Nonsteroidal anti-inflammatory drugs and corticosteroids for the management of canine osteoarthritis

The clinical, cerebrospinal fluid, and histopathologic effects of epidural ketorolac in dogs

OBJECTIVE

To evaluate the clinical, cerebrospinal fluid (CSF), and histopathologic effects of epidural ketorolac.

STUDY DESIGN

Blinded, randomized, placebo controlled study.

ANIMALS

Twenty-two adult mixed breed dogs with 16 treatment and 6 control dogs, weighing 14.4 to 29.8 kg.

METHODS

Dogs were anesthetized and epidural catheters were placed at the lumbosacral space. Catheter placement was evaluated fluoroscopically. Ketorolac (0.4 mg/kg) or placebo (5% ethanol) was administered epidurally over a 52-hour period, with 5 injections given at 12-hour intervals. At 1, 2, 4, or 8 hours after the first and last injection of ketorolac, dogs were anesthetized and CSF was obtained. Control dogs had CSF sampled 1 hour after the first and last ethanol injection. Neurologic function and pain responses were evaluated before and during the study. Selected dogs were then killed and necropsies performed.

RESULTS

None of the dogs exhibited any clinical or neurologic abnormalities during the study. No statistical difference was noted in pain response or CSF analysis between treatment and control dogs. Gross necropsy revealed gastrointestinal ulceration of varying degrees in all treatment dogs. Histopathologic analysis of the spinal cord and meninges revealed minimal focal leptomeningeal phlebitis in 2 of 8 treatment dogs and minor subdural inflammation in 1 control dog. No changes to the neural structures were noted in any dogs.

CONCLUSIONS

Epidural administration of ketorolac did not cause clinical signs, alteration in CSF values, or pathologic changes to the spinal cord when used for short duration. Gastrointestinal ulceration was common when ketorolac was administered epidurally at 0.4 mg/kg every 12 hours for 5 treatments.

CLINICAL RELEVANCE

This study documented the neurologic safety of epidural ketorolac in dogs before an efficacy trial can be performed. Gastrointestinal ulceration may limit use to short duration or a single injection.

Pharmacologic considerations for opiate analgesic and nonsteroidal anti-inflammatory drugs

When administering opioid analgesic drugs or nonsteroidal anti-inflammatory drugs, veterinarians are often not familiar enough with the underlying pharmacology of the drugs, particularly with the potential for drug interactions and adverse effects. This article considers some of the pharmacologic features of these drugs and provides a basis for important interactions, contraindications, and adverse effects.

Management of chronic osteoarthritic pain

Osteoarthritis is a common cause of chronic pain in small animals. Although there is currently no known cure, the disease can often be palliated by a combination of weight control, regulated exercise, anti-inflammatory medications, and disease-modifying osteoarthritic agents. The diagnosis, recommended treatments, and many of the newer drugs and disease-modifying agents are discussed in this article.

Self-selection of the analgesic drug carprofen by lame broiler chickens

Lame and sound broilers, selected from commercial flocks, were trained to discriminate between different coloured feeds, one of which contained carprofen. The two feeds were then offered simultaneously and the birds were allowed to select their own diet from the two feeds. In an initial study to assess the most appropriate concentration of drug, the plasma concentrations of carprofen were linearly related to the birds' dietary intake. The walking ability of lame birds was also significantly improved in a dose-dependent manner and lame birds tended to consume more analgesic than sound birds. In a second study, in which only one concentration of analgesic was used, lame birds selected significantly more drugged feed than sound birds, and that as the severity of the lameness increased, lame birds consumed a significantly higher proportion of the drugged feed.

Apocynin, a plant-derived, cartilage-saving drug, might be useful in the treatment of rheumatoid arthritis

OBJECTIVE

To investigate whether apocynin, 1-(4-hydroxy-3-methoxyphenyl)ethanone, is able to diminish inflammation-induced cartilage destruction in rheumatoid arthritis (RA), studied in a human in vitro model.

METHODS

Apocynin was added to cultures of RA peripheral blood mononuclear cells (PBMNC). Cartilage-destructive activity was determined by addition of culture supernatant to tissue samples of human articular cartilage. In addition, the proliferation of PBMNC, their production of tumour necrosis factor alpha (TN-Falpha), interleukin (IL)-1 and IL-10, and T-cell production of interferon gamma (IFN-gamma) and IL-4, as measures for T1 and T2 cell activity, were determined.

