Drug Safety: Equine NSAIDs and Your Horse

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Do you wonder if your horse might suffer some side-effect from an equine? NSAID your vet prescribed' What about long-term use' Dr. Deb Eldredge, Horse Journal Contributing Veterinary Editor, offers some interesting thoughts about drug safety.

On February 22, the FDA (Food and Drug Administration) through their CVM (Center for Veterinary Medicine) branch offered a free webinar on NSAIDs (non steroidal anti-inflammatory drugs) for dogs. Much of the information also applies to our horses and equine NSAIDs. You can download the presentation slides for free here.

Equine NSAIDs are used for controlling pain after surgeries and for pain due to bony arthritis. These drugs are tested for safety and effectiveness. So a drug must be both safe and effective before it is approved for use in your horse. Here is the scary part. Safety studies require the drug be given to 32 healthy, young animals ? in our case, horses. Thirty-two is not a big number. For human studies 10,000 testers are recommended. Perhaps Arabians have a special susceptibility to these drugs, but no Arabians were tested. The problems won?t show up until the drug is on the market and out in the ?real world.?

I admit, I try to avoid using any new drugs of any kind on my animals until they have been out for at least a year. Obviously, if the drug represents a new treatment for a serious problem, I might use it earlier. Otherwise I wait to see what does happen in the real world.

Now, besides being safe, the drug must also be effective in treating the problem for which it is labeled. For these studies generally about 100 patients who are healthy except for the problem being looked at will be treated, along with 50 control animals. These numbers are better, but still not that big a sample.

The CVM veterinarian stated that NSAIDs account for many of the Adverse Event reports they receive. These drugs act to relieve pain and inflammation by acting on prostaglandins. Unfortunately they act on ALL prostaglandins. Your horse has some prostaglandins that protect the stomach lining, help in kidney function and keep platelet numbers at a good level. Other prostaglandins cause pain, inflammation and fevers. While some new human drugs say they are COX 2 selective so they only go after the ?bad? prostaglandins, the FDA feels that this has not been shown in animal medications.

To help owners to identify any side effects their horses develop right away so the medication can be stopped and veterinary care sought, the CVM has companies provide CIS (Client Information Sheets) for these drugs when they are prescribed. This is not required by all states but many veterinarians choose to do so anyway. You can also look for these client sheets on the FDA site or at individual drug company websites. The CIS are written for the average horse owner and don't have all the scientific jargon that a package insert intended for your veterinarian contains.

If your horse is on any NSAID, such as Equioxx, it is worthwhile to check out the CIS. It will help you decide if your horse truly is showing a side effect, if the drug is actually effective for your horse and if you need to contact your veterinarian. You should also file a report so the FDA can keep track of problems.

Article by Dr. Deb Eldredge, Horse Journal Contributing Veterinary Editor