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(RYE boe flay vin)

Index Terms

  • Lactoflavin
  • Vitamin B2
  • Vitamin G

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Capsule, Oral:

B-2-400: 400 mg

Generic: 50 mg

Tablet, Oral:

Generic: 25 mg, 50 mg, 100 mg

Brand Names: U.S.

  • B-2-400 [OTC]

Pharmacologic Category

  • Vitamin, Water Soluble


Component of flavoprotein enzymes that work together, which are necessary for normal tissue respiration; also needed for activation of pyridoxine and conversion of tryptophan to niacin


Readily via GI tract; increased with food




9% eliminated unchanged in urine

Half-Life Elimination

Biologic: 66 to 84 minutes

Use: Labeled Indications

Dietary supplement

Dosing: Adult

Dietary supplement: Oral: 100 mg once or twice daily

Recommended daily intake:

≥19 years: Females: 1.1 mg; Males: 1.3 mg

Pregnancy: 1.4 mg

Lactation 1.6 mg

Dosing: Geriatric

Refer to adult dosing.

Dosing: Pediatric


Adequate intake:

1-6 months: 0.3 mg/day

7-12 months: 0.4 mg/day

Recommended daily intake:

1-3 years: 0.5 mg

4-8 years: 0.6 mg

9-13 years: 0.9 mg

14-18 years: Females: 1 mg; Males: 1.3 mg

Dietary Considerations

Dietary sources of riboflavin include liver, kidney, dairy products, green vegetables, eggs, whole grain cereals, yeast, and mushroom.


Protect from light.

Drug Interactions

There are no known significant interactions.

Test Interactions

Large doses may interfere with urinalysis based on spectrometry; may cause false elevations in fluorometric determinations of catecholamines and urobilinogen

Adverse Reactions

Frequency not defined: Genitourinary: Urine discoloration (yellow-orange)


Other warnings/precautions:

• Vitamin deficiency: Single vitamin deficiency is rare; evaluate for other deficiencies.

Pregnancy Considerations

Water-soluble vitamins cross the placenta. Riboflavin requirements may be increased in pregnant women compared to nonpregnant women (IOM, 1998).

Patient Education

• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)

• Patient may experience urine discoloration (HCAHPS).

• Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for health care professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience, and judgment in diagnosing, treating, and advising patients.