Effects of meloxicam on renal function in dogs with hypotension during anaesthesia

Twelve previously healthy non-geriatric dogs present for acute kidney injury after general anaesthesia for non-emergency surgical procedures in the UK

OBJECTIVES

To characterise common factors after a suspected increase in the incidence of post-procedure acute kidney injury in healthy dogs presenting for non-emergency surgical procedures.

MATERIALS AND METHODS

Retrospective analysis of the medical records of 12 dogs that presented for acute kidney injury after general anaesthesia for non-emergency surgical procedures.

RESULTS

The 12 non-geriatric dogs re-presented with acute kidney injury at a median of 4 days after surgery to four different veterinary centres, including three multidisciplinary referral practices in the UK. All dogs in this case series weighed more than 20 kg and had a median age of 17 months. There was no apparent association with breed, type of surgery, duration of anaesthesia, perioperative drug choice or non-steroidal anti-inflammatory drug administration.

CLINICAL SIGNIFICANCE

Although well-defined in human medicine, there is very little information regarding the association between general anaesthesia and acute kidney injury in animals. No definitive causal link was found in this case series. Clinicians with similar cases are requested to contact the corresponding author so a more representative incidence rate can be obtained.

Antiinflammatory Drugs

This article reviews the mechanisms of action, clinical use, and recent scientific evidence for the use of nonsteroidal antiinflammatory drugs, grapiprant, acetaminophen (paracetamol), metamizole (dipyrone), and corticosteroids in pain management. The discussion is presented with an emphasis on the treatment of acute pain.

Hypoxia alters the thermogenic response to cold in adult homeothermic and heterothermic rodents

KEY POINTS

For small mammals living in a cold, hypoxic environment, supplying enough O₂ to sustain thermogenesis can be challenging. While heterothermic mammals are generally more tolerant of cold and hypoxia than homeothermic mammals, how they regulate O₂ supply and demand during progressive cooling in hypoxia is largely unknown. We show that as ambient temperature is reduced in hypoxia, body temperature falls in both homeotherms and heterotherms. In the homeothermic rat, a decrease in O₂ consumption rate and lung O₂ extraction accompany this fall in body temperature, despite a relative hyperventilation. Paradoxically, in heterothermic mice, hamsters and ground squirrels, body temperature decreases more than in the homeothermic rat, even though they maintain ventilation, increase lung O₂ extraction and maintain or elevate their O₂ consumption rates. Variation in cold and hypoxia tolerance among homeotherms and heterotherms reflects divergent strategies in how O₂ supply and demand are regulated under thermal and hypoxic challenges.

ABSTRACT

Compared to homeothermic mammals, heterothermic mammals are reported to be exceptionally tolerant of cold and hypoxia. We hypothesised that this variation in tolerance stems from divergent strategies in how homeotherms and heterotherms regulate O₂ supply versus O₂ demand when exposed to hypoxia during progressive cooling. To test this hypothesis, we exposed adult rodents ranging in their degree of heterothermic expression (homeotherm: rats, facultative heterotherms: mice and hamsters, and obligate heterotherm: ground squirrels) to either normoxia (21% O₂ ) or environmental hypoxia (7% O₂ ), while reducing ambient temperature from 38 to 5°C. We found that when ambient temperature was reduced in normoxia, all species increased their O₂ consumption rate and ventilation in parallel, maintaining a constant ventilatory equivalent and level of lung O₂ extraction. Surprisingly, body temperature fell in all species, significantly so in the heterotherms. When ambient temperature was reduced in hypoxia, however, the homeothermic rat decreased their O₂ consumption rate and lung O₂ extraction despite an increase in their ventilatory equivalent, indicative of a relative hyperventilation. Heterotherms (mice, hamsters and ground squirrels), on the other hand, decreased their ventilatory equivalent, but increased lung O₂ extraction and maintained or elevated their O₂ consumption rates, yet their body temperature fell even more than in the rat. These results are consistent with the idea that homeotherms and heterotherms diverge in the strategies they use to match O₂ supply and O₂ demand, and that enhanced cold and hypoxia tolerance in heterotherms may stem from an improved ability to extract O₂ from the inspired air.

