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Previcox For Injured Dog

May 17th, 2008, 05:42 PM
I did something last Sunday that I'll feel guilty for forever. I am disabled and have problems with my balance. I tried to get to a chair that was beside my Pepper and fell on her. She yelped and continued yelping until I was able to get off of her. I was so afraid I had hurt her back. As it was late at night and other than lying fairly still on the carpet, I decided to wait until the next day to get hold of my vet. As I have done with every other dog I have had, I gave her 1 325mg ASA wrapped with cheese to help with any pain. She was able to walk but very stiffly and her back legs took very small steps.

I phoned the vet first thing on Monday and she told me to wait until Wednesday to bring her in, because I had given her ASA. She said that it had to be out of her system for 48 hours before she could medicate her with anything else.

Pepper was able to walk up and down 4 steps (she has to do that to get outside) and walk around the house, but again very stiffly. She didn't eat at all but would take the cheese that I gave her and some rollover I had in the fridge. She also would eat milkbone treats (the small bone size). I thought about her pain and didn't want to leave her with no pain meds for 48 hours when she was quite obviously in pain. So I continued to give her ASA - once every 12 hours. By Wednesday Pepper was moving better and did eat her dry food that had been sitting there for 2 days I talked to the vet and we decided that it would be very difficult for me to get her in the car when she was so stiff in the rear end so I was take her in on Friday with no ASA since Wednesday night. Each time I gave it to her she became more able to move around and seemed to have much less pain.

Thursday Pepper went and grabbed a pizza box that was in the recycling bin (she loves garbage) and hauled it into the house. This was my first sign that she was better and much less stiff so I finally realized that I couldn't possibly have done anything that would end up with her being put to sleep.(my big fear).

We saw my vet on Friday and she said there really wasn't much wrong other than Pepper was stiff and sore from being landed on....thank goodness!!
She suggested I start Previcox, 1/2 tab once a day for her pain, but that I might want to continue it forever after she's better if it worked well for any arthritis she had. I read all the literature I could find on it, googled it, and was very reluctant to start it. I finally decided to give her the first 1/2 tablet and see how she reacted to it at 7pm last night. She slept and slept and slept. She didn't move from where she was until 2am when she got up and turned around and lay down again. She had not been out to pee either. Finally at 4 am she woke me to let her out and she managed the stairs stiffly. This morning she moved from where she was sleeping 15 feet, had a long drink of cold water and went back to sleep. She went out to pee again at 3 pm and came in and went back to sleep. She wakens easily but is in no hurry to do anything or move anywhere.

When I gave her the ASA earlier in the week, before I gave it she was quiet and reluctant to move too far. After I gave her ASA she became more active, moving regularly to another place in the house, following me wherever I went, and smiling. She was still quite stiff, after the ASA but it was obvious it had helped with the pain and she was behaving more normally.

All this sleeping I suppose could be because she really hadn't slept well since I fell on her, but I don't like it at all. I really hesitate to continue it and with my vet away for the long weekend, I can't ask her opinion.

I would like to know if anyone has any experience with Previcox and whether they found their dog slept more than usual.

Dr Lee
May 17th, 2008, 08:44 PM
ASA (acetylsalicylic acid (aspirin)) is far less safe than Previcox (firocoxib) in my opinion for two reasons. First ASA has minimal COX-1 sparing properties and secondly it causes platelet dysfunction.

For those reading this, lets go back to these medications basics. Aspirin, Ibuprofen, Tylenol, Celebrex are common human anti-inflammatory and pain medications in a drug class called NSAIDs (Non Steroidal Anti Inflammatory Drugs). Common veterinary versions include: Rimadyl (carprofen), Metacam (meloxicam), Zubrin (tepoxalin), and Previcox (firocoxib). (There are many others in both human and veterinary medicine). They work by interacting with two receptors: Cox-1 and Cox-2 (there are other receptors but for simplicity, lets just talk about these two). Cox-2 is what we want to work with as it helps reduce inflammation and pain. Cox-1 is associated with internal functions of the body such as stomach mucous lining, stomach acid production and kidney blood flow.

