Joint and Bone Pain
Historically it was thought that animals did not feel pain or that they handled pain differently to humans. Scientific studies have given veterinarians a better understanding into how dogs feel and react to pain. It has been established that animals and humans have similar neural pathways that develop and transfer pain signals and neurotransmitters. A decade ago, pain relief for dogs was almost non existent. Old dogs limped around suffering joint pain and little could be given to relieve pain associated with injuries or following operations. Treating pain in dogs was limited to drugs that were designed for humans.
Joint pain occurs through bone abnormalities such as hip dysplasia, injuries or through the ageing process. The joint cartilage (protective covering for bones) roughens and cracks which exposes the bone making it more susceptible to further erosion.
The body automatically uses physiological mechanisms to try and repair the damaged tissue. The body increases blood flow to deliver extra nutrients and oxygen to the damaged area to assist cellular repair. This causes swelling which in effect adds pressure to the damaged site. The surrounding cells release chemical substances that act on the nerve endings. Prostaglandins, formed from polyunsaturated fatty acids, are released by the cells (prostaglandin synthesis) which stimulate pain receptors that transmit pain signals to the brain. To prevent pain, anti-prostaglandin drugs work by inhibiting prostaglandin synthesis.
If pain is left untreated in dogs, it decreases their quality of life and can hinder post-operative recovery. A fundamental part of veterinary treatment involves preventing and managing pain.
Veterinarians are trained to recognise, assess, prevent and treat pain in dogs as part of patient care. Unfortunately many dogs do not show obvious signs of pain so veterinarians are trained to ask the owner the right questions to enable them to make the correct diagnoses and prescribe adequate pain relief. Once the source of pain has been identified, drugs are used to relieve discomfort. For arthritic pain associated with Osteoarthritis and other bone and joint disorders, Non Steroidal Anti Inflammatory Drugs (NSAID's) such as Rimadyl, Metacam, Deramaxx and Zubrin are prescribed.
Pfizer pioneered the market for painkillers designed for canines when the company released Rimadyl (generic name Carprofen) in 1997. The drug was geared to controlling arthritic pain in dogs and was hailed as a “wonder drug”. American TV commercials showed happy dogs bounding around and geriatric dogs becoming more mobile with a better quality of life. Steve Dale, the host of the radio show, “Steve Dale's Pet World” said:
"No other drug in the history of veterinarian medicine has been met with such success”.
Rimadyl was Pfizer's most successful advertising campaign until the launch of Viagra in 1998.
Rimadyl (Carprofen) began with a Swiss company, Hoffman La Roche. Roche produced a drug called Imadyl that did not carry the risks of causing Peptic ulcers. A pharmaceutical journal noted impaired liver function in 14%-20% of test subjects and advised that Carprofen needed more testing and in the meantime well-established drugs such as Aspirin should continue to be used.
In 1983 the drug was launched with the slogan; “Safer than Aspirin” but for unknown reasons the popularity of the drug never took off and it was withdrawn to sit in Roche's Animal Health Laboratories.
SmithKline Beecham bought Roche's Animal Health in 1993. Deciding to focus on human health alone, SmithKline Beecham sold their Animal Health division to Pfizer in 1995. By as early as October 1996 Pfizer had obtained FDA/CVM approval for Carprofen (Imadyl) and in January 1997, with a multi-million dollar advertising campaign, Rimadyl was launched.
Advertisements showed a pre-Rimadyl Labrador bounding over a fallen tree and another dog leaping through a window. The campaign included 1,785 printed stories, 856 radio reports and 245 TV news reports which generated 25.5 million positive impressions of Rimadyl. Vets were being given “points” for each purchase of Rimadyl. These points could be collected and exchanged for Palm Pilots, Zip drives for computers or for other equipment. (Surely this is a conflict of interest, health of patients versus personal material desires?!)
All too soon it was becoming clear that actually Labrador Retrievers were suffering side effects form taking Rimadyl. Liver Necrosis in Labrador Retrievers has been reported in the largest number of all breeds suffering adverse reactions. All of the NSAID drugs have the potential to cause liver failure and unfortunately blood tests before administering the drugs cannot predict whether the reaction will occur.