Effect of benazepril and robenacoxib and their combination on glomerular filtration rate in dogs

Combined use of angiotensin-converting enzyme inhibitors and nonsteroidal anti-inflammatory drugs may induce acute kidney injury, especially when combined with diuretics. The objective of this investigation was to evaluate the effect of benazepril, robenacoxib and their combination in healthy dogs. In each of two studies (studies 1 and 2), 32 beagle dogs were randomized into one of four groups in a parallel-group design. Groups received once-daily oral treatment for 7 days with placebo, benazepril, robenacoxib or benazepril plus robenacoxib. In study 2, all dogs received additionally 2 mg/kg furosemide orally twice daily. The primary endpoint was the glomerular filtration rate (GFR) estimated from the plasma clearance of iohexol. Secondary endpoints included standard clinical monitoring and, in study 2, plasma renin activity, urine volume, specific gravity and aldosterone concentration and water intake. Administration of furosemide induced diuresis, reduced GFR and activated the renin-aldosterone-angiotensin system. Benazepril and robenacoxib, administered alone or in combination, were tolerated well, did not decrease GFR with or without co-administration of furosemide and significantly reduced urinary aldosterone concentrations. No increased risk of acute kidney injury was identified with the combination of benazepril and robenacoxib in healthy dogs. Different effects might occur in dogs with heart or renal disease.

An analysis of the relative frequencies of reported adverse events associated with NSAID administration in dogs and cats in the United Kingdom

This study aimed to analyse UK pharmacovigilance data to quantify adverse events (AEs) associated with the non-steroidal anti-inflammatory drug (NSAID) molecules found in veterinary medicines authorised for use in dogs and cats. It was hypothesised that the frequency of AEs would be lower when associated with cyclo-oxygenase-2 selective (coxib), compared to non-selective (non-coxib) NSAIDs. The UK Veterinary Medicines Directorate (VMD) supplied frequencies of AEs derived from Periodic Safety Update Reports subdivided by formulation and species for each NSAID molecule. Frequencies of AEs were similar between species. The five most reported AEs were emesis, death, anorexia, lethargy, and diarrhoea. Reported frequency of emesis, renal insufficiency and death was higher with injectable compared to oral NSAIDs (P = 0.043). Reported frequency of emesis, lethargy and death was higher with coxib, compared to non-coxib NSAIDs (P = 0.029). Median (range) interval since authorisation was shorter for coxibs at 5 (2.5-9) years compared to non-coxibs at 15 (12-25) years. A negative correlation between time elapsed since authorisation and the frequency of AEs was identified (rs = -0.11 to -0.94). Higher frequency of reported AEs with injectable NSAIDs may be related to perioperative administration. The AE frequency associated with coxib and non-coxib NSAIDs may be confounded by changes in reporting habits over time. This study highlights the value of interrogating passive surveillance data to identify low frequency AEs and the need to facilitate improvement in recording and collecting AEs in small animal practice.

Systematic review of nonsteroidal anti-inflammatory drug-induced adverse effects in dogs

The aim of this systematic review was to identify, assess, and critically evaluate the quality of evidence of nonsteroidal anti-inflammatory drug (NSAID)-induced adverse effects in dogs. Original prospective studies published in peer-reviewed journals in English (1990-2012) that reported data on the safety of NSAIDs administration in dogs were searched. For each study, design type (I, II, III, or IV) and assessment of quality (+, Ø, -) were rated. For each drug, quantity and consistency rating (***, **, *) and strength of evidence (high, moderate, low, or extremely low) were identified and evaluated. The strength of evidence was defined in terms of how applicable and relevant the conclusions were to the target population. Sixty-four studies met the inclusion criteria. Thirty-five (55%) research studies and 29 (45%) clinical trials were identified. A high strength of evidence existed for carprofen, firocoxib, and meloxicam; moderate for deracoxib, ketoprofen, and robenacoxib; and low for etodolac. Quality and consistency rating were as follows: carprofen (***/***), deracoxib (**/***), etodolac (*/unable to rate), firocoxib (***/**), ketoprofen (**/***), meloxicam (***/***), and robenacoxib (**/**), respectively. Adverse effects were detected in 35 studies (55%) and commonly included vomiting, diarrhea, and anorexia. Three studies (5%) reported a power analysis related to adverse effects of ≥80%. In randomized, placebo-controlled, blinded studies (n = 25, 39%), the incidence of adverse effects was not statistically different between treated and control dogs. Finally, most studies were not appropriately designed to determine the safety of NSAIDs, and involved a healthy nongeriatric population of research dogs.

Effects of meloxicam on hematologic and plasma biochemical analysis variables and results of histologic examination of tissue specimens of Japanese quail (Coturnix japonica)

OBJECTIVE

To determine the effects of meloxicam on values of hematologic and plasma biochemical analysis variables and results of histologic examination of tissue specimens of Japanese quail (Coturnix japonica).

