Cimetidine use

laurettas

tanstaafl said:

Any -iri experiences anyone?
No cimetidine -iri experience here, used it in 5FU super-maintenance mode only.

The Japanese research shows cimetidine and UFT used in steady daily doses, bid and tid respectively, rather than weekly or monthly boluses. Lisa42 has mentioned cimetidine during the months of her 5FU/xeloda-gemcitabine (Gemzar) treatment, might be a good idea to clarify her experiences.

Thank you
Many thanks for all of the responses. Our doctor has OK'ed the use of Tagamet, just want to check on its compatibility with Lovenox and get any supplements we may need to offset the lack of acid in the stomach.

Also, tanstaafl would it be helpful at this point, after six months of chemo, to get the markers checked that you mentioned? His CEA was down to 6 a month ago so don't know if the other markers would still be elevated at this point.

tanstaafl

laurettas said:

Thank you
Many thanks for all of the responses. Our doctor has OK'ed the use of Tagamet, just want to check on its compatibility with Lovenox and get any supplements we may need to offset the lack of acid in the stomach.

Also, tanstaafl would it be helpful at this point, after six months of chemo, to get the markers checked that you mentioned? His CEA was down to 6 a month ago so don't know if the other markers would still be elevated at this point.

biomarkers
We get my wife's blood and markers checked 1-2x per month, depending on how much is going on.

Biomarkers like CA19-9 for molecular targets work best if you have the (pre-)surgery value. The best way to get a biomarker is to have the pathology sample from surgery made into slides, stained and measured for overexpression. We've recently gotten the stains done for CA19-9 (cimetidine), CSLEX (cimetidine) and COX2 (celecoxib).

smokeyjoe

laurettas said:

Thank you
Many thanks for all of the responses. Our doctor has OK'ed the use of Tagamet, just want to check on its compatibility with Lovenox and get any supplements we may need to offset the lack of acid in the stomach.

Also, tanstaafl would it be helpful at this point, after six months of chemo, to get the markers checked that you mentioned? His CEA was down to 6 a month ago so don't know if the other markers would still be elevated at this point.

I'm on Lovenox, prescribed
I'm on Lovenox, prescribed by my onc. and he approved the cimetidine....so I'm assuming there's no problem....but ask your onc. in any event.

laurettas

smokeyjoe said:

I'm on Lovenox, prescribed
I'm on Lovenox, prescribed by my onc. and he approved the cimetidine....so I'm assuming there's no problem....but ask your onc. in any event.

Thanks again
I will ask Jake's onc if we can get those markers from his tumor analyzed next time we see him. We mentioned the cimetidine to his onc and he prescribed the Lovenox so hopefully he remembered about both drugs when he OKed him taking cimetidine!

I was reading about 5FU and saw this:

What Do I Need to Know Before Starting 5FU+Leucovorin?

5-FU can cause heart problems such as a heart attack, irregular heart beat, angina and heart failure. This side effect may be more common in patients with a history of heart disease. Call your healthcare provider immediately if you have back pain, flushing or chest tightness.

Your treatment can interact with other medicines, including:

* Warfarin (Coumadin®)
* Cimetidine (Tagamet®)

on this site:

https://www.navigatingcancer.com/chemotherapy_treatments/5fu-lv-colorectal

Any thoughts on cimetidine interacting with 5FU?

tanstaafl

laurettas said:

Thanks again
I will ask Jake's onc if we can get those markers from his tumor analyzed next time we see him. We mentioned the cimetidine to his onc and he prescribed the Lovenox so hopefully he remembered about both drugs when he OKed him taking cimetidine!

I was reading about 5FU and saw this:

What Do I Need to Know Before Starting 5FU+Leucovorin?

5-FU can cause heart problems such as a heart attack, irregular heart beat, angina and heart failure. This side effect may be more common in patients with a history of heart disease. Call your healthcare provider immediately if you have back pain, flushing or chest tightness.

Your treatment can interact with other medicines, including:

* Warfarin (Coumadin®)
* Cimetidine (Tagamet®)

on this site:

https://www.navigatingcancer.com/chemotherapy_treatments/5fu-lv-colorectal

Any thoughts on cimetidine interacting with 5FU?

5FU interaction
"Any thoughts on cimetidine interacting with 5FU"
Yes, when used daily (low dose UFT, non-US + cimetidine) they seem to stop my wife's metastases from certainly spreading, where the surgeons' 1st, 2nd and 3rd reflex are aggravated met concerns.

Long term use (several weeks) of cimetidine at 1000 mg/day has been shown to alter pharmcokinetics of 5FU, likely shifting the dosage effects of 5FU efficacy and toxicity, up, with some DPD inhibition (Textbook of Personalized Medicine). UFT is already DPD inhibited, a little more from cimetidine may not be as big a deal as with IV 5FU treatment.

DPD inhibition of 5FU degradation (making it "stronger") hasn't been too much of a concern because my wife UFT's (oral pro5FU) dosing schedule started out very low for nominal stage III, and her 5FU tolerability has been custom fit for (increased) dosage as data changed (folate toxicity, stage IV, leucovorin availability, various ameliorating tx: eg. PSK, vit C, glutamine, etc).

We keep track of INR loosely - no port, no clots, no heparin, no active disease evident (suspicious lung nodules, inactive on April PET, no CT size changes by Sept, 17 months). With a port, active disease and heparin, they may track INR, PTT more frequently. Cimetidine possibly has a faint interaction that may go into the overall titration of INR.

tanstaafl

tanstaafl said:

stage four-ever
She has been on cimetidine everyday, including surgery. With stage IV, an initially elevated CA19-9 (and still highish), and apparent granulocyte attack response, cimetidine is a high priority.

She takes digestive supplements to improve nutrient breakdown and absorption: L-glutamine for the GI epithelial lining; about two 10 grain betaine hydrochloride with pepsin to replace stomach acid, and several 1400 mg (equivalent) pancreatin.

She also takes number of high strength supplements including high dose vitamins except no vitamin A. Does some juicing. Lower carb diet, milk whey protein shakes with medium chain triglycerides and supplements. No synthetic folic acid, leucovorin (folinic acid) and natural source (reduced) folates to avoid 5FU toxicity.

clarify earlier Oct 28 comment on folates with 5FU meds
My wife takes no synthetic folic acid (like commercial bread, most commercial multivitamins and B-complex unless "active"/natural forms) because of synthetic folic acid's toxicity with 5FU as eventually demonstrated in her early experience. She uses lower dose leucovorin (carefully tracked) with her 5FU prodrug, and eats natural sources of folates like liver without known restrictions. We formulate her own daily B complex (B1,B2,B3,B5,B6,B7,B12) intake into her schedule and shakes to assiduously avoid synthetic folic acid.