Skip to Content


Generic Name: riboflavin (vitamin B2) (RYE bow flay vin)
Brand Name: B2-400, Vitamin B2

Medically reviewed by on Jul 31, 2020 – Written by Cerner Multum

What is B2-400?

B2-400 is vitamin B2. Vitamins are naturally occurring substances necessary for many processes in the body. This medicine is important in the maintenance of many tissues of the body.

B2-400 is used to treat or prevent deficiencies of riboflavin.

B2-400 may also be used for purposes not listed in this medication guide.

Important Information

Follow all directions on your medicine label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.

Before taking this medicine

Ask a doctor or pharmacist if it is safe for you to use B2-400 if you have other medical conditions, especially:

B2-400 is considered likely safe to use during pregnancy, but your dose needs may be different during this time. You should not use this medicine without a doctor's advice if you are pregnant.

B2-400 is considered possibly safe to use while nursing, and your dose needs may be different during this time. Do not use this medicine without a doctor's advice if you are breast-feeding.

Do not give B2-400 to a child without medical advice.

How should I take B2-400?

Use exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended.

The recommended dietary allowance of riboflavin increases with age. Follow your healthcare provider's instructions. You may also consult the Office of Dietary Supplements of the National Institutes of Health, or the U.S. Department of Agriculture (USDA) Nutrient Database (formerly "Recommended Daily Allowances") listings for more information.

Store at room temperature away from moisture and heat.

What happens if I miss a dose?

Skip the missed dose if it is almost time for your next scheduled dose. Do not use extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while taking B2-400?

Follow your healthcare provider's instructions about any restrictions on food, beverages, or activity.

B2-400 side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor if you have diarrhea or increased urination. These could be signs that you are using too much B2-400.

B2-400 may cause your urine to turn a yellow-orange color, but this is usually not a harmful side effect.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect B2-400?

Other drugs may interact with riboflavin, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

More about B2-400 (riboflavin)

Consumer resources

Other brands: Vitamin B2

Professional resources

Related treatment guides