ANIMALS

30 adult Japanese quail.

PROCEDURES

15 quail underwent laparoscopic examination of the left kidneys, and 15 quail underwent laparoscopic examination and biopsy of the left kidneys. Quail in each of these groups received meloxicam (2.0 mg/kg, IM, q 12 h; n = 10) or a saline (0.9% NaCl) solution (0.05 mL, IM, q 12 h; control birds; 5) for 14 days. A CBC and plasma biochemical analyses were performed at the start of the study and within 3 hours after the last treatment. Birds were euthanized and necropsies were performed.

RESULTS

No adverse effects of treatments were observed, and no significant changes in values of hematologic variables were detected during the study. Plasma uric acid concentrations and creatine kinase or aspartate aminotransferase activities were significantly different before versus after treatment for some groups of birds. Gross lesions identified during necropsy included lesions at renal biopsy sites and adjacent air sacs (attributed to the biopsy procedure) and pectoral muscle hemorrhage and discoloration (at sites of injection). Substantial histopathologic lesions were limited to pectoral muscle necrosis, and severity was greater for meloxicam-treated versus control birds.

CONCLUSIONS AND CLINICAL RELEVANCE

Meloxicam (2.0 mg/kg, IM, q 12 h for 14 days) did not cause substantial alterations in function of or histopathologic findings for the kidneys of Japanese quail but did induce muscle necrosis; repeated IM administration of meloxicam to quail may be contraindicated.

Evaluation of subcutaneous and oral administration of robenacoxib and meloxicam for the treatment of acute pain and inflammation associated with orthopedic surgery in dogs

OBJECTIVE

To assess efficacy and tolerability of robenacoxib for control of pain and inflammation in dogs undergoing orthopedic surgery.

ANIMALS

140 client-owned dogs.

PROCEDURES

A multicenter, prospective, randomized, blinded field trial was conducted to compare robenacoxib (97 dogs) and meloxicam (43 dogs). After randomization, each dog received an initial dose (robenacoxib, 2 mg/kg; meloxicam, 0.2 mg/kg) via SC injection before surgery and daily doses (robenacoxib, 1 to 2 mg/kg; meloxicam, 0.1 mg/kg) administered orally for up to 15 days after surgery. Efficacy was assessed by veterinarians and owners via numeric rating scales and visual analogue scales. Safety was assessed on the basis of reported adverse events, clinical signs, results of hematologic and biochemical analyses, and buccal mucosa bleeding times.

RESULTS

Treatment groups were balanced with respect to baseline and demographic data. Both treatments provided similar adequate pain control, as assessed with a modified Glasgow pain scale as the primary end point and supported by secondary end points in evaluations conducted by veterinarians and owners. For the primary end point, the ratio of the reciprocal of the scores for robenacoxib to meloxicam was 1.16 (95% confidence interval, 0.98 to 1.37). No dogs required rescue analgesia. Both treatments were associated with only minor adverse events, which were not necessarily related to the administered treatments and did not affect mucosal bleeding times.

CONCLUSIONS AND CLINICAL RELEVANCE

Robenacoxib provided efficacy and tolerability similar to those of meloxicam for the management of perioperative pain and inflammation in dogs undergoing orthopedic surgery.

Perioperative administration of vedaprofen, tramadol or their combination does not interfere with platelet aggregation, bleeding time and biochemical variables in cats

A randomized double blind and placebo controlled design was used to investigate the hemostatic, biochemical, gastrointestinal and behavioral effects of pre- and postoperative administration of vedaprofen 0.5mg/kg PO (V), tramadol 2mg/kg SC (T), their association (VT) or placebo (P) in 40 adult female cats (3.0+/-0.32kg; 1.8+/-0.7 years) distributed in groups of 10. Platelet aggregation and bleeding time were measured before and 52h after ovariohysterectomy. Serum urea, creatinine, alanine aminotransferase, alkaline phosphatase and gamma-glutamyl transferase concentrations were measured before and 7 days postoperatively. The occurrence of vomiting, frequency and consistency of feces, and behavior were observed for 7 days postoperatively. Morphine (0.5mg/kg, IM) was used as rescue analgesic. Laboratory variables did not change. Vomiting was observed only after morphine administration. Mild euphoria was observed in T and VT. The perioperative use of vedaprofen and/or tramadol did not modify the hemostatic, biochemical and gastrointestinal function in cats.

