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Featuring Demian Dressler, DVM and Susan Ettinger, DVM, Dip. ACVIM (Oncology), authors of The Dog Cancer Survival Guide

Bone Tumors and Doxcycline

Updated: October 9th, 2018

Osteosarcoma, and other types of canine bone cancer, can be especially hard for a dog lover to cope with.  Not only are most of these cancers very malignant, but often they require major surgeries to help deal with the immediate crisis.

Once the decision is made and the surgery performed, we are faced with cancer spread (metastasis).  One reason  this is tricky is osteosarcoma often will send out microscopic tumor cells into the circulation by the time the diagnosis is made.

This can be devastating for a dog lover.

In The Dog Cancer Survival Guide, many ways of addressing cancer spread are discussed. Let’s look at the use of a common prescription medication available from veterinarians: doxycycline.

Doxycycline is known as an antibiotic since it can destroy certain microbes. However, there is new research on some of it’s cancer-fighting properties.

One of the nice things this medication can do, at least in labs, is block enzymes that seems to be very important in cancer spread.  These are called matrix metalloproteinases, or MMP’s.

MMP’s are kind of like pac-men, from the old video game.  These enzymes are secreted by the cancer cells into the surrounding neighborhood, and they start gobbling.  They literally break down protein in the tissue around the cancer cells, leaving tunnels or holes.

The channels made by the MMP’s allow the cancer cells to take off into the surrounding neighborhood, and spread.  Cancer cell spread is central in the harm they cause the body.

In mice with experimental cancer that had spread into the bone, it was found that doxycyline was able to block cancer cells invading into bone by about 70%.

Now, don’t get me wrong. I am not saying that this medication is the cure for cancer.  A full plan must be implemented to get a real edge.

In dogs under my care, I advocate focus on diet, designed supplements, conventional care, stress and isolation reduction, vaccine avoidance,  photoperiod regulation, timed therapy,  pain control and more.

By using all of these together, many dog lovers report tremendous gains in their four legged friends.


Dr D

Discover the Full Spectrum Approach to Dog Cancer

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  1. Dr. Demian Dressler on March 19, 2013 at 4:29 pm

    Well Elaine…if its working, it seems like the best option is to continue. The doxycyline issue is a pain right now, but searching around can still yield some reasonable prices.
    Dr D

  2. Elaine on March 19, 2013 at 9:02 am

    Just curious if you have any advice for us regarding Newman (see above). Sounds like its going to be harder (and more costly) to get doxycycline. Thoughts?

  3. Elaine on January 2, 2013 at 4:06 pm

    Well! We took Newman to UC Davis for a CT scan to see if he qualified for their cryoablation clinical trial. Guess what?! There’s no tumor! It’s nowhere to be found–for now at least! So we are calling Newman our Christmas miracle. Still doing supplements and doxycycline. Obviously too afraid to take him off, since his regime seems to be working–for now at least! Thanks for all your help!

  4. Elaine on November 20, 2012 at 7:05 am

    Dear Dr. Dressler,
    Our Weim, Newman, has broken the odds and is still with us after 11+ months from removal and diagnosis of his nasal tumor (yes, that was the order in which things happened, as none of the tests revealed cancer until the mass was sent to pathology). All this time Newman has been on the recommended dose of doxycycline–2 weeks on then 2 weeks off. We know the tumor is invading again, as we now know what tell-“tail” signs for which to look. We do not wish to go through radiation treatments; however, Newman might be a candidate for a new clinical trial at UC Davis–cryoablation. Your thoughts on that form of treatment?

  5. Elaine on January 4, 2012 at 5:37 am

    Question on dosage of doxycycline. As per your recommendation in your book, our 90-pound Weimaraner should receive 225 mg per day. Should this be broken up into 2-100ish mg doses every 12 hours? Or can/should the 225 mg be done in one fell swoop? Thanks!!

  6. Elaine on December 31, 2011 at 7:06 am

    Question on dosage of doxycycline. As per your recommendation in your book, our 90-pound Weimaraner should receive 225 mg per day. Should this be broken up into 2-100ish mg doses every 12 hours? Or can/should the 225 mg be done in one fell swoop? Thanks!!

    • Dr. Demian Dressler on January 4, 2012 at 5:04 pm

      Dear Elaine
      we usually give this medication once daily under veterinary supervision. Please be sure to touch base with your vet before any changes are made.
      Dr D

  7. Carly on May 25, 2011 at 5:17 pm

    Dr. D
    Why is there red and blue dye in your Apocaps?
    I thought dyes were bad for you.