The Food and DRUG Administration (FDA) were flooded with reports of dogs of all breeds suffering side effects and becoming ill or being euthanized after taking the drug. To put this into perspective:
The FDA received 3,000 reports of adverse reactions to drugs in animals in 1996. In 1998, one year after the launch, Rimadyl had caused this many adverse reactions alone.
By March 13th 2000, the Wall Street Journal carried a report by Chris Adams called:
"Most Arthritic Dogs Do Very Well On This Pill, Except Ones That Die.”
One case mentioned was a six year old Siberian husky taken to the vet with slight lameness and stiff limbs. The dog was prescribed Rimadyl and for a short time its condition improved. Then suddenly the dog had loss of appetite, vomiting and seizures and was put to sleep. An autopsy revealed liver damage associated with an adverse drug reaction.
Another owner, Jean Townsend from South Carolina , saw her dog George, a 12 year old Labrador ; suffer tremendously before having to be euthanized. Jean asked her vet about Rimadyl after seeing the adverts on TV. George was beginning to show a sign of advancing old age but apart from this was in good health. She was sure that Rimadyl had an adverse effect on George which led to him being euthanized on October 13th 1997.
Jean brought a class action law suit against Pfizer in 1999, two years after George died, alleging that after approval by the FDA Rimadyl was launched without a complete understanding of the side effects that could result from the drug. Jean was offered $249.33 settlement by Pfizer with a condition that the settlement remained confidential. This was refused by Jean.
The report highlighted other cases of adverse reactions in dogs being given Rimadyl. It also revealed that pet drugs were worth around $3 billion world wide and that Rimadyl was one of the bestsellers bringing Pfizer Inc. tens of millions of dollars in sales.
Faced with so many complaints the FDA insisted that Pfizer must cite the word “death” as a possible side effect which Pfizer agreed to. However Pfizer would not agree to include the word death in their television commercial, indicating that to do so would be devastating for the product. Instead they stopped the commercial. Pfizer turned to the labelling for Rimadyl and decided to attach “Client Information Sheets” to each package, a practise hitherto unknown by the FDA or drug companies.
The client information sheet can be viewed on the FDA's website via THIS link or at the Rimadyl website.
Side effects to be aware of are:
- Loss of Appetite
- Behavioural Changes
- Pale Gums due to Anaemia
- Yellowing of gums, skin, whites of eye, due to jaundice
- Reduced Coordination
- Change in bowel movements such as diarrhoea, tarry stools or blood in stools
- Excessive Thirst
- Excessive Urination
- Skin changes such as scabs, redness or scratching
A consumer group ran a campaign called BARKS - "Be Aware of Rimadyl Known Side Effects".
Metacam (Meloxicam) under scrutiny
Metacam is another Non-Steroidal Anti-Inflammatory Drug (NSAID's) which is also prescribed for relieving the inflammation and pain associated with arthritis and other bone and joint problems which dogs can suffer from.
Metacam is marketed by Boehringer Ingelheim, a company that was founded in 1817 by Christian Friedrich Boehringer in Stuttgart Germany.
Boehringer manufactured chemicals such as tartaric acid salts that were much in demand for making fizzy lemonade. By 1955 the company established an Animal Health Division and by 2003 their animal health sales grew to 318 million euros. In July 2003 Boehringer Ingelheim launched its NSAID, Metacam in partnership with Merial owned by Merck and Co who produced the flea product Frontline and the heartworm preventative, Heartguard.
Like other NSAID's, Metacam is prescribed to relieve pain and inflammation associated with osteoarthritis and other bone or joint problems, pain associated with wounds and fractures and for pain relief following surgical procedures such as neutering and dentistry. Metacam works much the same as Rimadyl by inhibiting prostaglandin synthesis thereby exerting anti inflammatory, analgesic and antipyretic effects.
