mean trough and peak plasma concentrations at steady state were 1.76 ± 0.21 μg mL-1 and 3.02 ± 0.23 μg mL-1, respectively. Mean peak concentration accumulation ratio was 2.50 ± 0.22.

CONCLUSIONS AND CLINICAL RELEVANCE

This study shows that intramuscular posology produces plasma concentrations considered therapeutic for other species. However, meloxicam was not detected in plasma after oral administration. These results suggest that meloxicam administered intramuscularly may be a useful non-steroid anti-inflammatory drug in nursehound sharks. Further pharmacodynamic studies are needed to fully evaluate its clinical use in this species.

Measurement of Cyclooxygenase Products in Plasma as Markers for Inhibition of Cyclooxygenase Isoforms by Oral Meloxicam in New Zealand White Rabbits (Oryctolagus cuniculus )

Pain management in rabbits is a challenging task that is complicated by the rabbit's ability to hide signs of distress and the limited pharmacologic data available for this species. Pharmacokinetic data has shown that in rabbits, meloxicam, a nonsteroidal anti-inflammatory NSAID, reaches plasma concentrations that are known to provide analgesia in dogs and cats; these concentrations could theoretically alleviate pain in rabbits. However, the inhibitory effects of meloxicam on cyclooxygenase (COX) isoforms have not been studied in rabbits. In this study, we measured the products of COX-1 and COX-2 after the oral administration of a single 1 mg/kg dose of meloxicam to New Zealand White rabbits (n = 6). Blood samples were collected before drug administration (T0) and then at predetermined time points over 48 h. Plasma prostaglandin E₂ (PGE₂ ) and thromboxane (TxB₂) concentrations were measured as surrogate markers for COX-1 and COX-2, respectively, by using commercial ELISA kits. After meloxicam administration, both TxB₂ and PGE₂ plasma concentrations fell significantly below baseline, with maximal mean reductions to 80% and 60% of baseline at 8 h, respectively. The reduction in PGE₂ concentrations was followed by a significant increase that moved its mean plasma concentrations toward baseline between 8 and 24 h. Adverse effects such as lethargy, inappetence, or changes in fecal production were not observed in any rabbits. In conclusion, meloxicam appeared to significantly inhibit both COX-1 and COX-2 with a time course similar to previously reported meloxicam plasma concentration-time profiles in rabbits. Our data suggest that a dosage of 1 mg/kg given orally could provide analgesia to rabbits, but a more frequent dosing interval than the currently recommended daily dosing may be required to maintain clinical efficacy.

Examination of the pharmacokinetics and differential inhibition of cyclooxygenase isoenzymes in New Zealand white rabbits (Oryctolagus cuniculus) by the Non-Steroidal anti-inflammatory Robenacoxib

Effective rabbit analgesia is challenging, and there are few studies available on the newer COX-2 selective NSAIDs, such as robenacoxib. This study aimed to establish the pharmacokinetics of oral and subcutaneous robenacoxib, describe its inhibitory actions on COX enzymes, and develop dosing, using six healthy New Zealand white rabbits. Pharmacokinetics were determined from plasma concentrations after oral administration of robenacoxib (0.83-0.96 mg/kg) and also after subcutaneous administration (2 mg/kg). The inhibitory actions of robenacoxib were evaluated by measuring plasma concentrations of thromboxane B₂ (TBX₂ ) and prostaglandin E₂ (PGE₂ ) as surrogate markers of cyclooxygenase enzyme isoform inhibition. The mean maximum concentration for oral and subcutaneous administration was 0.23 μg/ml and 5.82 μg/ml, respectively. Oral robenacoxib administration did not demonstrate a significant difference between any time point for PGE₂ or TBX₂ , though subcutaneous administration did for both. There was no significant difference in PGE₂ or TBX₂ concentrations at any time point when comparing subcutaneous versus oral routes. Although the results support that plasma robenacoxib exceeds the therapeutic levels compared to dogs and cats, there was little significance in the difference in the changes associated with COX-1 and COX-2 inhibition. Further studies are warranted to determine appropriate dosing, safety, and efficacy in rabbits.