RESULTS

Apocynin was able to counteract RA PBMNC-induced inhibition of cartilage matrix proteoglycan synthesis, while no effect on inflammation-enhanced proteoglycan release was found. The effect was accompanied by a decrease in IL-1 and TNF-alpha production by the MNC. No effect on T-cell proliferation was found, but the production of IFN-gamma, IL-4 and T-cell-derived IL-10 was strongly diminished. Most important, apocynin did not show any direct adverse effects on chondrocyte metabolism; on the contrary, it diminished the release of proteoglycans from the cartilage matrix.

CONCLUSION

Apocynin in vitro inhibits inflammation-mediated cartilage destruction without having adverse effects on cartilage. The latter may be an advantage of apocynin over many other non-steroidal anti-inflammatory drugs. Therefore, apocynin might have an added beneficial effect in protecting RA patients from joint destruction.

Recent information about hip dysplasia

Dogs suffering from HD have a genetic background, but the releasing factors are many. Two of the most important are overnutrition and overexercising, especially in the young puppy. Radiography can give an estimate of the degree of secondary OA, and by evaluating the laxity in the hip joints at an early age, it seems to be possible to predict the chances for later development of OA. The eradication program has to be instituted in such a way that only the best dogs are accepted into breeding programs. It seems to be more efficient to eradicate the genetic part of the etiology by creating a breeding index by means of evaluating the offspring of the male dogs.

Effects of the NSAIDs meloxicam and indomethacin on cartilage proteoglycan synthesis and joint responses to calcium pyrophosphate crystals in dogs

NSAIDs are a major cause for concern for their propensity to cause joint deterioration in canine, as in human, patients receiving these drugs for treatment of pain in osteoarthritis and other acute and chronic painful conditions. To determine the potential effects of the new NSAID meloxicam on cartilage integrity, the effects of this drug on proteoglycan biosynthesis in vitro and ex vivo were compared with those of indomethacin, a known inhibitor of sulphated proteoglycans that accelerates joint injury in human osteoarthritis. In vitro cartilage proteoglycan synthesis from a radiosulphate precursor was unaffected by 0.5-10.0 micromol/L meloxicam but was significantly inhibited by 50 micromol/L indomethacin after 6 or 24 h incubation of femoral or tibial cartilage explants in organ culture. This is in accord with previous observations in human or porcine articular cartilage under the same culture conditions. Studies were performed in vivo to establish the effects of the NSAIDs on joint integrity. This involved determining cartilage proteoglycan synthesis ex vivo, leukocyte, fluid and protein accumulation, as well as pain relief. Thus, meloxicam (0.2 mg/kg i.v. x 3 doses) or indomethacin (0.5 mg/kg i.v. x 3 doses) was given for 26 h and the effects were compared with a control (1.0 ml saline i.v. x 3 doses) in dogs in which acute inflammation had been induced by intra-articular (i.a.) injection of calcium pyrophosphate dihydrate (CPPD) crystals into the right stifle joint, an equivalent volume of saline being injected into the left stifle joint as a control. No effects were observed of the treatment with the NSAIDs on ex vivo sulphated proteoglycan synthesis. The lack of the expected inhibitory effects of indomethacin may be related to the relatively low plasma concentrations of this drug obtained during the 26 h period of treatment. The pain response, which was elicited up to 6 h following i.a. injection of CPPD crystals, was totally prevented by the treatment with meloxicam and to a lesser extent with indomethacin. There were no effects from the drug treatment on synovial inflammatory reactions (fluid and cell accumulation), although the protein concentration of the exudate was reduced by meloxicam. This indicates that, at the doses given, it was possible to discriminate the analgesic action from the anti-inflammatory action of the two NSAIDs, this being achieved at relatively low plasma concentrations of these drugs. In conclusion, while relatively high therapeutic concentrations of indomethacin inhibit cartilage proteoglycan synthesis, this is not an effect seen even at high concentrations of meloxicam. Furthermore, the lack of effects on proteoglycan synthesis was evident when these two drugs were given in vivo to dogs. However, the signs of pain, but not the inflammation in the joint, were relieved by low plasma concentrations of the drugs. Meloxicam may thus be safely employed for acute analgesia without the potential risks of joint cartilage damage that occurs with indomethacin given at antiinflammatory doses for long periods of time.