Common use

Folic acid (vitamin B9) is a B vitamin supplement that may be used to prevent and treat folate deficiency (low blood levels of folate) that can cause megaloblastic anemia. Folic acid may also be used to control high levels of homocysteine, prevent serious birth defects in pregnant women or women who think they may be pregnant, and prevent methotrexate-induced folate deficiency in people prescribed methotrexate.

Dosage and direction

Take folic acid exactly as prescribed by your doctor. Do not take it in larger amounts or for longer than recommended. Folic acid tablets are usually taken by mouth with a full glass of water. Folic acid is an important nutrient and folate or folic acid should be consumed daily. The recommended dietary allowance (RDA) of folic acid for adults is 400 mcg DFE (dietary folate equivalents) daily.

Precautions

Ask a doctor or pharmacist if this medicine is safe to use if you have ever had: epilepsy or other seizure disorder; cirrhosis or other liver disease; kidney disease (or if you are on dialysis); hemolytic anemia; pernicious anemia; anemia that has not been diagnosed by a doctor and confirmed with laboratory testing; a condition that affects how well you absorb nutrients, such as celiac disease or inflammatory bowel disease; an infection or alcoholism.
Tell your doctor if you are pregnant or breastfeeding.

Contraindications

You should not use this medicine if you have ever had an allergic reaction to folic acid.

Possible side effect

Folic acid side effects are more likely to occur with higher dosages of folic acid (up to 15 mg/day) and include: nausea; loss of appetite; bloating or gas; stomach pain; bitter or unpleasant taste in your mouth; confusion or trouble concentrating; sleep problems; mood changes, such as depression or excitement impaired judgment.

Drug interaction

Ask a doctor or pharmacist before using folic acid with any other medications, especially: methotrexate; nitrofurantoin; pyrimethamine; tetracycline (false low serum and red cell folate levels may occur with some antibiotics that suppress the growth of Lactobacillus casei); a barbiturate such as phenobarbital or secobarbital; seizure medicine such as phenytoin or primidone (the anticonvulsant action of some seizure medications can be antagonized by folic acid and increased dosages of the anticonvulsant may be needed); sulfasalazine (may reduce the body's ability to absorb folate).

Missed dose

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

Overdose

Call your healthcare provider or seek emergency medical attention.

Storage

Store folic acid at room temperature, away from moisture and heat. Keep away from children and pets.