For those of you that are interested, I did some research on Cimetidine quite a while ago and Tai has been on it ever since (600mg daily). I was fortunate in that her onco vet was familiar with some promising equine melanoma studies involving Cimetidine use and was willing to provide a prescription. Unfortunately in Canada, Tagamet (aka Cimetidine) is not available over the counter, although the same family of H2 inhibitors (Famitidine, Ranitidine (Zantac)) are. The cancer benefit is only found with Cimetidine. The following is an excerpt from the website http://www.topi…..alinfo.org, it lists numerous studies that have amazing results showing reduction or compete elimination of malignant tumors in colorectal, melanoma, and lung cancers.

"Cimetidine is an over-the-counter,
acid-blocking drug originally developed to treat heartburn, upset
stomach, ulcers, and gastroesophageal reflux disease. Used in
conjunction with other cancer therapies, cimetidine has been found to
significantly enhance cancer survival rates. Cimetidine works through
several mechanisms of action, preventing immune suppression caused by
tumor secretion of histamine, halting cancer growth, preventing
angiogenesis, promoting cancer cell death, and averting often-fatal
cancer metastasis.The May 2007 Life Extension Foundation
magazine has an article at http://www.lef……ine_01.htm
that says cimetidine is especially effective as an adjuvant cancer
remedy with surgery to stop the spread of cancers. During surgery, some
cancer cells may be released into the bloodstream. A suppressed immune
system may contribute to the ability of these residual cancer cells to
escape immune surveillance and establish metastatic lesions.
Cimetidine’s ability to reverse immune suppression could thus help the
immune system to remain alert to challenges such as spreading cancer
cells.
As an example of its effectiveness, in a 1994 study, just
seven days of cimetidine treatment (400 mg twice daily for five days
preoperative and intravenously for two days post-operative) in
colorectal cancer patients decreased their three-year mortality rate
from 41% to 7%".

As many of you have your dogs on Pepcid AC for stomach irritation you may want to consider asking your vet about switching to Tagamet and enjoying the potential benefit of Cimetidine as an anti-cancer drug.

Here is a further excerpt along with the medical references for those of you who like to look things up.

Cimetidine is probably the easiest drug
to obtain and is suggested as the drug of first choice when cancer is
suspected. The recommended dose is 1,000 mg per day.

References

1.
Armitage J O, Sidner R D. Antitumour effect of cimetidine? Lancet 1979;
i: 882-3.

2. Osband M E, et al. Successful tumour immunotherapy
with cimetidine in mice. Lancet 1981; i: 636-38.

3. Gifford R R
M, Fergusson R M, Voss B V. Cimetidine reduction of tumour formation in
mice. Lancet 1981; i: 638-40.

4. Thornes R D, Lynch G, Sheehan M
V. Cimetidine and coumarin therapy of melanoma. Lancet 1982; ii: 328.

5.
Borgström S, et al. Human leukocyte interferon and cimetidine for
metastatic melanoma. N Eng J Med 1982; 307: 1080-81.

6. Thornes R
D, Lynch G. Combination of cimetidine with other drugs for treatment of
cancer. N Eng J Med 1983; 308: 591.

7. Burtin C, et al.
Combination of cimetidine with other drugs for treatment of cancer. N
Eng J Med 1983; 308: 591-2.

8. Strauchen J A, Moran C, Goldsmith
M, Greenberg M. Spontaneous regression of gastric lymphoma. Cancer .
1987; 60: 1872-5

9. Tonnesen H, et al. Effect of cimetidine on
survival after gastric cancer. Lancet 1988; 2: 990-2.

10. Adams
W, Morris D L. Short-course cimetidine and survival with colorectal
cancer. Lancet 1994; 344: 1768-9.

11. Matsumoto S. Cimetidine and
survival with colorectal cancer. Lancet 1995; 346: 115.

12.
Adams W J, Morris D L. Pilot study cimetidine enhances lymphocyte
infiltration of human colorectal carcinoma: results of a small
randomized control trial. Cancer 1997; 80: 15-21.

BTW:  Just about any horse vet would confirm this.  It's pretty common nowadays.  So, if anyone wants to ask their dog oncologist, they could probably just check with their local equine vet and have them discuss it.  :)