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NSAID's - What Are They and Why Are They Killing Our Dogs?

"Before administering any medication, know what the side effects are. I learned the hard way." -Mel

Rowdy Roo at two months old Rowdy- Two years old

Death by Previcox -Rowdy’s Last Vacation

Thursday, March 29, 2007

Our beautiful, healthy, two year old Labrador Retriever named Rowdy is dead.

He did not die from the impact of the car that struck him and sped away without stopping.* Nor did he die from the lacerations, contusions and hairline fractured pelvis the x-rays revealed. Rowdy died because I violated my number one rule when it comes to prescribed medications for our pets, “Always ask about possible side effects before administering.” This is what I have preached for years to anyone with a listening ear and yet, in my agitated state and wanting to give our dog the needed relief, I neglected to follow my own advice.

This is our experience...

Thursday, March 22, 2007. We were on vacation out of state with our dogs Rowdy and Duke when the accident occurred. The vet said that Rowdy suffered a hairline fracture of the pelvis but that he thought he would be okay. He gave us a bottle containing five tablets of Previcox. Previcox (firocoxib) is a Cox-2 inhibitor and is an NSAID (Non-Steroidal Anti-Inflammatory Drug) produced by Merial Ltd., an animal health subsidiary of Merck and Co. Inc. and Aventis, S.A.

The label stated '1 times daily for 5 days'. No information regarding side effects was given, nor did I have the presence of mind to ask. Little did we realize, that with each pill we were doling out death to our beloved dog.

Friday morning, we dutifully began his doses. Rather than give him a whole tablet (57mg), we chose to administer half in the morning and half that evening so he could rest comfortably at night. Prior to administering the Previcox (firocoxib), he had a normal appetite and drank water as usual.

Saturday morning he refused to eat or drink anything so no pill was given him. Later that evening he seemed to be perking up so again, I offered him food which he ate and water which he drank and drank. I thought nothing of it nor did I give him any of the medication.

Sunday he seemed even better and was so alert, wagging his tail and he actually rolled over for a belly scratch. He tried his best to get up but the fractured pelvis prevented him from doing so without help, so we slipped a long towel around his abdomen and gently lifted him to his feet.

This tried and true method was used long ago on two dogs we found at different times, Gimpy and Jack, who had suffered the same fate. Gimpy's broken pelvis was so severe that the vet said he would have immediately put her down had she been to the clinic that evening. Fortunately for her, it was almost midnight and back then there were no emergency vet clinics anyway.

Gimpy and Jack received low dose aspirin (also an NSAID), for inflammation and pain and both made a full recovery and lived many happy years thereafter. Since Rowdy's injury was nowhere near what Gimpy had suffered and he was progressing so nicely, we opted not to give him any Previcox (firocoxib) on Sunday.

Monday we began our nine hour car ride home so we decided a whole tablet would be necessary for his comfort. Less than an hour later, his breathing became labored and he would stretch out his neck and legs in a rigid manner. Thinking he may have been too warm, we turned down the air conditioning. It seemed to work and again, he drank more than the usual amount of water.

Tuesday came and he seemed very tired. Although he ate and drank, he did not have the stamina to hold himself up while we helped him walk outside. We had to pick him up and carry him back in the house since he would stand in one spot as if he were in a daze. We chalked it up to the grueling car ride the day before.

That evening we gave him one 57mg tablet of  Previcox (firocoxib). By midnight, he was projectile vomiting (Suspect that projectile vomiting is a symptom of poisoning - the body may be aggressively trying to rid itself of a toxin. Drug-overdose patients often experience projectile vomiting. From the article ‘How to Understand Projectile Vomiting’).

Several times during the night and early into the next morning, he vomited until he was physically worn out. He shivered uncontrollably followed by heavy panting and then throwing his head far back, he held his mouth open wide as if trying to draw in more oxygen. Then all four legs would stiffen out straight. He pawed my arm several times in a frantic manner as I lay beside him. By this time his gums were going a greyish colour.

Wednesday morning he was immediately taken to our vet and put on an IV. We were told to check on him at four-thirty that afternoon. Meanwhile, I called Merial, the company that makes Previcox (firocoxib) and told them of the situation. I asked how long until the drug would be completely out of his system and was told eight hours and that there would be no ‘reach back’ residual effects once it was eliminated.

Important: By law, drug companies are required to report adverse effects to the FDA so anyone whose dog has succumbed to Previcox (firocoxib) poisoning, please contact Merial for a case number as soon as possible. Merial's website with phone numbers for all geographic locations is shown below.




The US number to call is: 888.637.4251 (Select option 3)


Having a case number is very important as it helps Merial to track what is happening with their drug and they will update their list of side effects so that other dog owners (and vets) can be made aware of the potential side effects. You may also want to contact your local poison control center and report the drug.   

I then went online and started reading about Previcox (firocoxib) as well as Deramaxx, Metacam, Rimadyl, and other potentially harmful NSAID’s, some of which have been pulled from the market after dogs died from them. We felt certain that the IV would flush his system and that evening Rowdy would be back to his normal self.

