article on arthritis drugs

Even painkillers for dogs have serious risks
By Julie Schmit, USA TODAY
Like pain relievers for humans, pain relievers for dogs are big business, improving the lives of millions.
And like pain relievers for humans, those for dogs have led to heartache.

Pfizer pioneered the market for dog painkillers when it introduced Rimadyl in 1997. Nearly 15 million dogs have taken it, many for pain from degenerative joint disease, or osteoarthritis.

Watch doses, interactions

Proper use of dog pain relievers lessens risks, but proper use isn't always the norm.

Novartis analyzed 1,680 Deramaxx adverse-event reports, including 1,257 osteoarthritis cases.

In 59% of osteoarthritis cases, dogs received doses in excess of the approved dose.

In 28% of all the adverse events, the dog was also on another drug, often aspirin. "This is a definite no-no because mixing can cause serious adverse events," Novartis' David Stansfield says.

Dogs should also be checked before and after receiving NSAIDs, says veterinarian Wayne Randolph of Flemington, N.J. Before he puts dogs on NSAIDs, he does blood work, involving 35 tests at a cost of $65, to check a dog's liver and kidneys, and later repeats the blood work.

The dog NSAIDs are FDA-approved to treat pain and inflammation associated with osteoarthritis. Rimadyl and Deramaxx are also approved to treat post-surgery pain.


Rimadyl now has four competitors with more likely. The market for dog arthritis pain medications tops $130 million a year and is growing about 13% a year, consulting firm Wood Mackenzie says.

But 3,200 dogs have died or been put down after taking the drugs, Food and Drug Administration records show. Almost 19,000 dogs have had bad reactions to them.

The FDA says the drugs are safe, if properly used. Drugmakers say fewer than 1% of dogs have bad reactions to them. If not for the drugs, many dogs might be put to sleep sooner, they say.

"In theory, the drugs are safer for dogs than aspirin," says Steve Marks, head of small-animal medicine at the University of Illinois.

Yet the deaths and other adverse events are a reminder that all drugs pose risks, including those for animals. They also underscore that a drug's risks may not be fully known until the drug is widely sold, despite the FDA's stamp of approval.

Several million dogs received Rimadyl before its warning label was updated to add mention of death in rare cases. No. 2 pain reliever Deramaxx was marketed for a year before its label was so changed.

Despite stronger warnings and other safeguards, the drugs continue to create controversy. Some dog owners and veterinarians say the drugs are being overprescribed by vets who don't always give risk information to owners and who, like doctors for humans, are often educated on drugs by pharmaceutical companies.

"There are no safe drugs. There are only safe doctors," says Robert Rogers, founder of the Critter Fixer Pet Hospital in Spring, Texas. "The large number of adverse events occur with these drugs because veterinarians don't know how to use them." Drugmakers share the blame, he says. Their sales representatives often fail to present adequate risk information.

Adverse-event reports

Through November 2004, the FDA received almost 13,000 adverse-event reports about Rimadyl, far more than for any other dog pain reliever.

Pfizer's database includes almost 20,000 adverse-event reports. The FDA's data include those "possibly" or "probably" linked to the drug. Adverse events for all drugs are believed to be under-reported.

Pfizer won't release Rimadyl's revenue, but it says Rimadyl has the most reports because it's the oldest and biggest dog pain reliever.

Deramaxx has been used by about 1 million dogs since its 2002 launch, owner Novartis says. The FDA's data include 2,813 adverse-event reports for Deramaxx, including 630 dogs who died or were put down.

Rimadyl, with a generic name of carprofen, originated at Roche Laboratories as an anti-inflammatory drug for people. Deramaxx was developed by Novartis for dogs but was discovered by G.D. Searle, where Celebrex originated.

Both Rimadyl and Deramaxx are non-steroidal anti-inflammatory drugs, or NSAIDs, as is ibuprofen and aspirin for humans. Deramaxx is also a COX-2 inhibitor, like Celebrex and Vioxx, the pain reliever for people withdrawn from the market in September because of heart attack and stroke risk.

NSAIDs cause many of the same problems in dogs that they do in humans: Vomiting, diarrhea and ulcers are the most common. Reports of heart problems associated with dog NSAIDs are rare, the FDA says.

Before getting FDA approval, Rimadyl was tested in 549 dogs; Deramaxx in about 700. That's far fewer than the number of subjects in clinical drug trials for human drugs. Erectile dysfunction drug Cialis, for instance, was evaluated in more than 4,000 patients before it got FDA approval.

When it hit the market, Rimadyl was heralded as a "wonder drug" for freeing dogs from pain. Happy, bounding dogs were shown on TV commercials. "No drug in the history of veterinarian medicine has been met with such instant success," says Steve Dale, host of radio show Steve Dale's Pet World.

Rimadyl's fast start had a dark side: Reports of dogs suffering liver damage and other effects began pouring in. One of those dogs was George, a 12-year-old chocolate Labrador retriever owned by Jean Townsend of Johns Island, S.C.

She saw the Rimadyl ads and asked her veterinarian whether Rimadyl could help George, who, while seemingly healthy, was moving slower. Rimadyl seemed to work, but after several weeks, George sometimes couldn't move. He started vomiting and had blood in his stool. Within 30 days of starting Rimadyl, George was put down. An autopsy showed liver damage, ulceration and bleeding.

