mpbser wrote:For those people who are taking or who have taken cimetidine, here are a few sub-questions:
1. If you have stopped, how long did you take it for? Why did you stop? What was your daily dosage?
2. If you haven't stopped, what is your daily dosage? Are you aware of any issues with long term use?
I've always broken the "how long" decision into two periods, "perioperative" - say, a month before to a month after surgery, and "long term", out to a year or more. The cimetidine stats for surgery are so favorable, and so little personal information is available this early, that the general LEF recommendation is for everybody to do 800-1000 mg, maybe 1600 mg, where about half of men may not tolerate 1600 mg well long term. Females do better.
My wife, who has the bad biomarkers, took cimetidine for 6 straight years, often at 1600 mg but this is likely too high for most guys. She's been irregular on a lot of non chemo items this past year.
Given the Matsumoto(2002) paper on metronomic oral 5FU and cimetidine's effectiveness based on CA19-9 and CSLEX tissue stains, I insisted on CA19-9 serum levels before and after surgery. It seems clear that stage II and III patients with tumor tissues marked by CA199 and CSLEX1 antibody stains, in that era were totally screwed if they did not have cimetidine as well as
their daily oral chemo. Heavily double biomarker positive stage II and III patients might as well have been early stage IV due to their poor OS. The Matsumoto(2002) paper's OS of double positive CRC stg 2-3 patients appears better than Folfox if taken at face value. It is a small study well done. By the same token, stage 2-3 CRC patients without one or both of these markers may have done a little worse with the cimetidine. CA19-9 covers most of the biomarker based risk, where CSLEX or bioequivalent CD15s antibodies are usually unavailable. Pathologists seem reluctant to do nonstandard staining, so pretreatment serum CA199 is the first, easiest step.
Long term use is going to reduce digestive capacity without digestive support (betaine HCl and/or pancreatic enzyme supplements). Cimetidine may be a slight OS drag on the minority of pts negative for one of or both of the tissue markers, CA199 and CSLEX1.