PHARMACOKINETICS OF MELOXICAM AFTER SINGLE ORAL AND INTRAMUSCULAR ADMINISTRATION IN CHINA ROCKFISH (SEBASTES NEBULOSUS)

Fish species are important for various purposes including aquaculture stock and display animals, but there are significant gaps in the medical knowledge regarding pharmacological parameters and effective pain management. Meloxicam is a nonsteroidal anti-inflammatory drug (NSAID) that has been studied in few teleost species and with several administration routes. However, these species were typically freshwater or euryhaline fish, and evaluation in marine species is lacking. The pharmacokinetic properties of meloxicam were determined in nine adult China rockfish (Sebastes nebulosus), presumed healthy based on physical examination and benign medical histories. Based on a pilot study, China rockfish were given 1 mg/kg meloxicam via IM injection in the epaxial musculature, and, after a 48-h washout period, 1 mg/kg meloxicam was given by PO gavage. Blood samples were collected from the caudal vein at baseline and at nine time intervals over a 48-h time period following administration of meloxicam. Plasma meloxicam concentrations were determined by reverse phase high-performance liquid chromatography, and noncompartmental analysis was performed. The mean peak plasma concentration after IM injection was 4.9 µg/ml, and the mean terminal half-life was 5.0 h. The mean peak plasma concentration after PO administration was 0.07 µg/ml. Based on these findings, IM injected meloxicam reaches plasma levels consistent with therapeutic concentrations in select mammals, and peak levels were maintained for ≤12 h. Single-dose PO administration failed to achieve similar concentrations, and clinical practicality is unknown. Further studies evaluating NSAID multidose regimes and their pharmacodynamic effects may provide additional dosing information.

Treatment of Pain in Rabbits

Rabbits occupy facets of veterinary medicine spanning from companion mammals, wildlife medicine, zoologic species, and research models. Therefore, analgesia is required for a variety of conditions in rabbits and is a critical component of patient care. Considerations when selecting an analgesic protocol in rabbits include timing of administration, route of administration, degree or anticipated pain, ability to access or use controlled drugs, systemic health, and any potential side effects. This review focuses on pharmacologic and locoregional management of pain in rabbits and emphasizes the need for further studies on pain management in this species.

Evaluation of sources cited by an exotic animal formulary for supporting drug dosages and reference intervals in mammals

OBJECTIVES

Formularies are intended to simplify clinical decision-making by collecting evidence-based information on drugs and their dosages. This study assessed the characteristics of sources used to support drug dosages and reference intervals for mammals in a specific exotic animal formulary, and how the sources had changed over five editions.

METHODS

Each reference supporting drug dosages and reference intervals in the sections for ferrets, rabbits, rodents, hedgehogs and miniature pigs in all five editions of the formulary was evaluated and classified by two independent investigators in terms of the type of source cited. Univariable and multi-variable logistic regression models were built to evaluate changes between editions and sections.

RESULTS

In total, 1338 references supporting drug dosages and 180 references supporting reference intervals were included from all editions of the formulary. Primary sources were cited by 525 (39.2%) and 39 (21.7%) of the drug and reference interval references, respectively. For drug dosages, the current edition of the formulary (2018) cited a higher proportion of primary rather than secondary sources compared with the first edition (odds ratios 3.4, 95% confidence interval 2.1 to 5.6), while for reference intervals there were no significant changes between editions. In the current edition of the formulary, the 168 secondary sources cited for drug dosages included 78 (46.4%) textbooks, 63 (37.5%) reviews, 14 (8.3%) personal communications and 7 (4.2%) other formularies.

CLINICAL SIGNIFICANCE

A large proportion of references supporting drug dosages and reference intervals in the evaluated sections cited secondary sources. Although modest improvements have been observed over time, practitioners should be aware that the evidence supporting several drugs and dosages was limited, and assess the information within the formulary critically.

