Folic acid Side Effects
Some side effects of folic acid may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.
For the Consumer
Applies to folic acid: oral tablet
Get emergency medical help if you have any of these signs of an allergic reaction while taking folic acid: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Less serious side effects are more likely, but may include:
nausea, loss of appetite;
bitter or unpleasant taste in your mouth;
feeling excited or irritable.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.
For Healthcare Professionals
Applies to folic acid: compounding powder, injectable solution, oral tablet
Gastrointestinal side effects have been reported rarely. They have included anorexia, nausea, abdominal distention, flatulence, and bitter taste.
Gastrointestinal side effects have been reported among patients with doses of 15 mg/day.
Nervous system side effects have included sleep disturbances, concentration problems, irritability, anxiety, depression, confusion, and impaired judgment.
Parenteral administration of high doses of folic acid have been associated with increased seizure activity in patients with epilepsy.
Nervous system side effects have been reported in some patients who were taking 15 mg/day.
Daily doses of folic acid > 100 mcg/day can obscure pernicious anemia in that hematologic remission can occur while neurologic signs and symptoms progress.
Hypersensitivity side effects have been reported rarely. They have included erythema, rash, pruritus, malaise, dyspnea with bronchospasm, and a single case of apparent anaphylaxis.
Metabolic side effects have included impaired gastrointestinal absorption of zinc.
A measurable decline in plasma zinc has been associated with folic acid dosages as low as 400 mcg/day.
Zinc is an intrinsic part of at least 70 metalloenzymes and other cellular components, and is essential for the synthesis of protein, DNA, and RNA. While zinc deficiency is rare, it may become a problem during pregnancy or with patients who have inflammatory bowel disease, malabsorption, liver cirrhosis, and high alcohol intake. Zinc deficiency usually presents as diarrhea; mental irritability; depression; skin lesions of the face, perineum, limbs, and skin folds; alopecia; loss of taste; and defects in the immunologic system.
More folic acid resources
- folic acid Concise Consumer Information (Cerner Multum)
- folic acid Oral, Injection Advanced Consumer (Micromedex) - Includes Dosage Information
- folic acid MedFacts Consumer Leaflet (Wolters Kluwer)
- Folic Acid Prescribing Information (FDA)
- Folic Acid Professional Patient Advice (Wolters Kluwer)
- Folic Acid Monograph (AHFS DI)
- FA-8 MedFacts Consumer Leaflet (Wolters Kluwer)
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