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Methotrexate

May 24, 2009

We’ve had this one since the beginning, but I’d like to highlight it a little this month, because it is her first time getting it through her port.

MTX as it is known, invented in Boston in the 1940’s became an approved drug for chemotherapy by the FDA in the 1950’s.  Whee, it was discovered by a doctor who was researching what role folate played in blood cancers. Who knew that cancer research started so long ago? Never-the-less, instead of using folate, MTX is ANTI-folate.  Sort of like an antidote to poison. 

To describe how it works is tough. Imagine having only one seat left in a packed auditorium that is supposed to be for Folate. Both MTX and Folic Acid want that seat. Too bad for ole folate because MTX has an incredible ability to get to that seat before Folate even knows it is there.  Once MTX is there, nothing else seems to work.  Because MTX takes the place and stops mechanisms thats folate usually helps.

We were told in the hospital not to give Isa vitamins with folate in them. Nearly every vitamin has them, except a few, usually for infants. My guess is because the formula usually has it in it. What are nursing mothers to do?  When I specifically asked Dr. H. about Isa’s intake of folate he said, that what found in the food is not likely to cause a problem, but that vitamin supplements could cause a problem. He postulated that the larger dose often found in vitamins might make a difference.  So, no vitamin with folate. 

As with a lot of chemo drugs, this one works on the fast acting cells, like hair and intestines. So, hair loss is common perhaps especially when given by IV, mouth or in the muscle, considering the spinal fluid doesn’t usually interact with those tissues. 

Penicilin should not be taken while on MTX. Interestingly, some things like antibiotics can reduce the absorption of MTX, especially, vancomycin, neomycin, and bacitracin.  One sight stated that BACTRIM or SEPTRA should not be given within 24 hours of MTX because the MTX would be intensified. Remember folks, Isa gets Septra every week as a preventative to getting Pneumocystis Carnii which is actually called something different now.  Also oddly enough, Vitamin C increases the toxicity as well. Also avoid NSAIDS, which most leukemia kids will only be taking tylenol anyway. The others, ibuprofen, aspirin and such thin the blood, and with low platelets, why thin the blood anymore.

This drug is really gnarly for babies. (How long has it been since you heard that word? I learned it from the Valley Girl Dictionary I had in high school.)  So if you are pregnant or breast feeding or if you  are a dude who wants some babies. Skip this one. 

Some kids have very severe side effects of this medicine, like stroke. Some have rashes and intense vomiting with or without extremely bad mouth sores that lead to feeding through a tube.  Some have very little. Before, Isa got this medication she got some Zofran to limit her nausea.

Each week in maintenance the dosage increases on this drug. Therefore EVERY week in Augmented Interim Maintenance is COUNT dependent. To receive any treatment she must be 750 ANC and 75,000 platlets. BUT if her numbers are low, then the MTX will NOT be increased. From what I understand it would stay the same as the last dose. BUT I could be wrong on how that works.

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One Comment leave one →
  1. August 26, 2014 3:44 pm

    Mtx also often causes leukoencephalopathy which is what happened to my little one. As a result she experienced seizures and is now on seizure meds.

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