Pharmacokinetics and bioavailability of meloxicam in rainbow trout (Oncorhynchus mykiss) broodstock following intravascular, intramuscular, and oral administrations

The pharmacokinetics and bioavailability of meloxicam were investigated after single intravascular (IV), intramuscular (IM), and oral dose of 1 mg/kg in rainbow trout broodstock at 11 ± 1.2°C. A total of 36 healthy rainbow trout (Oncorhynchus mykiss) broodstock weighing 1.40 ± 0.26 kg was used for the investigation. Plasma concentrations of meloxicam were measured with high-performance liquid chromatography-ultraviolet detection, and pharmacokinetic parameters were calculated by non-compartmental analysis. The elimination half-life for IV, IM, and oral routes was 3.63, 4.55, and 2.95 h, respectively. The IV route for meloxicam showed the total clearance of 0.05 L/h/kg and volume of distribution at a steady state of 0.20 L/kg. The peak plasma concentration was 2.97 μg/ml for the IM route and 0.84 μg/ml for the oral route. The bioavailability was 78.45% for the IM route and 21.48% for the oral route. Meloxicam following IM and oral administration displayed short t_1/2ʎz . The short t_1/2ʎz could be an advantage for the short-term use in acute conditions. The IM route with the good bioavailability can be preferred for the treatment of various conditions. However, developing new oral formulations with the good bioavailability for meloxicam is necessary to minimize stress and trauma through minimal handling in rainbow trout broodstock.

Safety and efficacy of cold atmospheric plasma for the sterilization of a Pasteurella multocida-contaminated subcutaneously implanted foreign body in rabbits

OBJECTIVE

To determine whether a stainless steel implant sterilized with a novel cold atmospheric plasma sterilization (CAPS) device adversely affects local tissues in rabbits and whether CAPS was as effective as steam sterilization with an autoclave to inactivate Pasteurella multocida.

ANIMALS

31 healthy New Zealand White rabbits.

PROCEDURES

Steam-autoclaved stainless steel implants inoculated with P multocida underwent a second steam autoclave sterilization (AIA) or CAPS (AICAPS). One AIA implant and 3 AICAPS implants were randomly placed subcutaneously at 4 sites in 21 rabbits (84 implants). These rabbits were monitored daily for 5 days for evidence of systemic illness and local tissue reactions at the implantation sites and then euthanized. Samples were taken from each implant site for bacterial culture and histologic examination.

RESULTS

Cultures of samples obtained from all sites were negative for bacterial growth. No significant difference was observed in mean skin thickness or erythema between AIA and AICAPS implant sites on any observed day. Also, individual histologic grades for the epidermis, dermis, subcutis, and muscle and total histologic grade were not significantly different between AIA and AICAPS implant sites.

CONCLUSIONS AND CLINICAL RELEVANCE

Cold atmospheric plasma sterilization was noninferior to steam sterilization of P multocida-contaminated stainless steel implants in the rabbits in the present study. However, studies of the efficacy of CAPS for inactivation of other important bacteria are needed.

Analgesia in pet rabbits: a survey study on how pain is assessed and ameliorated by veterinary surgeons

BACKGROUND

In the last 20 years, two studies on the veterinary use of perioperative analgesia in small mammals reported a limited use of analgesics in rabbits but suggested an increasing use over the years. The aim of this study was to better understand how pain is treated and ameliorated in rabbits while under veterinary care.

METHODS

An online survey of 60 questions was developed and advertised at national and international veterinary conferences, in veterinary publications and on social media.

RESULTS

In total 94.3 per cent of the respondents routinely administered nonsteroidal anti-inflammatory drugs (NSAIDs) to rabbits undergoing surgical procedures such as neutering, 71.4 per cent administered an opioid and 70.3 per cent routinely administered multimodal analgesia, although dosages do not always match current consensus opinion. Buprenorphine and meloxicam were the most common analgesic drugs prescribed by the respondents. The dosage of meloxicam administered both parenterally and orally varied widely.

CONCLUSION

Rabbit analgesia has improved over recent years similarly to the trend seen in other companion animals. However, overall it seems that pain assessment is still limited in rabbits. The lack of multimodal composite pain scales specific for rabbits makes this task even more challenging.

Pharmacokinetics and absolute oral bioavailability of meloxicam in guinea pigs (Cavia porcellus)

OBJECTIVE

To investigate the pharmacokinetics and absolute oral bioavailability of meloxicam in guinea pigs.

STUDY DESIGN

Prospective crossover study.

ANIMALS

A group of six healthy male Dunkin Hartley guinea pigs.

