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THE PET PHARMACY
By Wendy C. Brooks, DVM, DipABVP
Educational Director, VeterinaryPartner.com

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Meloxicam (Metacam)

Brand Name: Eloxioral, Loxicom, Melonex, Meloxidyl, Metacam, Mobic, Mobicox, Orocam

Available in 7.5 & 15 mg tablets (human formulations) transmucosal spray & two strengths of oral suspension (veterinary formulations)

Background

Meloxicam is a member of the class of drugs known as non-steroidal anti-inflammatory drugs NSAIDs), the same class as such common over-the-counter remedies as Advil (ibuprofen), Aleve (naproxen), Orudis (ketoprofen), and aspirin as well as more controversial prescription drugs such as Celebrex (celecoxib) and Vioxx (rofecoxib). This class of drug is used for pain relief successfully in humans but the development of safe NSAIDs for dogs has only been achieved relatively recently and continues to be problematic in cats. With the possible exception of aspirin, none of the human drugs listed above can be safely used in pets and even aspirin has its issues.

The problem with NSAID use in pets has been unacceptable (even life-threatening) side effects. Concerns have related to:

  • Stomach ulceration - even perforation and rupture of the stomach can occur. This is not only painful but potentially lethal.

  • Platelet deactivation - platelets are the cells controlling the ability to clot blood and, as a general rule, it is preferable not to promote bleeding. We would prefer platelets to remain active and able to function should we need them.

  • Decreased blood supply to the kidney - this could tip a borderline patient in to kidney failure.

The veterinary profession had been in need of an NSAID that could effectively relieve pain without the above risks. Meloxicam is a human NSAID that turns out to offer important safety aspects to both dogs and cats.

This new plane of safety is made possible by new scientific knowledge. Many of the biochemicals responsible for the pain and inflammation we want to allieviate are produced by an enzyme called cyclo-oxygenase 2. The goal is to inhibit this enzyme without inhibiting its counterpart cyclo-oxygenase 1. Both enzymes produce prostaglandins but we want to keep our constitutive prostaglandins that help maintain our bodies (these come from COX-1) but not make the inflammatory prostaglandins that come from COX-2. NSAIDs like aspirin inhibit all COX enzymes, good and bad alike. Most human bodies are okay with this but most dogs and cats are not.

Meloxicam is what is called a COX-preferential NSAID, which means that it inhibits COX-2 much more strongly than COX-1 and this new plane of safety has enabled dogs to have long-term, orally administered pain relief with minimal side effects potential. Many canine lives have been extended with good quality because of the advent of this class of pain relief.

How this Medication is Used

Meloxicam is generally given to control arthritis pain in dogs although it can be given for many other painful conditions such as injuries, cancer, surgery, dental infections, and more. In dogs, it is typically given as a once a day as a pleasantly flavored liquid. The veterinary approved product comes with a special dosing syringe marked to show how much to give for the pet's weight (rather than in milliliters as most syringes are marked).

Feline use of meloxicam is of some controversy. In Europe, Canada, Australia and New Zealand, long-term use of the 0.5 mg/ml meloxicam formula in cats is registered, approved, and heavily marketed; however, this formula is not legally approved for cats in the United States. Further, the manufacturer has specifically discouraged feline use of meloxicam beyond its approved use in the U.S. (one dose for post-surgical pain relief). This paradox of marketing the product one way for most of the world and another way in the U.S. has been frustrating as there are substantially fewer oral pain relief options for cats available compared to what is available for dogs. Meloxicam is still used by many veterinarians for cats but the advent of robenacoxib has provided a less controversial feline NSAID. Furthermore, there are other medications and supplements for feline pain relief that can be combined into a less controversial regimen.

Side Effects

Stomach upset: vomiting, diarrhea, and/or appetite loss are the important side effects to watch for, especially in the three weeks or so after beginning long-term meloxicam. These symptoms can have multiple meanings so it is important to sort them out.

  • Some pets are simply sensitive to NSAIDs despite the COX-preferential nature of meloxicam. These pets simply need nausea relief in the short term and a different pain management regimen after recovery.

  • Some dogs have an unrecognized liver problem. Meloxicam is removed from the body by the liver, which means that a liver on meloxicam has extra work. This is not a problem for a normal liver but a diseased liver could be tipped into failure from the extra load. This is why screening tests are so important prior to long-term use.

