Effects of long-term use of the preferential COX-2 inhibitor meloxicam on growing pigs.

Meloxicam, a preferential COX-2 inhibitor, is a commonly used NSAID in pigs. Besides having potential side effects on the gastrointestinal tract, this type of drug might potentially affect osteogenesis and chondrogenesis, processes relevant to growing pigs. Therefore, the effects of long-term meloxicam treatment on growing pigs were studied. Twelve piglets (n=6 receiving daily meloxicam 0.4 mg/kg orally from 48 until 110 days of age; n=6 receiving only applesauce (vehicle control)) were subjected to visual and objective gait analysis by pressure plate measurements at several time points. Following euthanasia a complete postmortem examination was performed and samples of the talus and distal tibia, including the distal physis, were collected. Trabecular bone microarchitecture was analysed by microCT scanning, bone stiffness by compression testing and growth plate morphology using light microscopy. Animals were not lame and gait patterns did not differ between the groups. Pathological examination revealed no lesions compatible with known side effects of NSAIDs. Trabecular bone microarchitecture and growth plate morphology did not differ between the two groups. The findings of this in vivo study reduce concerns regarding the long-term use of meloxicam in young, growing piglets.

Comparison of three different sedative-anaesthetic protocols (ketamine, ketamine-medetomidine and alphaxalone) in common marmosets (Callithrix jacchus).

BACKGROUND: Handling of common marmoset (Callithrix jacchus) usually requires chemical restraint. Ketamine has been associated with muscle damage in primates, while common marmosets, compared to other primates, additionally display an exceptional high sensitivity to ketamine-associated side-effects. Notably, muscle twitching movements of limbs and hands, and a marked increase in salivation are observed. We investigated two alternative intramuscular (i.m.) immobilisation protocols against ketamine (50 mg/kg; protocol 1) in a double-blind randomised crossover study in ten healthy adult common marmosets for use as a safe reliable, short-term immobilisation and sedation. These protocols comprised: alphaxalone (12 mg/kg; protocol 2) and 25 mg/kg ketamine combined with 0.50 mg/kg medetomidine (reversal with 2.5 mg/kg atipamezole; protocol 3A). Following completion and unblinding, the project was extended with an additional protocol (3B), comprising 25 mg/kg ketamine combined with 0.05 mg/kg medetomidine (reversal with 0.25 mg/kg atipamezole, twice with 35 min interval). RESULTS: All protocols in this study provided rapid onset (induction times <5 min) of immobilisation and sedation. Duration of immobilisation was 31.23 ± 22.39 min, 53.72 ± 13.08 min, 19.73 ± 5.74 min, and 22.78 ± 22.37 min for protocol 1, 2, 3A, and 3B, respectively. Recovery times were 135.84 ± 39.19 min, 55.79 ± 11.02 min, 405.46 ± 29.81 min, and 291.91 ± 80.34 min, respectively. Regarding the quality, and reliability (judged by pedal withdrawal reflex, palpebral reflex and muscle tension) of all protocols, protocol 2 was the most optimal. Monitored vital parameters were within clinically acceptable limits during all protocols and there were no fatalities. Indication of muscle damage as assessed by AST, LDH and CK values was most prominent elevated in protocol 1, 3A, and 3B. CONCLUSIONS: We conclude that intramuscular administration of 12 mg/kg alphaxalone to common marmosets is preferred over other protocols studied. Protocol 2 resulted in at least comparable immobilisation quality with acceptable and less frequent side effects and superior recovery quality. In all protocols, supportive therapy, such as external heat support, remains mandatory. Notably, an unacceptable long recovery period in both ketamine/medetomidine protocols (subsequently reversed with atipamezole) was observed, showing that α-2 adrenoreceptor agonists in the used dose and dosing regime is not the first choice for sedation in common marmosets in a standard research setting.

Optimizing the dosing interval of buprenorphine in a multimodal postoperative analgesic strategy in the rat: minimizing side-effects without affecting weight gain and food intake.

Buprenorphine is commonly used as (part of) postoperative analgesic treatment with dosage dependent side-effects such as pica behaviour. No strict consensus exists about the optimal dosing interval of buprenorphine, as its duration of action has been described as being in the range of 6-12 h. In this study, dosing intervals of 8 h (thrice-a-day) and 12 h (twice-a-day) for buprenorphine in a multimodal analgesic strategy (concurrent administration of a non-steroidal anti-inflammatory drug) were compared on food intake, weight and side-effects (gnawing on plastic Petri dishes and growth rate, indicative of pica behaviour) in rats. The food intake and weight of both intervals were comparable, as the animals from the twice-a-day group did not lose more weight or consumed less food during the analgesic period. The rats from the thrice-a-day group suffered from more side-effects, as the growth rate was decreased and more plastic was gnawed on. It is recommended to carefully evaluate analgesic and side-effects when using buprenorphine. When side-effects are observed, the possibility of increasing the dosing interval of buprenorphine should be explored. In this study, increasing the dosing interval of buprenorphine in a multimodal analgesic regimen resulted in reduced unwanted side-effects, without increasing weight loss or decreasing food intake. Although this is suggestive of provision of comparable analgesia, future studies including more pain-related readout parameters to assess the effect of the dosing interval on analgesic efficacy are recommended.