METHODS

A single dose of meloxicam (1.5 mg kg^-1) was administered orally and intravenously (IV) to six healthy male guinea pigs. A wash-out period of 48 hours was taken into account between administrations (oral and IV) in the same animal. Blood was sampled through a central venous catheter before administration (t = 0 hours) and at 0.5, 1, 2, 3, 4, 6, 8, 10, 12, 16, 20, 24 and 28 hours post administration. After centrifugation, plasma concentrations of meloxicam were measured by high-performance liquid chromatography with UV detection, and pharmacokinetic parameters were calculated using noncompartmental analysis.

RESULTS

Meloxicam in guinea pigs exhibited a moderate absorption rate after oral dosing (time to maximal plasma concentration 3.7 ± 1.7 hours) and maximal plasma concentration was 0.92 ± 0.30 μg mL^-1. After IV administration, total body clearance and volume of distribution were 0.13 ± 0.04 and 0.72 ± 0.36 L kg^-1, respectively. Terminal half-life was 3.7 ± 0.7 hours and 3.5 ± 1.1 hours after IV and oral administration, respectively. Body extraction ratio was 0.0087 and mean absorption time was 3.8 ± 1.7 hours. The absolute oral bioavailability was 0.54 ± 0.14 in unfasted guinea pigs.

CONCLUSIONS AND CLINICAL RELEVANCE

This study reported the pharmacokinetics of meloxicam in guinea pigs. Studies concerning efficacy and safety are the next step towards a rational use of this drug in guinea pigs.

Pharmacokinetics of meloxicam during multiple oral or intramuscular dose administration to African grey parrots (Psittacus erithacus)

OBJECTIVE To determine the pharmacokinetics of meloxicam in African grey parrots (Psittacus erithacus) during administration of multiple doses. ANIMALS 6 healthy African grey parrots. PROCEDURES Meloxicam was administered at each of 3 dosages (1 mg/kg, IM, q 24 h, for 7 days; 1 mg/kg, PO, q 24 h, for 12 days; and 1.6 mg/kg, PO, q 24 h, for 7 days) with an 8-week washout period between treatments. Blood samples were collected 12 and 24 hours after each drug administration (times of presumptive peak and trough drug concentrations) for pharmacokinetic analysis. Birds were visually assessed during all experiments and monitored for changes in selected plasma and urine biochemical variables after administration of the drug at 1.6 mg/kg. RESULTS Mean trough plasma concentrations at steady state were 10.7 and 9.16 μg/mL after meloxicam administration at 1 mg/kg, IM, and 1 mg/kg, PO, respectively. Plasma drug accumulation was evident (accumulation ratios of 2.04 ± 0.30 [IM treatment] and 2.45 ± 0.26 [PO treatment]). Plasma and urine N-acetyl-β-d-glucosaminidase activities were significantly increased at the end of meloxicam treatment at 1.6 mg/kg. CONCLUSIONS AND CLINICAL RELEVANCE Plasma concentrations of meloxicam were maintained at values greater than effective analgesic concentrations described for other avian species. Although administration of meloxicam at a dosage of 1 mg/kg IM and PO daily for 1 week and 12 days, respectively, was not associated with adverse clinical effects in this population, further studies are needed to assess the efficacy and safety of the drug during prolonged treatment and the clinical relevance of its accumulation.

Pain and analgesia in pet rabbits within the veterinary environment: a review

OBJECTIVE

To provide an overview of pain and analgesia in rabbits with the aim of developing a more accurate understanding of these topics. To illustrate and discuss the areas that have advanced in recent years and those that still require further research.

DATABASES USED

Three key subject resources were used: Web of Science, Medline and CAB Abstracts. Search terms were rabbits, lagomorphs, laboratory animals, pet, pain, surgical procedures, ovariohysterectomy, orchiectomy, castration, analgesia, opioids, and non-steroidal anti-inflammatory drugs. References from books and articles relevant to the topics were also included.

CONCLUSIONS

Rabbit medicine has improved over the last 20 years, but the literature suggests that pain management in this species is still inadequate and veterinary professionals believe their knowledge of pain and analgesia in this species is limited. Assessment and quantification of pain in rabbits can be challenging in a clinical environment not only because, as a prey species, rabbits tend to hide signs of pain but also because there are no validated methods to assess pain, except the Rabbit Grimace Scale, which is based on only one rabbit breed. Current consensus is that perioperative multimodal analgesia is the best practice. However, it is not widely used in rabbits. In rabbits, analgesia protocols and dosages reported in the literature are often poorly researched and do not result in complete pain amelioration with the return of normal. The present literature on rabbit pain and analgesia presents gaps either due to unexplored areas or insufficient findings. Further research should focus on these areas with the aim of improving the welfare of rabbits within a veterinary clinic.

