maximum dose of folic acid
Started by shahj3
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What underlying disorders does the patient have? What else is the patient on?
This is one of those instances where I would get as much information as possible from the patient...see what else the patient is on (any methotrexate?) and ask the patient what the doctor told her. Ask about other vitamin usage. I'd be concerned about folate masking vitb12 deficiency at those doses so I'd ask about other vitamins too.
Then armed with that information, call the physician to be sure.
This is one of those instances where I would get as much information as possible from the patient...see what else the patient is on (any methotrexate?) and ask the patient what the doctor told her. Ask about other vitamin usage. I'd be concerned about folate masking vitb12 deficiency at those doses so I'd ask about other vitamins too.
Then armed with that information, call the physician to be sure.
I wouldn't consider age 50 to 60 elderly. But that is a high dose. It's usually 1 mg/day. Did you mean 2000 mg or 2000 MCG?
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Wow I'm terrible. I read it as mcg. Good catch.
2000 mg or 2000 mcg is still a high dose!
Although I think it is used at doses that high (or higher) in pregnant females with family history of or prior pregnancy with a neural tube defect.
But not for a middle aged dude, as far as I know.
But not for a middle aged dude, as far as I know.
Yeah, on the high end definitely. I've seen it for pregnant women who couldn't be transitioned off their anticonvulsants and those doses can go up to 4mg/day.
I was thinking methotrexate use for RA.
I certainly hope you pause for a second and wonder "WTF am I doing?" before you tell the patient to take 2,000 1 mg tablets by mouth daily or inject 400 mL of 5 mg/mL solution.
Assuming you meant 2,000 mcg, that's ok. The acceptable uses of such a high dose include:
- prevention of methotrexate toxicity in RA
- prevention of neural tube defects in pregnant women with a history of them, but your pt is too old to be pregnant
yes, 2 g of folic acid daily is a very high dose - and, as pezdispenser points out, very impractical.
How are you making a 1mg dose up from available OTC formulations? The 1 mg tablet is RX only.
The real world answer is:
Who cares, they'll pee all the excess out anyway.
Who cares, they'll pee all the excess out anyway.
Working with pediatric leukemia patients, Sidney Farber first gave folic acid. After he noticed it made the cancer more aggressive, he concluded he needed an anti-folate. Of my own curiosity and failure to find early data, does anyone know how much folic acid he was giving these original patients?
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Correct. 4-5 mg qday for high risk pregnancy which include anticonvulsant and hx of defect.
Farber and colleagues performed dose ranging studies of folic acid (pteroyglutamic acid) from 10 mg to 500 mg daily via several routes (IM, IV, PO) to 90 patients without reports of toxicity. They subsequently recommended dosages of 20-50 mg/day intramuscularly.
Farber et. al. "The action of pteroyglutamic conjugates on man." Science 1946.
Good luck finding that one...
You are the best, I am going to have a friend print off the article if it can be found 🙂. Because I am in my "in between" year of graduating university and starting pharmacy school my journal access has been cut off :-(
Because the OP said 2000mg of folic acid (even though he/she meant micrograms) I thought to myself "wow, that must be a Farber dose!"
I've seen doses up to 5 mg/daily used for certain hyper coagulable states (I believe they are associated with elevated amounts of homocysteine). I'm too lazy, tired, and sick right now to research it though.
2000 mg is obviously a typo. On the flip side I wouldn't even think twice about 2000 mcg daily.
2000 mg is obviously a typo. On the flip side I wouldn't even think twice about 2000 mcg daily.
Homozygous MTHFR mutation is what you're referring to....however usually they give more reduced forms of folic avid as conversion is the primary issue
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A doc was trying to use that possibility to justify why his patient needs non formulary Deplin. I did some poking around and found that it's only 60% reduction with that mutation, so i asked him why not just up the dose of folic acid to compensate? Anyway, he didn't challenge that, probably knew Deplin for treatment of depression is a bit dodgy.
Off topic but I love the ballsy-ness of leukovorin rescue therapy. We are going to give you enough MTX to kill a horse but don't worry. We have the antidote ready to go!!
haha. I see leucovorin quite a bit and I agree...crazy what they put in people.
On my list of crazy is undiluted etoposide being infused into someone. The fact we have to use special bags/tubing because the drug eats through plastic is scary. 😱
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