Meloxicam

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Meloxicam is an approved NSAID for use in cats as an anti-inflammatory, analgesic agent for pain management.

At a dose of 0.1 mg/kg orally (loading dose) followed by 0.05mg/kg once daily as a maintenance dose, it is used for long-term management of arthritis and chronic gingivitis. An injectable version is also available for short-term pain-relieving, such as routine desexing.

In Canada, Europe, Australia and New Zealand, Metacam is marketed as a 0.5 mg/ml product, and is registered for use in cats, whereas the United States version of Metacam is 1.5 mg/ml and is only registered for use in dogs. They also have a 0.5mg/ml version in the U.S.A. for small dogs, but is not registered for use in cats.

The American Association of Feline Practitioners does not recommend using the United States version of Metacam because it is an off-label product and adverse reactions such as acute renal failure and deaths have been reported. The 0.5 mg/ml Metacam has been used safely in Europe, Australia, New Zealand and Canada for many years with few reported reactions. Gastrointestinal side-effects are usually the only signs observed in some cats at doses of 0.01- 0.03 mg/kg daily for up to 6 months[1].

An alternate NSAID, Tolfedine has equivalent anti-inflammatory and analgesic effects to Metacam in cats and is often preferred by feline practitioners because of its better safety record[2]. Note that all NSAIDs should be used with caution in cats because of their low capacity for hepatic glucuronidation, which is the major mechanism of metabolism and excretion for this category of drugs[3]. However, meloxicam is unique in this sense as it is metabolised solely by oxidation, a reliable and predictable pathway of hepatic metabolism in the cat[4].

Meloxicam relieves inflammation and pain in both acute and chronic musculoskeletal disorders. This drug is a non-steroidal anti-inflammatory enolic acid derivative, belonging to the oxicam group of NSAIDs. It has been shown to be cyclo-oxygenase (COX)-2 selective in horses and dogs[5]. Long-term studies in young cats given 0.05 mg/kg meloxicam have been shown to produce no evidence of gross or microscopic evidence of gastrointestinal or renal pathology[6].

Meloxicam acts by inhibition of prostaglandin synthesis, exerting anti-inflammatory, anti-exudative, analgesic and antipyretic effects. It reduces leukocyte infiltration into the inflamed tissue and prevents bone and cartilage destruction. To a minor extent it also inhibits collagen-induced thrombocyte aggregation[7].

Accuracy in dosage is an important consideration. Meloxicam should not be used in chronic renal disease, pregnant or lactating cats, or those suffering from gastrointestinal disorders such as gastritis, diarrhoea, impaired hepatic, cardiac or renal function and haemorrhagic disorders or where there is evidence of individual hypersensitivity to the product[8].

As for all NSAIDs, use in an animal less that 6 weeks of age or in debilitated aged animals may involve additional risk. If use in such animals cannot be avoided careful clinical management may be necessary.

Other NSAIDs, diuretics, anticoagulants, aminoglycoside antibiotics and substances with high protein binding may compete for binding and thus lead to toxic effects. Meloxicam must not be administered in conjunction with other NSAIDs or glucocorticosteriods. Concurrent administration of potential nephrotoxic drugs should be avoided.

Pre-treatment with other anti-inflammatory drugs prior to the use of Meloxicam may result in additional or increased adverse effect and accordingly a treatment-free period with such drugs should be observed for at least 24 hours before commencement with Meloxicam. The treatment-free period however, should take into account the pharmacokinetic properties of the drugs previously used.

Typical adverse reaction of NSAIDs include anorexia, vomiting, diarrhoea, faecal occult blood and apathy. These side effects are in most cases transient and disappear following termination of treatment, but in rare cases may be serious.

Hypovolaemic or hypotension should be corrected prior to use of the product.

References

  1. Gunew MN et al (2008) Long-term safety, efficacy and palatability of oral meloxicam at 0.01-0.03 mg/kg for treatment of osteoarthritic pain in cats. J Feline Med Surg 10(3):235-241
  2. Benito-de-la-Víbora J et al (2008) Efficacy of tolfenamic acid and meloxicam in the control of postoperative pain following ovariohysterectomy in the cat. Vet Anaesth Analg 35(6):501-510
  3. Lascelles BD et al (2007) Nonsteroidal anti-inflammatory drugs in cats: a review. Vet Anaesth Analg 34(4):228-250
  4. Grude, P et al (2010) Excretion mass balance evaluation, metabolite profile analysis and metabolits identification in plasma and excreta after oral administration of [14C]-meloxicam to the male cat: preliminary study. J Vet Pharmacol Ther 33(4):396-407
  5. Brideau, C, Van Staden, C & Chan, CC (2001) In vitro effects of cyclooxygenase inhibitors in whole blood of horses, dogs and cats. Am J Vet Res 62:1755-1760
  6. Dammgen, J (2007) The use of Metacam 0.5 mg/ml oral suspension in cats with osteoarthritis. In: Metacam symposium on arthritic disease in cats. pp:19-20
  7. Lees, P., et al (2004) Pharmacodynamics and pharmacokinetics of nonsteroidal anti-inflammatory drugs in species of veterinary interest. J Vet Pharmacol Ther 27:479-490
  8. Lees, P., et al (2004) PK-PD integration and PK-PD modelling of nonsteroidal anti-inflammatory drugs: principles and applications in veterinary pharmacology. J Vet Pharmacol Ther 27:491-502