Aspirin works with Cox-1 and Cox-2 nearly equally and with dogs having a higher ratio of Cox-1 to Cox-2 than people, the negative aspects of this medication are more prominent in dogs. There have been some studies that show that when you give normal aspirin doses to dogs who are without outward clinical signs - there is still decreased kidney blood flow and some degree of intestinal bleeding.

Many people will say, 'well my old vet always said aspirin was okay.' If aspirin was that safe and worked that well, then there would not be the large financial investment of research to find better, safer, more effective NSAIDs. Previcox was tested directly against Metacam, Deramaxx, and Rimadyl. The study showed Previcox as highest in safety with Metacam right behind it and Deramaxx at the bottom. It also showed all of them to be similar in pain relief at 48 hours and at 2 weeks of therapy. Previcox then showed greater pain relief than the others at one month of therapy.

The second problem is the platelet interaction. The dose of aspirin that is needed to cause platelet dysfunction and resulting increased bleeding potential is 1/20th to 1/50th the dose needed to relief pain. Therefore if you are having pain relief with the aspirin you are at least 20 times the dose needed to inhibit platelet aggregation in your dog!!!

Based on the test is Previcox the best? Well, the testers who were admittedly paid my the company that makes Previcox would like to think so. But really the answer is no. It is the best for some dogs. The reason that there are so many on the shelf is that not all dogs will positively respond to each NSAID the same. Just as some people like advil over aspirin or Tylenol over Advil etc... Some pets will like Rimadyl or Deramaxx over Metacam or Previcox. This is the reason for monitoring clinical improvement and repeat blood testing. If anyone still wants to use aspirin, or heaven forbid ketoprofen, then you should still have blood testing done on your pet. Any dog can have a negative reaction to any NSAID.

Why the dry out period of 48 hours? Well when you give an NSAID, while the pain relieving affects only last 12-24 hours, the Cox-1 effects can be present for two weeks. Also when you mix two NSAIDs, the ability of having complications can be as much as 20 times the risk as giving each individually. (If I remember, the number of nearly twenty times the risk of complications was based off of an aspirin and rimadyl study).

"My dog sleeps more after the NSAID". This can be difficult to interpret. On one hand, if a pet is in pain, it takes a lot of energy to deal with the pain. After giving a pain medication, many pets take advantage of the relief and sleep and recover. On the other hand, if there is a negative reaction to the medication, they may not be feeling well. This might be a need to recheck with your veterinarian to see what exactly is going on. I have a lot of clients that tell me that the NSAID makes their pet sleepy.

Again, no NSAID is perfect and individual results vary but I still maintain that Previcox, Metacam, Rimadyl, etc... deserve to be on the shelf as one of the frontline medications for pain. I also believe that other than dogs that need aspirin for its platelet effects (those that are predisposed to forming blood clots) that aspirin really needs to take a back seat.

Final thought. NSAIDs are not the only pain medication out there. If you use another class of pain medication, (again, I preach on multi-modality therapy) you can use it with or in lieu of an NSAID. Tramadol comes first to mind - it is safe, effective and inexpensive.

:sorry: for going on and on :pawprint:

May 17th, 2008, 09:50 PM
Thanks again Dr Lee, I appreciate the information it is vital for dog and cat lovers everywhere to know, to make an informed decision and not jump to the ASA as I did. I am not sure if you realized but I am the one who has posted about the Giant Lipoma and it seems to me that ASA is a really bad choice after reading what you wrote. I think I will hold the Previcox today and see how she is tomorrow and if I see her in pain I'll give it to her tomorrow. As she weighs 78 lbs (probably 8-10 lbs of lipoma) the dose of Previcox at 1/2 a tab is on the low side and can be given tomorrow safely. If she's still on the sleepy side tomorrow I'll wait until Tuesday when my vet is back in her office to talk about a change in medication. (its a long weekend here)