Scalable Gastric Resident Systems for Veterinary Application

Gastric resident dosage forms have been used successfully in farm animals for the delivery of a variety of drugs helping address the challenge of extended dosing. Despite these advances, there remains a significant challenge across the range of species with large variation in body size. To address this, we investigate a scalable gastric resident platform capable of prolonged retention. We investigate prototypes in dimensions consistent with administration and retention in the stomachs of two species (rabbit and pig). We investigate sustained gastric retention of our scalable dosage form platform, and in pigs show the capacity to modulate drug release kinetics of a model drug in veterinary practice, meloxicam, with our dosage form. The ability to achieve gastric residence and thereby enable sustained drug levels across different species may have a significant impact in the welfare of animals in both research, agricultural, zoological, and clinical practice settings.

PHARMACOKINETICS OF MELOXICAM FOLLOWING A SINGLE ORAL DOSE IN MALAYAN FLYING FOXES ( PTEROPUS VAMPYRUS)

  Meloxicam, a COX-2 selective nonsteroidal anti-inflammatory medication, has been used in many exotic animals at doses extrapolated from domestic animal pharmacokinetic and pharmacodynamic studies. Increasing evidence suggests that significant species differences exist in meloxicam metabolism. Because of this, dose extrapolation from domestic animals may not be appropriate for exotic species. The objective of this study was to investigate the pharmacokinetics of meloxicam in a population of male Malayan flying foxes, Pteropus vampyrus, following a single oral dose of 0.2 mg/kg. Using a sparse sampling method based on a pilot study, two blood samples from each of 10 bats were collected over an 8-hr time period. Analysis of meloxicam in plasma samples was conducted using reversed-phase high-performance liquid chromatography. The peak plasma concentration of 598 ± 157.5 ng/ml occurred at 1.0 hr post dosing. The terminal half-life was 1.1 ± 0.1 hr, which indicates that meloxicam is rapidly metabolized in this species. No adverse clinical effects were noted during the study period. A single oral dose of 0.2 mg/kg appears safe for use in male Malayan flying foxes, but due to rapid elimination, frequent dosing may be required to maintain plasma concentrations within a therapeutic range. Multidose studies are needed to determine if plasma accumulation of meloxicam occurs.

Cystoscopic diagnosis of polypoid cystitis in two pet rabbits

CASE DESCRIPTION AS-year-old male Dwarf rabbit and 4-year-old female Mini-Rex rabbit were evaluated because of anorexia and urine scalding of the perineum. CLINICAL FINDINGS Abdominal radiography revealed a diffuse increase in the opacity of the urinary bladder attributable to urinary sludge. In 1 rabbit, abdominal ultrasonography revealed several mass-like lesions protruding from the mucosal surface into the lumen of the urinary bladder. Rabbits were anesthetized, and cystoscopy was performed with a rigid 2.7-mm, 30° endoscope. Histologic analysis of tissue samples obtained through the cystoscope operating channel revealed findings consistent with polypoid cystitis. TREATMENT AND OUTCOME To remove the urinary sludge from each rabbit, the urinary bladder was filled with sterile saline (0.9% NaCl) solution and emptied with a gentle massage several times until the ejected fluid was transparent. Rabbits were treated with NSAIDs, antimicrobials (chosen following microbial culture of urine and antimicrobial susceptibility testing), bathing of the perineum, and a low-calcium diet. The male rabbit died of unrelated causes 18 months later; postmortem examination findings confirmed the polypoid cystitis. The female rabbit remained disease free through to last follow-up (12 months after initial evaluation). CLINICAL RELEVANCE This was the first report of polypoid cystitis in pet rabbits. Although ultrasonographic findings supported this diagnosis, a definitive diagnosis was achieved through cystoscopy and lesion biopsy. Treatments administered were intended to reduce the potential sources of irritation. Research is needed to investigate the effectiveness of the applied interventions and the association between excessive urinary calcium excretion and polyploid cystitis in rabbits.

