Overview
DESCRIPTION Folic acid, N-[ p -[[(2-amino-4- hydroxy-6-pteridinyl) methyl]- amino] benzoyl]-Lglutamic acid, is a B complex vitamin containing a pteridine moiety linked by a methylene bridge to para -aminobenzoic acid, which is joined by a peptide linkage to glutamic acid. Conjugates of folic acid are present in a wide variety of foods, particularly liver, kidneys, yeast, and leafy green...
Mechanism of Action
CLINICAL PHARMACOLOGY Folic acid acts on megaloblastic bone marrow to produce a normoblastic marrow. In man, an exogenous source of folate is required for nucleoprotein synthesis and the maintenance of normal erythropoiesis. Folic acid is the precursor of tetrahydrofolic acid, which is involved as a cofactor for transformylation reactions in the biosynthesis of purines and thymidylates of nucleic acids. Impairment of thymidylate synthesis in patients with folic acid deficiency is thought to account for the defective deoxyribonucleic acid (DNA) synthesis that leads to megaloblast formation and megaloblastic and macrocytic anemias. Folic acid is absorbed rapidly from the small intestine, primarily from the proximal portion.
Indications
- INDICATIONS AND USAGE Folic acid is effective in the treatment of megaloblastic anemias due to a deficiency of folic acid (as may be seen in tropical or nontropical sprue) and in anemias of nutritional origin, pregnancy, infancy, or childhood.
Common Doses
- 0.1 mg
- 1 mg
- 0.3 mg
- 0.4 mg
Dosage
DOSAGE AND ADMINISTRATION Oral administration is preferred. Although most patients with malabsorption cannot absorb food folates, they are able to absorb folic acid given orally. Parenteral administration is not advocated but may be necessary in some individuals (e.g., patients receiving parenteral or enteral alimentation). Doses greater than 0.1 mg should not be used unless anemia due to vitamin B 12 deficiency has been ruled out or is being adequately treated with a cobalamin.
Contraindications
- CONTRAINDICATIONS Folic acid is contraindicated in patients who have shown previous intolerance to the drug.
Side Effects
- ADVERSE REACTIONS Allergic sensitization has been reported following both oral and parenteral administration of folic acid. Folic acid is relatively nontoxic in man. Rare instances of allergic responses to folic acid preparations have been reported and have included erythema, skin rash, itching, general malaise, and respiratory difficulty due to bronchospasm. One patient experienced symptoms suggesting anaphylaxis following injection of the drug.
Interactions
- No major interactions listed on the FDA label. Always consult a healthcare professional.