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Cimitidine and Fluorouracil (5-FU)


I felt I should post this ... I had read somewhere that there may be an adverse interacton with taking Cimitidine and Irinitican ... according to this information it is the Fluorouracil which is also part of FOLFOX.  



May be worth checking with Pharmacist rather than Oncologist




  • annalexandria
    annalexandria Member Posts: 2,571
    Interesting, thanks for sharing...

    I know a lot of people are taking cimetidine on a regular basis, but I was told that it could be problematic if you don't need the antacid effect.  I do think it's still worth taking for a few weeks before and after surgery...less chance of unwanted interactions that way.

  • tanstaafl
    tanstaafl Member Posts: 1,299
    who knows is always a challenge

    For most people, cimetidine has been fine with 5FU and its derivatives. As with most chemotherapy, dose adjustments might be necessary.  I would be a little more cautious about direct combination on FOLFIRI days with cimetidine, not a lot of experience on the board, and some -iri-table days were noted.  Inhibiting 5FU metabolism  can mean improved performance, depending on the pathways involved.

    In real life, I haven't run across any pharmacists that knew anything about cimetidine for colon cancer. At our house, daily cimetidine and 5FU (as DPD inhibited tegafur/uracil) have been important parts of my wife's chemo for over 5 years. In the papers' statistics, cimetidine appears to help a majority of advanced crc patient (stage III and IV) and the stage IIs that would/did recur.  This has to do with the metastatic nature of those with peak CEA and CA19-9 values that are not too low, both values ever elevated, and probably most KRAS mutants.