folic acid (folate, vitamin B9, FA-8, Folacin, Folic Acid, GNC Folic Acid 400, and many more)

  • Pharmacy Author:
    Omudhome Ogbru, PharmD

    Dr. Ogbru received his Doctorate in Pharmacy from the University of the Pacific School of Pharmacy in 1995. He completed a Pharmacy Practice Residency at the University of Arizona/University Medical Center in 1996. He was a Professor of Pharmacy Practice and a Regional Clerkship Coordinator for the University of the Pacific School of Pharmacy from 1996-99.

  • Medical and Pharmacy Editor: Jay W. Marks, MD
    Jay W. Marks, MD

    Jay W. Marks, MD

    Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.

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  • Preservative free oral capsules: 5 and 20 mg
  • Solution for injection: 5 mg/ml (10 ml)
  • Oral tablets: 400 mcg, 800 mcg, 1 mg
  • Preservative free oral tablets: 800 mcg dye free, 400 and 800 mcg

STORAGE: Folic acid preparations should be stored at room temperature between 15 C and 30 C (59 F and 86 F).


For the treatment of folate deficiency megaloblastic anemia or macrocytic anemia

Patients ≥ 11 years: Administer 1 mg by mouth, subcutaneously (into the fatty tissue), or intramuscularly (into the muscle) once daily until a satisfactory clinical response is attained. The maintenance dose for most adults and children is 0.4 mg by mouth once daily. Patients who become pregnant while undergoing treatment of megaloblastic anemia should receive a maintenance dose of 0.8-1 mg by mouth once daily throughout pregnancy and while breastfeeding.

Patients 1-10 years: Administer 1 mg by mouth, subcutaneously, or intramuscularly, followed by a maintenance dose of 0.1-0.4 mg by mouth once daily.

Infants: Administer 15 mcg/kg or 50 mcg by mouth, subcutaneously, or intramuscularly once daily.


Coadministration of folic acid with cholestyramine (Prevalite, Questran, Questran Light) may decrease the absorption of folic acid. Patients taking both medications are advised to take folic acid 1 hour before or 4-6 hours after cholestyramine.

Folic acid may interfere with methotrexate (Trexall, Rhuematrex, MTX), a medication used to treat certain cancers. Methotrexate works by decreasing the effects of folic acid and therefore, taking these medications together may decrease the effectiveness of methotrexate.

Folic acid supplements may reduce blood levels of certain anti-seizure medications including phenytoin (Dilantin), fosphenytoin (Cerebyx), primidone (Mysoline) and phenobarbital (Luminal) thereby reducing their effectiveness. Also, these medications may also reduce the blood levels of folic acid.

Medically Reviewed by a Doctor on 7/8/2015

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