Warning signs

What to watch for in dogs on non-steroidal anti-inflammatory drugs (NSAIDs):
Vomiting
Diarrhea, black, tarry or bloody stools
Change in drinking or urination
Change in behavior, such as depression or restlessness
Yellowing of gums, skin or whites of eyes

Source: USA TODAY research






"I had no earthly idea I was killing my dog," says the 68-year-old retired government worker.

Townsend says she wasn't warned of the risks and didn't ask, trusting her veterinarian. She refused Pfizer's offer of $249 and filed a lawsuit in 1999 that was joined by 300 others.

Pfizer settled in 2003 to avoid costly litigation, it says. Each plaintiff received about $1,000. Pfizer didn't admit wrongdoing and says it informed the FDA of side effects as soon as they were reported.

"We were incapable of informing the world of what we didn't know," spokesman Robert Fauteux says.

Pfizer updated Rimadyl's label twice, the last time in 1999 noting that death occurred in rare instances. That year, it stopped TV ads. Today's print ads include the death warning.

Owners don't always get info

Deramaxx took a similar path. It went to market in 2002 with a label saying the drug "was well tolerated" with an adverse event rate comparable to dogs treated with placebos. Once again, adverse events after the drug was sold proved otherwise.

Both drugmakers now issue information sheets for dog owners describing the drugs' risks and proper use. Pfizer even attaches the sheet to Rimadyl bottles. But it may not get to consumers because veterinarians frequently repackage drugs into smaller vials. Marks says risk information is rarely discussed with clients. The FDA has said pet owners often complain about not getting the sheets.

Pooter, a 7-year-old black Labrador, went in for a checkup in February, says his owner Vickie McCullen-Main, 52, of Bethel Springs, Tenn. Pooter's veterinarian diagnosed a respiratory infection, prescribed NSAID Metacam and sent him home with a week's supply of Rimadyl and an antibiotic.

The doctor "never mentioned anything at all about the risks," says McCullen-Main. Nor did he check Pooter's blood to make sure he didn't have weaknesses that would make him a bad NSAID candidate.

Pooter started to drool, lost his appetite and bladder control. Thirteen days after his checkup, he was put to sleep. McCullen-Main says Pooter should not have received medication for pain because, "He didn't have pain."

She doesn't want Rimadyl or the other NSAIDs removed from the market. She just wants people to know, "These drugs have risks."

 

Great information there honeybears.
Rimadyl is a great drug, safer than Prednisone when used for arthritis and post surgery patients as long as its used correctly. Most vets that I know of will check the liver enzymes every 6 months, my understanding on that is it will increase disease of the liver of dogs that are pre-disposed to liver problems, it doesnt creat the problem as such. I always tell people who call for refills, if their dog hasnt had bloodwork done they will need to do that but sometimes clients think that is the vets way of 'scamming' money, its not, its a genuine concern for their pet. The report is right though in as much as the information sheet is usually not given to clients, I remember one vet telling me that it will 'confuse the clients and they dont need to have that information'!! I think if it raises questions then the client should have the opportunity to ask those questions. What I like about it can make the dogs a lot more comfortable and its used on an as needed basis (not exceeding 1mg/lb/24 hours) unlike Pred that needs to be tapered down gradually.
As for the Aspirin, I wish people wouldnt give their pets over the counter drugs without checking with a vet first, I dont know how many times we've lost dogs that have literally bled to death because the owners have had them on Aspirin for a month!!
And while were on the subject I might as well throw this in too TYLENOL (gen. Acetaminophen), bad enough for dogs and deadly to cats. Dont EVER give Tylenol to a cat, Ive seen a lot get rushed into the emergency room, usual story is the cat had been limping...or had an abscess!!! and the owner gave it 500mg of Tylenol 20 minutes earlier, the cats have all been in respiratory distress, placed in O2 on entry and usually within a couple of hours or less have gone into seizures and died reagrdless of what life saving attempts have been made. I do know of some cases where the owners gave Tylenol for babies in the liquid form that have lived after treatment.
I posted a link for Tylenol.

http://www.addl.purdue.edu/newsletters/ ... acet.shtml

 

I think its a great general article and eye opener of what to be aware of with side effects and tests that should be done with the dogs on these drugs. I think most go in blindly a lot and dont ask what the benefits/risks are of any trype of treatment. I now research the heck out everything I give both myself and my dogs and cat.

I would never give my pets over counter meds without the vets recommmendation, and even when wylie had hives and the vet told me to just use benedryl and gave me the dose I was nervous.

interesting, it says many dogs are gettng too high of a dose. I wonder why that is.

 

Not really sure how it gets high dosed, Im pretty sure it says on the leaflet what the dosage is.

I did just read up on it and it says it can be given at that dose twice a day....1mg/lb/BID...every vet Ive worked with in the last few years though gives it either once every 24 hours or half that dose every 12 hours (maybe under-dosing on the side of caution??) We started using the injectible form about a year or so ago and the vet told us to make sure we stated on the prescription label not to start oral meds for 24 hours....

 

Thanks Honeybears, for posting that article. I was waiting for that news to come out. I keep Rimadyl on hand for my dogs because of their back/neck problems. I was betting that would come out since the celebrex, vioxx and now bextra problems and I just asked my vet about it a few months ago.