Advancements in Evidence-Based Analgesia in Exotic Animals

The importance of appropriate recognition, assessment, and treatment of pain in all veterinary species, including exotic animals, cannot be overstated. Although the assessment of pain perception in nondomestic species is still in its infancy, this does not preclude appropriate analgesic management in these species. Although analgesic drug selection is often based on data extrapolated from similar species, as the pharmacokinetics and pharmacodynamics of many drugs can vary greatly between species, an evidence-based approach to analgesic therapy should be used whenever possible. This article provides an overview of recent advances in evidence-based analgesic management in companion exotic animals.

PHARMACOKINETIC EVALUATION OF MELOXICAM AFTER INTRAVENOUS AND INTRAMUSCULAR ADMINISTRATION IN NILE TILAPIA (OREOCHROMIS NILOTICUS)

Critically evaluating the pharmacokinetic behavior of a drug in the body provides crucial information about how to effectively treat a patient. Pharmacokinetic studies that exist in fish have primarily focused on drugs used to treat infectious disease, with minimal attention given to analgesic drugs. The objective of this study was to determine the pharmacokinetics of meloxicam (1 mg/kg) in Nile tilapia ( Oreochromis niloticus ) (n = 12). A single dose of meloxicam was administered either i.v. or i.m. Blood samples were obtained at predetermined times after drug injection. Plasma meloxicam concentrations were determined by a validated liquid chromatography/mass spectrometry method, and noncompartmental pharmacokinetic analysis was performed. The mean peak plasma concentration after i.m. injection was 1.95 μg/ml. The mean terminal half-life of meloxicam after i.v. and i.m. administration was 1.36 and 1.8 hr, respectively. The area under the plasma concentration-versus-time curve extrapolated to infinity was 11.26 hr·μg/ml after i.v. administration and 5.72 hr·μg/ml after i.m. administration. Bioavailability of meloxicam after i.m. administration was approximately half that of i.v. administration. Elimination was rapid in both the i.m. and i.v. routes of administration, suggesting that maintaining clinically relevant plasma concentrations may be difficult using this dose. This study represents the first pharmacokinetic evaluation of a nonsteroidal anti-inflammatory drug in a fish species, and further studies evaluating efficacy are needed.

Advances in exotic mammal clinical therapeutics

It is important that veterinarians treating exotic companion mammals stay abreast of the latest developments relating to medications and drug delivery approaches for safety, efficacy and welfare issues. Sustained release formulations of commonly used drugs as well as newer routes for administration of therapeutic agents allow the veterinarian treating exotic companion mammals to reduce the stress associated with drug administration. Interactions can occur between vehicle and drugs when formulations are compounded, therefore research studies are warranted regarding potential problems associated with these formulations.

Molecular analysis of the microbiota in hard feces from healthy rabbits (Oryctolagus cuniculus) medicated with long term oral meloxicam

Background

Analgesia is often indicated in rabbits undergoing surgical procedures or suffering from various painful conditions and the most common adverse effects associated with NSAIDs occur in the gastrointestinal tract (GIT). The objective of this study was to determine the potential effect of long-term (21 days) meloxicam administration on the fecal bacterial microbiota in healthy rabbits.

Samples of hard feces were collected from six rabbits treated with meloxicam (1 mg/kg orally once every 24 h) on days 0,6,14 and 21. Next generation sequencing of V4 16S rRNA gene products was performed.

Results

A total of 2589912 V4 rRNA gene sequences passed all quality control filters. Firmicutes predominated (82.0 ± 6.2%). Sixteen other phyla were also identified but other than Verrucomicrobia (4.4 ± 4.9%), all accounted for less than 1% of the identified sequences. Within Firmicutes, Clostridia was the dominant class, accounting for 76% of operational taxon units (OTUs). In general, there were only few differences observed between time points and different rabbits at the phylum level. A significant change was observed in the relative abundance of Proteobacteria over the 4 time points (P = 0.02).

Conclusions

The gastrointestinal tract of rabbits harbors dense and diverse microbiota. Significant alteration of the hard fecal microbiota does not appear to be a considerable adverse effect expected in rabbits treated for 21 days with oral meloxicam at a dose of 1 mg/kg.