by Michele Sharkey, DVM, MS, Office of New Animal Drug Evaluation; Margarita Brown, DVM MS, Retired, Office of Surveillance and Compliance; and Linda Wilmot, DVM, Retired, Office of New Animal Drug Evaluation

Non-steroidal anti-inflammatory drugs (NSAID) are commonly prescribed and are effective pain control drugs for pets. Like most drugs, they do cause side effects, some serious. Veterinarians are in the best position to inform their clients about these side effects, so the clients can take better care of their pets. And, pet owners expect veterinarians to explain all potential risks of medications.

Dogs are living longer and healthier lives thanks to advances in veterinary medicine and pharmaceuticals. With active lifestyles that extend into advanced ages, dogs are often diagnosed with osteoarthritis or undergo surgical procedures and are treated for postoperative pain. NSAIDs are among the most common analgesics prescribed in these cases.

NSAIDs are used to control signs of arthritis, including inflammation, swelling, stiffness, and joint pain. Inflammation—the body’s response to irritation or injury—is characterized by redness, warmth, swelling, and pain. NSAIDs mediate the production or function of prostaglandins (enzymes) involved in inflammation.

In the United States, NSAIDs approved for use in dogs include:

Table 1: Some FDA-Approved Nonsteroidal Anti-Inflammatory Drugs for Dogs

*Indicates an FDA-approved generic animal drug.

In the United States, there is one NSAID approved for up to 3 days use in cats: ONSIOR (robenacoxib) tablets or ONSIOR (robenacoxib) injection. Meloxicam injection is approved for a single injection to control pain associated with surgery in cats.

You can get more information about NSAIDs approved for use in animals in the US by going to Animal Drugs at FDA, and then the “NSAID Labels” navigational button under Supporting Documents, where you can look up the drugs by their brand names or active ingredient.

Other NSAIDs are available in the United States for human uses but have not been approved for use in dogs or cats. Sometimes there may not be an approved animal drug available for a specific indication or dosage form. However, the Animal Medicinal Drug Use Clarification Act of 1994 gives veterinarians the same kind of discretionary authority available to physicians, allowing veterinarians, under certain conditions, to prescribe drugs for “extralabel” uses, which are uses not listed on the label.

As with any medication, veterinarians should discuss the benefits as well as the risks of the drugs with their clients when prescribing an NSAID. Every year millions of doses of medications are prescribed for dogs with good reason—but many adverse reactions occur. Most adverse reactions are mild, but some result in permanent impairment or even death. If the client can recognize a possible reaction and stop the medication while seeking veterinary attention for the dog, quick action may make the difference between a good outcome and a disaster.

The most common side effects from NSAIDs include vomiting, loss of appetite, depression/lethargy, and diarrhea. Some side effects can be serious, especially if the drug is not used according to labeled directions, resulting in the need for medical care. Serious adverse reactions include gastric ulcers and perforations, kidney and liver problems. Death may result in some instances.

All NSAIDs approved for oral use in dogs and cats come with a Client Information Sheet (also known as the Information for Dog (Cat) Owner Sheet) that describes the drug’s side effects. Dog and cat owners should ask veterinarians for the Client Information Sheet when an NSAID is prescribed. These Client Information Sheets provide the pet owner with important information in a user-friendly manner regarding what can be expected from use of the drug, potential side effects, and the need to seek veterinary attention if problems occur. By accompanying each NSAID prescription with the Information for Dog (Cat) Owner Sheet, a handy reference of valuable safety information and drug company contact information is readily available to the owner.

Not all side effects can be predicted

All approved medications indicated for pets are subject to extensive evaluation by a drug company using stringent standards set by the CVM before they are marketed. Every effort is made to ensure safe and effective treatments. However, every drug has the potential for side effects. Pre-testing by the animal drug manufacturer and review of the data from those tests by the government ensure that the animal drug is safe and effective. Because of the relatively low frequency of some adverse events, some adverse effects are recognized only after the marketing of the product in a large population of animals.

NSAID therapy can also unmask hidden disease, previously undiagnosed due to the absence of apparent clinical signs. Dogs with underlying kidney disease, for example, may experience worsening of that disease while on NSAIDs. Dogs at greatest risk for kidney problems are those that are dehydrated, on concomitant diuretic therapy, or have kidney, heart, and/or liver dysfunction.

Unexpected reactions to a drug are reported to the drug manufacturer, and every reaction reported to a pharmaceutical manufacturer must by law be reported to the FDA.

Advice given to owners

We recommend that pet owners work with their veterinarians to make medication decisions including the use of over-the-counter drugs, vitamins, herbal supplements, flea control products, and other medications. Giving certain medications and other over-the-counter products at the same time could be detrimental to a dog’s health.

Many reactions due to NSAIDs may be lessened if owners are aware of potential side effects, and with appropriate use many can be minimized or avoided. First and foremost, if an owner suspects a reaction to an NSAID, the owner should stop administering the drug immediately and should contact a veterinarian. Some reactions are mild and go away after stopping the drug.

The veterinarian is in the best position to advise the dog owner on using an NSAID. Before administering an NSAID to a dog, the veterinarian often recommends blood tests. The knowledge gained from these tests could be critical in deciding if the drug is safe to use in a dog. If a dog is prescribed an NSAID for the control of pain associated with osteoarthritis, regular veterinarian check-ups and blood tests are recommended to evaluate the continued use of the drug.

When treating a dog with an NSAID, the owner should never increase the dose or frequency of administration without consulting their veterinarian.

The owners should follow their veterinarians’ instructions.

A pet owner should never give an NSAID to a dog (or cat) unless under the direction of a veterinarian.

Pain control in response to the use of an NSAID varies between dogs (just as it does in people). 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.

But selecting the best NSAID is important. With advances in the recognition and definition of animal pain and the many NSAID choices available, much benefit can be gained from the appropriate and careful use of these drugs.

Sometimes, the process of finding the best NSAID for a specific patient can mean changing the prescription. Only one brand of NSAID should be administered to a dog at any given time. If at some time the owner and the veterinarian decide to try a different NSAID, a wash-out period is recommended. A wash-out period is a period of time recommended by the veterinarian during which the dog does not receive any NSAID. This allows one NSAID to be cleared from the body before starting another NSAID. Then the dog can be switched to another NSAID. NSAIDs should not be combined with the use of a corticosteroid, either.

The pain associated with osteoarthritis may wax and wane. The lowest effective dose should be used for the shortest duration depending on the dog’s response. If the dog seems to improve to the point of not needing the drug, the owner should discuss continued use of the NSAID with a veterinarian.

The key to making any transition or change work well is good veterinarian-client communications.

An informed dog owner is the best defense against serious side effects from NSAIDs. The veterinarian is the most qualified source for information regarding NSAID use and a dog’s care. Owners should not hesitate to ask questions and inquire about possible side effects or signs to watch for when treating a dog. A Client Information Sheet, which a veterinarian should give the pet owner whenever an NSAID is prescribed, serves as a reminder of this information for use at home.

What starts out as a minor problem can readily progress to an emergency. An owner should be encouraged to call his or her veterinarian with any concerns about the NSAID the dog is receiving. The veterinarian and/or owner may even call the drug manufacturer (a toll free number appears on each label and the Client Information Sheet). Pharmaceutical companies offer customer service and technical support for product information and quality control. When possible problems are experienced with a product, the manufacturer may have specific recommendations for the treating veterinarian regarding tests and treatments.

Package inserts and Client Information Sheets for many of the NSAIDs used in dogs, cats, and horses may be found at the NSAID Labels page of Animal Drugs @FDA.