    • DemianDressler on May 25, 2011 at 8:53 pm

      Dear Carly,
      The colors are food colors and are not harmful. The ones used in the formula were carefully screened for safety. They are simply there for aesthetics (looks). However, due to the concern in the general public (which was justified when certain dyes were found to be harmful in the past, but not these new food colors), we are getting the next batch done without colors. As a matter of fact, I was just working on the label formatting this evening. Should be available in about 3-4 months, maybe sooner.

  8. Nicole on May 4, 2010 at 2:28 pm

    Any concern about using Doxycycline when no infection exists. Would there be resistance to it when they really need an antibiotic?

    My girl was on Doxycycline for 6-months as part of Metronomic Protocol. She had no problems with it; however, I’ve heard this concern expressed many times so … I thougth I’d ask. Thank you!

    • Dr. Dressler on May 16, 2010 at 11:43 am

      Dear Nicole,
      like many areas of medicine this is a risk-benefit choice. Although we do have resistant germs to consider, if your dog is benefiting I usually will pick the choice in the direction the scale tips, if you catch my drift.
      Dr D

  9. Kay on May 4, 2010 at 7:13 am

    Dr. Dressler,
    In this blog you say that you advocate vaccine avoidance. What is your stance on using heartworm preventative and/or flea/tick preventatives on dogs that already have cancer? Are there any products that you would definitely avoid or products that you think are safe?


  10. Judith Conigliaro on May 4, 2010 at 5:09 am

    Dr. Dressler,

    My dog Abigail has bladder cancer. She is on doxycycline as part of her treatment, together with 2mg of Piroxicam, Artemin and Dr. Andrews’ Supplement Powder. I took part in the webinar that you held with James Jacobson back in March. James read two of my questions during that webinar and you answered both of them. At the time of her last ultrasound, the tumor was found to have shrunk down the point where my vet had to “look” for it. Happy news for me and Abby. Even my vet was a bit surprised! My vet downloaded the information on Apocaps as I donated some money for your resarch. Your thoughts on starting Apocaps?

    • Dr. Dressler on May 16, 2010 at 11:47 am

      Dear Judith,
      I am so pleased to hear this good news!
      Well, as far as Apocaps is concerned, I use this formula for my own patients frequently. I am unable to make specific medical claims on this website however. I would team up with your vet on this. I would also use a half dose of Apocaps with the other supplements you mention.
      Great work,
      Dr D

  11. Scott M on May 4, 2010 at 4:57 am

    Interesting article…

    How have you addressed the nausea that comes with this drug? It seems to b e the most common side effect.

    My wife and I have elected not to pursue amputation (right front leg) with our dog because she has three other bad legs and is 11-years old. The left front leg has elbow displasia and the rear legs have had past ACL surgeries. She is on Trimidol, Proxicam, and as suppliments takes K9 Immunity, Glucosamine, fish oil and eats a grain free diet.

    We are going to talk to our general vet about Pamidronate, a bisphosphonate to delay local bone destruction and are researching other options. However, it’s difficult because our general vet isn’t very knowlegeable in this area and when we were referred to specialists, surgery centers and oncologists, all they want to do is amputate, radiate and chemo and seemed to indicate all other options are not worth while to pursue.

    • Dr. Dressler on May 16, 2010 at 11:55 am

      Dear Scott,
      Nausea can be seen, to be sure. If a dog has an intolerance to any medication or supplement this can be the end result. Has it occurred with your dog?
      Nausea can be addressed with famotidine (pepcid), dosing with a full meal, ginger, metoclopramide, slippery elm, remeron, and cerenia, to name a few strategies.
      Have you looked into Apocaps? I cannot make any specific claims on this website but suffice it to say I would team up with your vet and consider it. I would advise it at half strength with the Piroxicam. I am sure your vet can handle the pamidronate with a little focus.
      Have you read the Guide? This is such a large area that it would be a good idea since you are being a great example of an your dog’s advocate!
      Dr D

  12. Darcy on May 4, 2010 at 3:39 am

    I have had my Vizsla on doxycycline since he finished chemo in 2008, and after a full scapulectomy, and we are celebrating his 2 year Ampuversary in June.

    • Dr. Dressler on May 16, 2010 at 11:55 am

      Dear Darcy
      Congratulations!! Great work.
      Dr D

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