We showed up at the vet and were told we could go back and visit him but then they asked us to wait where we were. I thought they may be situating another animal from the surgery room into one of the cages in the back, so never thought anything about it.

The vet came by and asked “Are you here to see the dog that  passed?" We looked at each other dumbfounded as I said "No!" "Not MY dog!" He said Rowdy had died shortly after noon.

Anyone who has experienced a situation similar to this knows the gut punched feeling that accompanies unexpected bad news. We were in total disbelief as we gathered up his lifeless body and brought him home for burial.

The next day I spoke with the same person at Merial who had given me a case number the day before. When I questioned why vets were not given the CIS (Client Information Sheet) regarding NSAIDS, I was told that they could “Send off for the information if they choose to.” Drugs which can and do adversely affect our animals are routinely dispensed without any information. Why is that?

Would it not be good practice for vets to provide their clients with a CIS before prescribing any medication, thus allowing the owner to make an informed decision regarding their dog’s health and well being? My vet had never heard of any dog having a bad reaction to this medication and said he routinely prescribed it since it was one of the “safer” ones. 

"There’s clearly a breach between what veterinarians are reporting and what groups on the Internet contend." Quote from Dr. Larry Glickman (professor of epidemiology and environmental medicine at Purdue University School of Veterinary Medicine) on ProHeart 6, another drug pulled from the market in 2004 after numerous canine deaths.

Previcox's own website under the tab Previcox FAQ states

Which dogs should not take PREVICOX?
Your dog should not be given PREVICOX if he/she:

  • Has had (Merial added the word had to their literature in 2009) an allergic reaction to firocoxib, the active ingredient in PREVICOX.

Please note that almost all pet medications warn against use if the animal is allergic to <insert active ingredient name>. The problem lies with the fact that until the drug is administered, how do you know if your pet is allergic to the main ingredient? Such was the case with Rowdy, a healthy, two year old dog, who had never been on any medication. How could we have known?

An article published in 2006, entitled 'Why is Fido dead? Prescription drugs are killing dogs, too.', named Previcox (firocoxib), along with other NSAID drugs as being responsible for 22,000 cases of illness in dogs, almost 3,000 of which were fatal.

A Previcox ad notes the following,  "In rare situations, death has been reported as an outcome of the adverse events listed above." Really? Are over 3,000 NSAID deaths (and counting) considered 'rare'?

Reports of adverse and fatal reactions to Previcox abound on websites and blogs. Tragic experiences, one after another are cited while the veterinary world by and large has been lulled into thinking that Previcox (firocoxib) is the panacea for all breeds. 

How many deaths are mistakenly attributed to old age or a 'pre-existing condition' while the real culprit is the prescribed drug? According to emails we have received, gastric ulcers, renal failure and heart failure have been linked directly to this drug.

We never thought of other possibilities that might have proved effective for Rowdy. Christie Keith, in her article "What the FDA wants your vet to tell you", shares information as to what vets should be telling their clients, which drugs can safely be used with NSAIDS for gastrointestinal protection and available options instead of NSAIDS.

Our mischievous, loveable Rowdy has now become another statistic, case number 07-18129 in the ever mounting deaths in which Merial claims no responsibility. They responded with, “We are sorry for your loss.”  

Monitor your dog for these possible side effects:

  • Decrease or increase in appetite.
  • Vomiting.
  • Change in bowel movements (such as diarrhea, or black, tarry or bloody stools).
  • Change in behavior (such as decreased or increased activity level, lack of coordination, seizure, or aggression).
  • Yellowing of gums, skin, or whites of the eyes (jaundice).
  • Change in drinking habits (frequency or amount consumed).
  • Change in urination habits (frequency, color, or smell).
  • Change in skin (redness, scabs, or scratching).
  • Unexpected weight loss.

  If you have experienced a positive or negative outcome with Previcox that you would like to share, please include the following information and email to:


  1. Your name and geographic location

  2. Dog's name, age and weight

  3. Why Previcox was prescribed 

  4. Dosage prescribed (57 or 227mg) and how many times daily

  5. Length of time given

  6. Case number from Merial

  7. Photo of your dog

The “Boys”

We had some land that we loved so
And to it often we all would go

As the doors slid open and we watched them run
Our beautiful boys crossed fields in the sun

Rowdy bumped Duke to follow his lead
Duke didn’t mind he followed, indeed

Flushing out a rabbit, it disappeared into thin air
They then tussled with each other, they hadn’t a care

But Rowdy is now gone and Duke wanders alone
A bit unsure of what to do on his own

And now as the doors slide open again
Duke steps out slowly, minus his friend

It is never the same, it never can be
No, life’s not the same without his Rowdy 


If your dog is displaying symptoms of Previcox poisoning and you are not able to immediately take him to a qualified vet, consider using activated charcoal to help rid his system of the toxin.

Email from other owners

Previcox test studies

Mandatory Client Information Sheet

More Previcox Information

Updated December 25, 2009