Folate (Folic Acid) : Safety and Interactions

by MedlinePlus

(Page 3 of 4)

Safety

Allergies

Avoid folic acid supplements if you are hypersensitive or allergic to any of the product ingredients.

Side Effects and Warnings

General: Folate appears to be well tolerated in recommended doses. Stomatitis, alopecia, myelosupression, and zinc depletion have been reported.

Cardiovascular: An intravenous loading dose of folic acid, vitamin B6 and vitamin B12 followed by oral administration of folic acid 1.2mg plus vitamin B6 48mg and vitamin B12 60mcg, taken daily after coronary stenting, might actually increase restenosis rates. Due to the potential for harm, this combination of vitamins should not be recommended for patients receiving coronary stents.

Dermatologic: Erythema, pruritus, urticaria, skin flushing, rash, and itching have been reported.

Gastrointestinal: Nausea, bloating, flatulence, cramps, bitter taste and diarrhea have been reported. Very high doses of 15mg per day can cause significant gastrointestinal side effects.

Neurologic/psychiatric: Irritability, excitability, general malaise, altered sleep patterns, vivid dreaming, overactivity, confusion, impaired judgment, increased seizure frequency and psychotic behavior have been reported. Doses above 1000mcg per day should be avoided if possible to prevent neuropathy related to vitamin B12 deficiency. However, there is some evidence that doses of 5mg per day orally for up to 4 months can be used safely if vitamin B12 levels are routinely measured. Very high doses of 15mg per day can cause significant central nervous system (CNS) side effects. Supplemental folic acid might increase seizures in people with seizure disorders, particularly in very high doses. Doses less than 1000mcg have rarely been associated with increased seizure activity.

Respiratory: Anaphylaxis and bronchospasm have been reported.

Genitourinary: Color of urine may become more intense.

Hematologic:Folic acid may mask the symptoms of pernicious, aplastic, or normocytic anemias caused by vitamin B12 deficiency and may lead to neurological damage. Doses greater than 100mcg per day have been reported to obscure pernicious anemia with continuing irreversible nerve damage progression. Folate deficiency is a cause megaloblastic anemia.

Pregnancy and Breastfeeding

Pregnancy: It is recommended that all women capable of becoming pregnant consume 400 micrograms daily from supplements or fortified foods in addition to intake of food folate from a varied diet, in order to reduce the risk of the fetus developing a neural tube defect. Women should continue consuming 400 micrograms daily from supplements or fortified food until their pregnancy is confirmed and they enter prenatal care. Folic acid supplementation is recommended to be used by pregnant women in doses below 0.8mg (800mcg) daily (FDA Pregnancy Category A). Folic acid supplementation in doses higher than 0.8mg (800mcg) daily is categorized as FDA Pregnancy Category C.

Breastfeeding: Folic acid is present in the breast milk and is likely safe to use during breastfeeding under the supervision of a qualified healthcare provider.

Interactions

Most herbs and supplements have not been thoroughly tested for interactions with other herbs, supplements, drugs, or foods. The interactions listed below are based on reports in scientific publications, laboratory experiments, or traditional use. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy.

Interactions with Drugs

Alcohol: Excessive use of alcohol increases the requirement for folic acid.

Aminosalicylic Acid (para-aminosalicylic acid, PAS, Paser): Aminosalicylic acid can reduce dietary folate absorption, worsening the folate deficiency often seen with active tuberculosis, or preventing its reversal during treatment. Megaloblastic anemia occurs rarely and usually when there are other contributing factors, such as concurrent vitamin B12 malabsorption. Patients being treated for tuberculosis may be advised to take folic acid supplements if their dietary folate intake is low.

Antacids: Chronic use of large doses of antacids can reduce folic acid absorption, but this is likely only significant if dietary folate intake is very low. Maintenance of the recommended daily intake of folic acid in the diet is recommended.

Antibiotics:Antibiotic therapy can disrupt the normal gastrointestinal (GI) flora, interfering with absorption of folic acid. Folate supplements are not considered necessary.

Aspirin: Aspirin may decrease serum folate levels, especially with chronic large doses. It is suggested that folate is just being redistributed in the body rather than an actual folate deficiency; therefore folate supplementation is not considered necessary.

Birth control pills: Oral contraceptives may impair folate metabolism producing depletion, but the effect is unlikely to cause anemia or megaloblastic changes.

Carbamazepine (Tegretol®): Carbamazepine can reduce serum folate levels, but megaloblastic anemia has not been reported. Pregnant women taking carbamazepine may be especially at risk from reduced folate levels. However, folic acid supplements have worsened seizure control in some people with epilepsy.

Chloramphenicol: Chloramphenicol may antagonize some effects of folic acid on the blood (hematopoietic system).

Cholestyramine (Questran®): Cholestyramine reduces folic acid absorption. It can lower serum and red blood cell folate levels in children taking large doses (0.2 to 1.1 grams/kg per day) for several months. Maintenance of dietary folate intake is recommended.

Colestipol (Colestid®): Colestipol can interfere with absorption of folic acid, and reduced serum folate levels may occur. Maintenance of dietary folate intake is recommended.

Cycloserine (Seromycin Pulvules®): Cycloserine can reduce serum folate levels, and rare cases of megaloblastic anemia have occurred. Maintenance of dietary folate intake is recommended.

Diuretics: Limited data suggests that diuretics ("water pills") may increase excretion of folic acid. Reduced red blood cell folate levels, possibly contributing to increased homocysteine levels, a risk factor for cardiovascular disease, were found in one group of people taking diuretics for six months or longer. The need for folic acid supplementation during diuretic therapy requires further study before a firm recommendation can be made. Currently, maintenance of dietary folate intake is recommended.

Estrogens: Reduced serum and red blood cell folate levels can occur in some women taking conjugated estrogens (Premarin®) or oral contraceptives, but this is unlikely in women with adequate dietary folate intake. There are rare reports of megaloblastic anemia associated with oral contraceptive use, usually in women with other conditions contributing to folate deficiency. There is some evidence that oral contraceptives can increase the rate of progression of cervical dysplasia to cervical cancer, and that folic acid can slow or reverse this dysplasia. Supplements are recommended only for those women with inadequate dietary intake or other conditions that contribute to folate deficiency, and for those diagnosed with, or at increased risk for, cervical dysplasia (due to family history for example).

H2 blockers: Folic acid absorption from the small intestine is optimal at pH 5.5 to 6. The increased pH associated with use of H2 blockers (such as cimetidine (Tagamet®), famotidine (Pepcid®), nizatidine (Axid®), and ranitidine (Zantac®)), may therefore reduce folic acid absorption, but this is probably only significant if dietary folate intake is very low. Maintenance of dietary folate intake is recommended.

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