The Painful Truth
Nov 2007
By Heidi Sherburne
The importance of blood work and knowing the side effects of medications
Heidi and Timber
He was young and vibrant—and my best friend. I never dreamed I would have to say goodbye to him before he was gray-haired and more apt to take a nap than chase a ball, but his life was cut short following an elective surgery. Ironically, the surgery had been a success and it was the treatment meant to keep him comfortable afterward that led to his death one week later. If I’d known then what I know now—the importance of pre-surgery blood work and the potential side effects of the pain-relieving medication—he might still be alive today.
Timber, a 4-year-old yellow Lab, was full of life. He loved to swim and romp in the woods. After watching him cope with a chronic orthopedic injury, I consulted with several veterinarians and elected for surgery to relieve his discomfort and increase his quality of life. The procedure was a success and he enjoyed an active life again—until he sustained another injury. After weighing the pros and cons of a second surgery, I decided that it was indeed the best option, especially since he was still a young dog.
Just as he was after the first surgery, Timber was sent home with a pain medication belonging to a class of extremely effective pain control medications called non-steroidal anti-inflammatory drugs or NSAIDs. According to the Federal Drug Administration (FDA) Center for Veterinary Medicine (CVM), NSAIDs are often used to help control symptoms of arthritis, such as swelling, stiffness and joint pain, and may also be prescribed to control pain and inflammation following surgery. Timber was prescribed Rimadyl. Veterinary NSAIDs approved for use in dogs include Etosgesic, Rimadyl, Metacam, Deramaxx, Previcox, Zubrin and Novox.
Initially, Timber did well following the surgery. Although he was under strict orders to remain quiet, he was alert and ready for action. Four days later, however, he vomited and didn’t seem interested in his food. I chalked it up to his breed, a Lab—he probably ate something he shouldn’t have. He was still begging for biscuits so I tried not to worry. Still, I called the veterinary clinic and it was decided that Timber was most likely reacting to the antibiotic, so it was removed from his post-op drug regimen. However, the vomiting continued and Timber started refusing food entirely, which was unusual.
During this time, Timber remained on the pain medication—after all, I wanted him to be comfortable. I had no reason to believe that it might be the cause of his sickness. In fact, Timber had been prescribed an NSAID once before, and although he was only on it for two weeks, he didn’t appear to have any problems. I had been warned by a friend that this particular medication had the potential for side effects. However, that warning had been a couple years earlier and along with my foggy memory of it, I assumed the side effects were probably related to its long-term use in older dogs.
Six days after surgery I took Timber back to the veterinary clinic. The blood work showed his liver enzymes were at dangerously high levels. Without food, he had stopped vomiting, but he had become jaundiced—his gums and skin turned a dark yellow, a sign his liver was not working properly, and waste products were building up in his bloodstream. He was placed on intravenous fluids to flush his system.
After two days at the vet clinic, Timber took a turn for the worse. He began vomiting blood, and although another blood test showed his liver counts had dropped from the initial high levels, his digestive system had been damaged and his blood had stopped clotting. Timber had gone into shock and there was no recourse. My beautiful, healthy, 4-year-old dog was dying in front of me and with no option but euthanasia, I watched him slip into another world that was no longer ours together. I was grief stricken, and filled with endless questions about how this could happen. I also found a determination to prevent this tragedy from happening to others.
I began researching pain relief medications and learned that NSAIDs have the potential for very serious side effects. They include vomiting, loss of appetite, jaundice, liver toxicity, diarrhea, gastrointestinal bleeding, changes in drinking habits, dark stool—indicating blood in the digestive tract—and even death. In fact, at the request of the FDA, death was added as a side effect on the first NSAID label in 1999. The NSAID was Rimadyl and it was the first FDA approved NSAID for use in dogs. The addition of death as a side effect was based on the adverse drug experience (ADE) reports received by the FDA in 1998. Of all the ADE reports suspected to be caused by Rimadyl that year, 13 percent involved death of the dog.
Also at the FDA’s request, Pfizer, the company that manufactures Rimadyl, developed information sheets to be provided with the medication when dispensing it, so owners are made aware of potential drug toxicity. According to the FDA, all NSAIDs approved for oral use in dogs now come with a client information sheet. This was information I did not receive when I brought Timber home from the vet, and I did not know how critical the information would be.
A post-mortem examination performed by the vet, along with multiple tissue samples studied by a pathologist, concluded with little doubt that the pain medication was the root cause of Timber’s death. No signs of pre-existing conditions, diseases or cancer were evident—it was obvious that his liver had been severely damaged, and that the NSAID was the culprit.
In my continued research after Timber’s death, I learned from the FDA that adverse reactions to NSAIDs occur most often shortly after administration. Notably, if symptoms are caught early enough, animals usually recover. Sadly, most owners who reported the adverse drug experiences directly to the FDA were not made aware of the potential side effects—and 10 years later, many owners are still not being informed. According to the FDA, “An informed dog owner is the best defense against serious side effects from NSAIDs.” One state, Pennsylvania, agrees and has taken action. Senators there have introduced legislation mandating that veterinarians provide clients with information sheets for prescribed medications whenever they are available.
Both the FDA and the Rimadyl information sheet recommend appropriate laboratory tests and blood work before and during administration. This establishes baseline health data and may potentially rule out pre-existing conditions that might be exacerbated by the medication. The FDA strongly recommends that a baseline be established.
I had been given the option to have baseline blood work done for Timber before his second surgery, but opted not to have it done because I didn’t realize its importance. He appeared healthy and fit and because his first surgery, less than a year before, had gone so smoothly, I had no reservations about his ability to handle the second surgery. It was a missed opportunity and a decision that, in hindsight, could have saved his life.
It is possible that a blood test before Timber’s surgery would have revealed that his liver was somehow impaired and a post-op treatment with an NSAID would not have been advised. Alternatively, knowing that his liver was healthy before surgery, which the vet had no reason to believe it wasn’t, would add evidence to the case that Rimadyl was the sole cause of Timber’s failed liver and subsequent death. It is vital information we will never know.
While there is no guarantee blood work will detect the potential for an adverse drug reaction, it is best to cover all bases. Blood work may be easy to dismiss if you have a young healthy dog, but it is simply not worth the risk. It reflects the health of a dog, as well as his ability to handle certain medications. It is important to remember that an animal’s instinct is to appear healthy so they will often mask an illness.
Knowledge of the potential side effects of NSAIDs was the second missed opportunity for saving Timber. Had I received the client information sheet and known that vomiting and loss of appetite were signs to look for—and that early detection can lead to recovery—it is possible he might be alive today. Always ask your vet for a list of potential side effects when a medication is prescribed and never hesitate to call if your dog begins to show signs of any reaction.
We are the guardians of our pets. It is imperative that we understand the side effects of medications and act immediately if they arise. You are the best judge of your dog’s behavior and if something seems wrong, trust your instinct, call your veterinarian and push for action. A minor problem can quickly escalate into an emergency if symptoms aren’t taken seriously. It’s better to overreact than not react quickly enough when your best friend’s health is at stake.
It is difficult to live with the knowledge that I was giving my dog a medication that was killing him, even if I didn’t know it at the time. It is my sincere hope that this information will prevent the same situation from repeating itself again.
