http://www.veterinarypartner.com/Content.plx?P=A&A=1752 Basically this article says that if nausea, appetite loss, vomiting or diarrhea occur while on metacam, use should be discontinued because it could be affecting the liver and kidneys... The most common side effects of meloxicam are nausea, appetite loss, vomiting or diarrhea. If any of the above are noted, meloxicam should be discontinued and the dog brought in for a liver enzyme and renal parameter blood test. In most cases, the reaction is minor and resolves with symptomatic relief, but it is important to rule out whether or not the patient has more than just a routine upset stomach.
If a patient has borderline kidney function, NSAIDs should not be used as they reduce blood flow through the kidneys. It is also important that NSAIDS not be given to dehydrated patients because of this potential side effect.
The Hepatopathy Side Effect (usually occurs within the first 3 weeks of use)
A carprofen reaction that has received special attention is hepatopathy, a type of liver disease. Symptoms include nausea, appetite loss, and/or diarrhea as well as marked elevations (3-4 times higher than the normal range) in liver enzymes measured in the blood. The question of whether other veterinary NSAIDs share this reaction has arisen. At this time, it is generally felt that the hepatopathy idiosyncratic reaction is not unique to carprofen and should be of concern with any veterinary NSAID.
Dogs with this syndrome show improvement with support 5 to 10 days after discontinuing medication. It is important that the NSAID be discontinued and the patient evaluated in the event of upset stomach signs in case of this syndrome. Even though this is a rare syndrome (one in 5000), it can become life-threatening if ignored. Appetite loss or other intestinal signs do not necessarily indicate a hepatopathy but since they might, it is important not to ignore these signs should they occur. There is no way to predict which dogs will experience this side effect.
The hepatopathy reaction usually occurs in the first 3 weeks after starting carprofen but could theoretically occur later.
All NSAIDs are removed from the body by the liver. If the patient’s liver is not working normally due to another disease or if the patient is taking other drugs that are also removed by the liver, it is possible to “over work” the liver and exacerbate pre-existing liver disease. If there is any question about a patient’s liver function, another class of pain reliever should be selected.