Folic Acid

Reviewed on 12/15/2021

What Is Folic Acid and How Does It Work?

Folic Acid is a prescription medication used as nutritional supplementation, as prophylaxis for Neural Tube Defects, and treatment of Folic Acid Deficiency and Methanol Toxicity.

  • Folic Acid is available under the following different brand names: Folvite 

What Are Dosages of Folic Acid?

Adult and Pediatric dosage


  • 400mcg
  • 800mcg
  • 1mg

Injectable solution

  • 5mg/mL

Nutritional Supplementation

Adult dosage

  • Males: 400 mcg/day orally
  • Females: 400-800 mcg/day orally
  • Pregnant women: 600 mcg/day orally
  • Nursing women: 500 mcg/day orally
  • Upper limit: 1 mg/day orally  

Pediatric dosage 

  • Children 0-6 months: 65 mcg/day orally
  • Children 7-12 months: 80 mcg/day orally
  • Children 1-4 years: 150 mcg/day orally
  • Children 4-9 years: 200 mcg/day orally
  • Children 9-14 years: 300 mcg/day orally 
  • Children 14-18 years: 400 mcg/day orally
  • Upper limit: children 1-4 years, 300 mcg/day orally; children 4-8 hours, 400 mcg/day orally

Neural Tube Defects Prophylaxis

  • Females of childbearing potential: 400 mcg/day orally
  • Pregnancy women: 600 mcg/day orally
  • Females with high risk or family history of neural tube defects: 4 mg/day orally

Folic Acid Deficiency

  • Adult dosage
  • 0.4-1 mg orally/IV/IM/SC once daily

Pediatric dosage

  • Infants: 15 mcg/kg/day or 50 mcg/day IV/Orally/IM/SC
  • Children 1-10 years of age: 1 mg/day IV/Orally/IM/SC initially, then 0.1-0.4 mg/day

Methanol Toxicity

Adult dosage

  • 50-75 mg IV every 4 hours for 24 hours

Pediatric dosage

  • 1 mg/kg IV every 4 hours for 24 hours

Dosage Considerations – Should be Given as Follows: 

  • See "Dosages."

What Are Side Effects Associated with Using Folic Acid?

Common side effects of Folic Acid include:

  • nausea, 
  • loss of appetite, 
  • bloating, 
  • gas, 
  • stomach pain, 
  • bitter or unpleasant taste in the mouth, 
  • confusion, 
  • trouble concentrating, 
  • sleep problems, 
  • depression, 
  • irritableness, and
  • excitement 

Serious side effects of Folic Acid include:

  • hives, 
  • difficulty breathing, 
  • swelling of the face, lips, tongue, or throat, 
  • rash, 
  • itching, 
  • skin redness, and
  • wheezing

Rare side effects of Folic Acid include:

  • none 
This is not a complete list of side effects and other serious side effects or health problems may occur as a result of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

What Other Drugs Interact with Folic Acid?

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them.  Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider or pharmacist first

  • Folic Acid has severe interactions with no other drugs.
  • Folic Acid has serious interactions with no other drugs.
  • Folic Acid has moderate interactions with the following drugs:
  • Folic Acid has minor interactions with at least 44 other drugs. 

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drugs interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use.  Keep a list of all your medications with you, and share this information with your doctor and pharmacist.  Check with your health care professional or doctor for additional medical advice, or if you have health questions, concerns.

What Are Warnings and Precautions for Folic Acid?


  • Hypersensitivity

Effects of drug abuse

  • None

Short-Term Effects

  • See “What are Side Effects Associated with Using Folic Acid?”

Long-Term Effects

  • See “What Are Side Effects Associated with Using Folic Acid?”


  • Undiagnosed anemias
  • May mask anemia at dosages over 0.1 mg/day
  • In presence of vitamin B12 deficiency, not appropriate for monotherapy in pernicious, normocytic, or aplastic anemia
  • Vials must be protected from heat and light
  • Injection contains benzyl alcohol as preservative (benzyl alcohol is associated with gasping syndrome in neonates)

Pregnancy and Lactation

  • Use in pregnancy is generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk. 
  • Drug enters breast milk; safe for nursing.

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