When it comes to anti-inflammatory drugs for dogs, owners are often concerned about effectiveness and side effects and one common question is whether Metacam is better than Rimadyl for dogs. Both drugs are available by prescription for relief of pain and inflammation and both have a history of being effective. However, they also can cause side effects, especially when given long term. It is therefore informative evaluating whether Metacam is better or safer than Rimadyl and comparing both drugs for effectiveness. This article will provide some studies and insights on what vets have to say about their use.
Non-Steroidal Anti-Inflammatory Drugs
Both Metacam and Rimadyl are non-steroidal anti-inflammatory drugs which means that they they fight inflammation while being free of steroids. When a dog develops inflammation it's because his body is producing prostaglandins, also known as cyclooxygenase (COX), special chemicals responsible for promoting inflammation with its associated redness, swelling, pain and warmth.
On top of promoting inflammation, prostglandins also help protect the dog's stomach lining from the damaging effects of acid and they also dilate blood vessels leading to the kidneys.
Non-steroidal anti-inflammatory drugs work by inhibition of COX , which results in less pain and inflammation. However, since prostglandins have beneficial effects on the stomach and kidneys, their inhibition can cause problems to the dog's digestive tract (decreased protection from the effect of stomach acid) and kidneys (less blood flow to the kidneys), especially when non-steroidal anti-inflammatory drugs are given for extended periods of time. The potential damaging effects certain medications can have on the kidneys is medically known as "nephrotoxicity" while the negative effects on the liver is known as "hepatotoxicity."
Concerns About Side Effects
Many dog owners are concerned about side effects from the use of non-steroidal anti-inflammatory drugs. The side effects may range from mild digestive upset, to stomach ulcers, kidney and liver damage and even death, in some cases.
These side effects are listed in the Client Information Sheet included with the medication and dog owners are instructed to contact their vet immediately if they notice any side effects. Side effects include loss of appetite, vomiting, diarrhea, production of black, tarry or bloody stools, yellowing of mucous membranes, increased drinking and urination.
The use of non-steroidal anti-inflammatory drugs may also unmask hidden pre-existent conditions that may have gone unnoticed due to lack of clinical signs. Veterinarians may therefore recommend regular veterinarian check-ups and blood tests to check for kidney and liver function, before and after use, especially in elderly dogs and dogs who rely on this drug for continuous use.
After acknowledging the potential list of side effects and possible need for routine blood tests, dog owners may therefore question whether some non-steroidal anti-inflammatory drugs may be safer than others. They may therefore wonder whether Metacam is a safer option compared to Rimadyl.
Metacam Versus Rimadyl
Metacam, also known by its generic name meloxicam is a non-steroidal anti-inflammatory drug. To be exact, Metacam is a selective COX-2 inhibitor, meaning that it specifically targets cyclooxygenase-2, COX-2, the enzyme that is responsible for causing pain and inflammation. Since COX-2 is mostly present at sites of inflammation, inhibiting this enzyme means that there are lower risks for stomach ulcers.
Rimadyl, also known by its generic name carprofen, is also a non-steroidal anti-inflammatory drug. To be exact, Rimadyl is a non-selective COX-1 and COX-2 inhibitor, meaning that it inhibits both cyclooxygenase 1 (COX-1), the enzyme that promotes normal gastrointestinal and kidney function, and cyclooxygenase-2, COX-2, the enzyme that provides anti-inflammatory activity.
Studies and Vets' Thoughts
There are many different schools of thought when it comes to choosing one drug over another. For instance, veterinarian Dr. Hunt DVM, feels that Metacam is safer and offers lower chances for side effects affecting the gastrointestinal tract since it's a COX-2 drug, while Rimadyl is a COX-1 and COX-2 inhibitor; however, she points out that, ultimately, they are both non-steroidal anti-inflammatory drugs.
However, it's important to consider that selectivity for COX 2 instead of COX 1, is something that varies from one species and another, and in a study it was found that Rimadyl, despite being a COX-1 and COX-2 inhibitor, showed a strong predilection for selective inhibition of COX-2 versus COX -1. This drug's tendency towards selectivity though has not been consistently supported by all research.
Another consideration is that the way dogs respond to a drug like Metacam and a drug like Rimadyl varies on an individual basis, just as it happens in people, each and every dog may have a different reaction, point out veterinarians Dr. Michele Sharkey, Dr. Margarita Brown, DVM and Dr. Linda Wilmot, DVM in an article on theFood and Drug Administration.
And what about potency? When it comes to effectiveness, both drugs seem to work equally well; indeed, according to a study: "both carprofen and meloxicam provided satisfactory analgesia for 72 hours following ovariohysterectomy in dogs."
"Because the response to pain medication is individualized, no one NSAID is considered more effective than another, and because every NSAID can cause adverse reactions, including stomach/intestinal ulcers and death, none is considered safer than others."~Michele Sharkey et al.
- What Veterinarians Should Tell Clients About Pain Control and Their Pets, by Michele Sharkey, DVM, Office of New Animal Drug Evaluation; Margarita Brown, DVM, Office of Surveillance and Compliance; and Linda Wilmot, DVM, Office of New Animal Drug Evaluation, FDA Veterinarian Newsletter 2006 Volume XXI, No I
- 4. Ricketts AP, Lundy KM, Seibel SB: Evaluation of selective inhibition of canine cyclooxygenase 1 and 2 by carprofen and other nonsteroidal anti-inflammatory drugs. Am J Vet Res 59:11, pp. 1441–1446, November 1998.
- Comparison of carprofen and meloxicam for 72 hours following ovariohysterectomy in dogs.
Leece EA1, Brearley JC, Harding EF., Vet Anaesth Analg. 2005 Jul;32(4):184-92