Listed adverse effects are:
The most serious adverse effects associated with all NSAID's occur in the Gastro-intestinal tract such as ulceration and bleeding. All NSAID'S can cause liver damage in dogs.
- Loss of Appetite
- Blood in stools
- Dark, tarry stools
3,200 dogs had died or been euthanized and nearly 20,000 dogs had adverse effects within a few years of the emergence of NSAID's, though one must add that by then several million dogs in thousands of veterinary surgeries had been prescribed the drugs.
Caution should be taken when prescribing NSAIDs.
The drug companies still maintain that if prescribed correctly, laboratory tests have been carried out and the dog is carefully monitored their medicines are safe.
Novartis, maker of Deramaxx stated:
“Deramaxx has been safely and effectively used to treat more than 1 million dogs for canine osteoarthritis.”
Boehringer Ingelheim maker of Metacam said that they were:
“Confident that there are millions of animals whose lives have improved by the pain-relieving benefits of Metacam.”
Any owner being prescribed one of the NSAID's for their dog should always ask for a client information sheet explaining the possible side effects of the drug and what to look out for. These are not automatically handed out by vets who buy shipments of the drugs from pharmaceutical companies then repackage them in smaller quantities for the client. In the process, the information sheets may be lost and the vet often does not clearly communicate the importance of monitoring the dog for adverse effects.
Before prescribing NSAID's the vet should carry out appropriate tests to establish blood values. These tests are expensive and not all dogs are covered by insurance. Often owners refuse testing being carried out as they struggle to pay veterinary bills. While the dog is taking NSAID's the animal should be closely monitored. Owners should be aware that even what seems a minor side effect such as lethargy can quickly progress into an emergency scenario.
NSAID's should not be combined with other steroids like dexamethazone, prednisolone, or depomedrol as gastro-intestinal ulceration and bleeding can result. These drugs should also never be given to any dog with impaired gastro-intestinal, kidney, cardiovascular, or coagulation problems.
More information on the adverse effects of NSAID's can be viewed at: www.dogsadversereactions.com/nsaid/comparison.html
Michele Sharkey, DVM says:
"The side effects of NSAID's are very well known and very well documented but this information is not always getting to the pet owners. If the pet owner can recognise a possible reaction, stop the medication and get veterinary help, it could mean the difference between a good outcome and a disaster.”
Stephen Sundlof, DVM, PhD, director of the Centre for Veterinary Medicine (CVM) says:
“These are valuable drugs that help many pets to live to a ripe old age”.
Millions of dogs have benefited by taking NSAID's worldwide and on the whole these drugs give excellent pain relief for many arthritic dogs. With adequate pre-screening, intensive monitoring and improved communication between the veterinarian and the client adverse reactions to these drugs could be reduced.
Linda Baker, of "Adopting A Dog" said:
“Adverse drug reactions in dogs is still a little known, misunderstood topic which needs much more public education.”
Any drug that dog owners give to their pets can have serious side effects and as owners we have the right to know as much as possible about any veterinary medication that we give our dogs just as we have the right to know about medicines we take ourselves.
The kindest thing we believe you can do for your dog is to feed it a natural, home-prepared diet, make sure your dog has plenty of fresh air, exercise and love, and to steer well clear of prescription drugs as much as possible.
Remember Jean Townsend who brought a class action lawsuit against Pfizer?
She sought reimbursement of $734.00 veterinary costs as well as acting on behalf of the hundreds of other dog owners whose pets had died. On August 18th 2004 it was announced that a settlement had been reached with Pfizer, the makers of Rimadyl, and as part of that settlement Pfizer had made cash offers to hundreds of other dog owners across the country averaging at over $1000 per animal. The offers did not include a confidentiality provision.
Details of the lawsuit can be viewed at:
This information is solely for the purpose of informing and educating the reader. If your dog is unwell, you should seek veterinary advice and do your own research on any prescribed drugs. Always ask for a client information sheet and be sure to monitor your dog for signs of adverse reactions. Should your dog displays any of the symptoms mentioned on the information sheet, however mild they may be, contact your vet immediately.
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