Guest post by Lorie Huston, DVM
Within the next few months, there will be a new pain medication available for use in cats. Called Onsior®, the new medication has been approved by the FDA and is expected to be available to veterinarians as a prescription product for their feline patients within the next 10 months.
A welcome addition to the limited number of pain medications approved for cats
Because there are very few pain medications that have actually been approved for use in cats, Onsior® is a welcome addition to the arsenal of medications that can control feline pain. Onsior®, once available, will provide veterinarians and cat owners another weapon for relieving feline pain. Currently, when compared to dogs, the number of choices for pain relief in cats is somewhat limited.
According to Onsior’s manufacturer, Novartis Animal Health, “Onsior tablets are indicated to control of postoperative pain and inflammation associated with orthopedic surgery, ovariohysterectomy and castration in cats weighing at least 5.5 pounds and 6 months old. A tablet can be given to cats on an empty stomach prior to surgery and again for the next two days following the procedure.”
A dark cloud in the silver lining for the new pain medication for cats
Onsior® contains, as its active ingredient, a drug known as robenacoxib. Robenacoxib is part of a group of medications known as non-steroidal anti-inflammatory medications, or NSAIDs. Historically, veterinarians have been cautious in using NSAIDs in cats because of the danger of side effects.
NSAIDs have been used extensively in dogs and there are many such canine drugs available, such as Rimadyl®, Etogesic®, Deramaxx®, Metacam® to name just a few. However, in cats, only Metacam® has been approved and widely used. Unfortunately, Metacam® has been responsible for kidney issues in some of the cats that have received the medication. As a result, the FDA placed a warning on the Metacam® label.
The concern with the new drug, Onsior®, is that similar problems might accompany its usage as well. So, while many veterinarians are cautiously optimistic about having a new option to relieve pain in cats, they are also somewhat fearful of the potential side effects of the medication.
Interestingly, both Metacam® and Onsior® have been used in European countries much more extensively for pain control in cats than here in the United States. And there have reportedly been significantly lower numbers of adverse effects with Metacam® than what has been seen here in the United States. The reason for this is unclear. One hypothesis is that the labeling for Metacam® is less restrictive in European countries than it is here in the US. As a result, veterinarians overseas have greater access to educational materials pertaining to the proper use of the medication. Here in the United States, the FDA has strict rules prohibiting the manufacturer of a drug from giving any advice about using the medication in an off-label fashion. As a result, the theory suggests that veterinarians here in the US have more limited access to the proper educational materials and are therefore less apt to use Metacam® in a safe manner than veterinarians overseas.
I’m not sure about the reason for the difference in safety between European countries and the US. Perhaps the theory about education is correct. I have used Metacam® for pain relief in my feline patients on occasion without any adverse effects. However, I have never used the medication in an off-label manner.
That being said, I am happy to see a new medication being made available for pain relief in cats. However, I will probably rely more heavily on choices that I am more comfortable in providing (buprenorphine, tramadol, etc.) until Onsior® has been around long enough and been used in enough cats here in the US to prove itself not only effective but safe as well.
Lorie Huston has been practicing veterinary medicine for over 20 years. Besides a successful career in a busy small animal hospital in Providence, RI, Lorie is also a successful freelance writer specializing in pet care and pet health topics.
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