Ultrasound-guided serial transabdominal cardiac biopsies in cats.

A percutaneous/transdiaphragmatic core needle biopsy technique was developed in cats to obtain serial biopsies from different locations of the left ventricle, through which morphological and molecular changes within the same individual can be studied to unravel the mechanisms of feline cardiomyopathies. Transmural left ventricular myocardial samples were obtained from 29 anesthetized, healthy, adult cats with ultrasound guidance. An 18G automatic biopsy needle was inserted between the last left rib and the sternum through the diaphragm into the thorax. Biopsies were obtained from the left ventricular wall. In five cats, three single biopsies were taken with 4-week intervals. Autopsy was performed on six cats, of which three cats had serial biopsies. In total, 87 biopsies were obtained without long-term effects on cardiac function or structure. The biopsies caused transient single ventricular premature complexes and mild pericardial effusion without tamponade. Necropsy revealed a minimal amount of fibrous connective tissue in the diaphragm and the heart without any significant microscopic lesions in the adjacent muscle tissue. The high quality biopsy material was suitable for morphological and molecular studies. This minimally invasive, ultrasound-guided cardiac biopsy technique thus allows for the safe collection of serial biopsies to study feline cardiomyopathies in an experimental setting.

Pain management in ferrets.

The growing popularity of ferrets as pets has created the demand for advanced veterinary care for these patients. Pain is associated with a broad range of conditions, including acute or chronic inflammatory disease, neoplasia, and trauma, as well as iatrogenic causes, such as surgery and diagnostic procedures. Effective pain management requires knowledge and skills to assess pain, good understanding of the pathophysiology of pain, and general knowledge of pharmacologic and pharmacodynamic principles. Unfortunately, scientific studies on efficacy, pharmacokinetics, pharmacodynamics, and safety of analgesic drugs in the ferret are limited. However, basic rules on the treatment of pain and mechanisms of action, safety, and efficacy of analgesic drugs in other species can be adapted and applied to pain management in ferrets. This article aims to make an inventory of what is known on the recognition of pain in ferrets, what analgesic drugs are currently used in ferrets, and how they can be adopted in a patient-orientated pain management plan to provide effective pain relief while reducing and monitoring for unwanted side effects.

Dexmedetomidine continuous rate infusion during isoflurane anaesthesia in canine surgical patients.

OBJECTIVE: To determine the effects of three rates of dexmedetomidine (DMED) constant rate infusion (CRI) on overall tissue perfusion, isoflurane (ISO) requirements, haemodynamics and quality of recovery in canine surgical patients. STUDY DESIGN: Prospective, randomized, blinded clinical study. ANIMALS: Client-owned dogs presented for soft tissue or orthopaedic surgery. METHODS: Following intravenous (IV) pre-medication with DMED (5 microg kg(-1)) and buprenorphine (10 microg kg(-1)) and propofol induction, anaesthesia was maintained with ISO in oxygen/air supplemented with a DMED CRI (1, 2 or 3 microg kg(-1) hour(-1); groups 1, 2 and 3, respectively). Ventilation was controlled in all animals using intermittent positive pressure ventilation (IPPV). Monitoring included end-tidal (ET) gases, ECG, arterial blood pressure, body temperature and sequential arterial blood gas and lactate measurements. Quality of recovery was scored after intramuscular (IM) administration of atipamezole (ATI) (12.5 microg kg(-1)). Immediate post-operative analgesia was provided with carprofen and/or buprenorphine. An analysis of variance was conducted for repeated measurements obtained during 80 minutes after first incision. Categorical data were evaluated with Chi-square analyses. RESULTS: Arterial blood pressure remained stable and within clinically acceptable limits. Mean heart rate in group 2 was significantly lower than in group 1. The incidence of 2nd degree AV block type II was significantly higher in group 3. Mean arterial lactate concentrations remained below 2 mmol/L in all groups during the study, with a significant increase occurring during recovery compared with surgery for group 3. Mean e'ISO% was similar and <1% in all groups. Complete recovery from anaesthesia was achieved after ATI administration and was of good quality in all but three animals. CONCLUSIONS AND CLINICAL RELEVANCE: Dexmedetomidine CRI is a reliable and valuable adjunct to ISO anaesthesia in maintaining surgical anaesthesia in ASA I-II dogs. Data reported indicate adequate overall tissue perfusion and a low ISO requirement while enabling a smooth and rapid recovery following ATI. The DMED CRI of 1 microg kg(-1) hour(-1) following a loading dose of 5 microg kg(-1) produced the most favourable results.