Renal effect of meloxicam versus ketoprofen in anaesthetized pseudo-normovolaemic piglets

Due to renal COX-2 constitutive expression, meloxicam is presumably deleterious for kidney function in critical situations. The present study investigates the influence of intravenous meloxicam on renal parameters and compares it with a nonselective COX inhibitor, ketoprofen. Piglets (n = 6 in each group) were treated with ketoprofen (2 mg·kg–1), meloxicam (0.2 mg·kg–1), or saline at the beginning of anaesthesia. Under intravenous anaesthesia, pigs were instrumented for cardiovascular, respiratory, and renal function evaluation, including urinary flow (UF), glomerular filtration rate (GFR), and renal blood flow (RBF). After baseline data collection (U0), data collection consisted of six 20-minute periods (U1 to U6). In all groups, the time course of cardiovascular and respiratory parameters remained within normal ranges. A small decrease in cardiac output and an increase in mean systemic arterial blood pressure (p = 0.002) occurred in all groups. In the placebo group, a similar decrease was observed for RBF and cardiac output, with troughs of –10.1% ± 6.8%, and –12.9% ± 3.2%, respectively. GFR and UF, however, remained stable over time in this group. Ketoprofen significantly decreased UF (–29.3% ± 5.5% max at U3), with similar decreases in GFR and RBF. Meloxicam induced a transient (at U2) and small decrease in UF with no difference, at any time point, with the placebo group. The renal effects of meloxicam appear minimal and transient in anaesthetized piglets. This study demonstrates the safety of meloxicam for preemptive surgical analgesia under conditions of normovolaemia. Fluid therapy appears recommended to prevent any renal dysfunction.

Evaluation of adverse effects of long-term oral administration of carprofen, etodolac, flunixin meglumine, ketoprofen, and meloxicam in dogs

OBJECTIVE

To evaluate adverse effects of long-term oral administration of carprofen, etodolac, flunixin meglumine, ketoprofen, and meloxicam in dogs.

ANIMALS

36 adult dogs.

PROCEDURES

Values for CBC, urinalysis, serum biochemical urinalyses, and occult blood in feces were investigated before and 7, 30, 60, and 90 days after daily oral administration (n = 6 dogs/group) of lactose (1 mg/kg, control treatment), etodolac (15 mg/kg), meloxicam (0.1 mg/kg), carprofen (4 mg/kg), and ketoprofen (2 mg/kg for 4 days, followed by 1 mg/kg daily thereafter) or flunixin (1 mg/kg for 3 days, with 4-day intervals). Gastroscopy was performed before and after the end of treatment.

RESULTS

For serum gamma-glutamyltransferase activity, values were significantly increased at day 30 in dogs treated with lactose, etodolac, and meloxicam within groups. Bleeding time was significantly increased in dogs treated with carprofen at 30 and 90 days, compared with baseline. At 7 days, bleeding time was significantly longer in dogs treated with meloxicam, ketoprofen, and flunixin, compared with control dogs. Clotting time increased significantly in all groups except those treated with etodolac. At day 90, clotting time was significantly shorter in flunixin-treated dogs, compared with lactose-treated dogs. Gastric lesions were detected in all dogs treated with etodolac, ketoprofen, and flunixin, and 1 of 6 treated with carprofen.

CONCLUSIONS AND CLINICAL RELEVANCE

Carprofen induced the lowest frequency of gastrointestinal adverse effects, followed by meloxicam. Monitoring for adverse effects should be considered when nonsteroidal anti-inflammatory drugs are used to treat dogs with chronic pain.

Action of diclofenac on kidney mitochondria and cells

The mitochondrial membrane potential measured in isolated rat kidney mitochondria and in digitonin-permeabilized MDCK type II cells pre-energized with succinate, glutamate, and/or malate was reduced by micromolar diclofenac dose-dependently. However, ATP biosynthesis from glutamate/malate was significantly more compromised compared to that from succinate. Inhibition of the malate-aspartate shuttle by diclofenac with a resultant decrease in the ability of mitochondria to generate NAD(P)H was demonstrated. Diclofenac however had no effect on the activities of NADH dehydrogenase, glutamate dehydrogenase, and malate dehydrogenase. In conclusion, decreased NAD(P)H production due to an inhibition of the entry of malate and glutamate via the malate-aspartate shuttle explained the more pronounced decreased rate of ATP biosynthesis from glutamate and malate by diclofenac. This drug, therefore affects the bioavailability of two major respiratory complex I substrates which would normally contribute substantially to supplying the reducing equivalents for mitochondrial electron transport for generation of ATP in the renal cell.