  • Another problem manifesting with upset stomach is an idiosyncratic hepatopathy (a liver condition that is not dose-dependent or predictable in any way). While this only occurs in 1 in 5,000 dogs, it is a more serious problem that likely would require hospitalization.

  • Altered kidney function (especially in cats) is a concern with any NSAID and might also manifest as an upset stomach. This is another reason why pre-screening of kidney function before long-term use is especially important before beginning meloxicam

If a pet on meloxicam develops an upset stomach, discontinue the medication and report the problem to your veterinarian. It is prudent to check liver enzymes and kidney function (a blood test) to rule out the two liver side effect issues and kidney issues that could be seen with an upset stomach.

Other side effects typically require other pre-existing conditions that could be made worse by giving an NSAID (even a COX-preferential one). See the Concerns and Cautions section.

Interactions with other Drugs

Drugs of the NSAID class should not be used concurrently as the potential for the aforementioned side effects increases. For similar reasons, NSAIDS should not be used in conjunction with corticosteroid hormones such as prednisone, dexamethasone, etc. A 5 to 7 day rest period is recommended when changing from one NSAID to another. Aspirin poses an exception due to its strong platelet inactivating abilities so 10 to 14 days is recommended when switching to another veterinary NSAID from aspirin. Allow at least one week between prednisone and meloxicam.

ACE inhibitors such as enalapril, or benazepril may not be as effective when taken with meloxicam. (ACE inhibitors are used to treat hypertension or heart failure.) This is because ACE inhibitors depend on the dilation of blood vessels in the kidneys and such dilation can be interfered with by NSAIDs.)

Concerns and Cautions

Meloxicam works as well when given on an empty stomach as when given on a full stomach. If a patient has had some upset stomach issues with meloxicam these can often be minimized by administering the drug on a full stomach.

Maximum effect is seen approximately 8 hours after administration. When beginning a trial course of meloxicam, a response may take 3 or 4 days to show. If no response has been seen in 10 days, meloxicam has failed and a different pain medication should be tried. If one NSAID fails, another may well work.

The veterinary formulations of meloxicam are oral liquids (either 1.5mg/ml or 0.5 mg/ml). The liquid formulation allows for accuracy in dosing. The human tablets are available in much higher strengths and will be inappropriate except possibly for very large dogs. It is important not to use human medications on pets unless your veterinarian has provided detailed dosing instructions.

Meloxicam should not be used in pregnancy or in lactation.

Meloxicam can be used in cats but with caution (see above regarding use in countries outside the U.S.). The original oral solution of meloxicam was commonly dosed in drops from the bottle. Since the wrong dose of meloxicam can be very dangerous for cats, it is important not to drop the drops directly into the cat's mouth from the bottle as squeezing too strongly could easily deliver an overdose. The low dose (0.5 mg/ml) formula can be dosed with the provided syringe.  In the cat this product is given either as a single one time injection in association with surgery (its FDA approved use) or long term 2-3 times per week (its non-U.S. dose). Long term use of this product in cats is "off label" in the U.S.

As with all veterinary NSAIDs periodic monitoring tests are important to check liver enzymes and kidney function, and to generally screen the patient's health. Typically an every 6 months schedule is recommended for dogs. There is no general consensus on what is appropriate for cats but because of feline sensitivity towards NSAIDs, feline monitoring is especially important. If you are using this product in the cat, be sure you understand what monitoring schedule your veterinarian is recommending for your specific pet.

Patients being considered for long term meloxicam use should be evaluated with a complete physical examination and initial screening blood test to identify any factors, such as liver or kidney disease, that might preclude the use of this or any other NSAID.

Meloxicam should not be used in puppies under 6 months of age or kittens under 4 months of age (safety has not been proven).

Meloxicam should be avoided, if possible, in patients with impaired function of the liver, kidney or heart. It should also be avoided in dehydrated patients and patients with known GI ulcers.

Always shake the bottle of meloxicam before drawing up the dose.

For More Information

The manufacturer of veterinary meloxicam, Boehringer Ingelheim, offers more information.

See information on veterinary non-steroidal anti-inflammatory drugs from the Food and Drug Administration (FDA).

It is our policy not to give dosing information over the Internet.

 

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