G-Vitamin B2

Approved Indications:

• Riboflavin deficiency (ariboflavinosis): Treatment and prevention of clinical and subclinical vitamin B2 deficiency.
• Nutritional supplementation: Used in multivitamin preparations for individuals with increased requirements (e.g., during pregnancy, lactation, infection, or chronic illness).
• Migraine prophylaxis: High-dose riboflavin (typically 400 mg daily) is used for the prevention of migraine headaches in adults and adolescents.
• Metabolic disorders: Adjunct treatment in conditions such as:
• Riboflavin transporter deficiency (Brown-Vialetto-Van Laere syndrome)
• Multiple acyl-CoA dehydrogenase deficiency (MADD)
• Glutaric aciduria type II
• Ophthalmic use: As a photosensitizer in corneal collagen cross-linking therapy for keratoconus and ectatic corneal disorders (used topically).

Adults:

• Riboflavin deficiency: 5–30 mg orally once daily until deficiency is corrected.
• Migraine prophylaxis: 400 mg orally once daily.
• General supplementation: 1.1 mg/day (females), 1.3 mg/day (males), or as part of multivitamin.

Pediatric Dosage:

• Deficiency treatment:
• Infants: 1–5 mg/day orally.
• Children: 3–10 mg/day orally.
• Migraine prophylaxis (≥12 years): 200–400 mg/day orally.

Metabolic disorders (all ages):

• 100–400 mg/day in divided doses depending on severity and condition.

Elderly:

• Same as adult dose; no specific adjustment unless renal/hepatic impairment is present.

Special Populations:

• Renal or hepatic impairment: No routine dose adjustment; monitor if severe dysfunction.

Route of Administration:

• Oral (tablets/capsules)
• Parenteral (IV or IM for severe deficiency)
• Ophthalmic (topical drops for corneal cross-linking procedures)

Riboflavin (Vitamin B2) functions as a precursor to the coenzymes flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD). These cofactors are essential for numerous oxidation-reduction (redox) reactions involved in energy metabolism, including the mitochondrial electron transport chain, fatty acid oxidation, and amino acid catabolism. Riboflavin also supports antioxidant defense through glutathione metabolism and promotes cellular repair and growth.

• Absorption: Absorbed primarily in the proximal small intestine via active transport; passive diffusion at higher doses.
• Bioavailability: ~60%; saturable above 30–50 mg single dose.
• Distribution: Widely distributed; highest in liver, heart, and kidneys. Moderate plasma protein binding.
• Metabolism: Converted to FMN and FAD in tissues, primarily the liver.
• Excretion: Excreted in urine mainly as unchanged riboflavin and metabolites; imparts a bright yellow color to urine.
• Half-life: Approximately 1–2 hours after oral administration.

• Pregnancy: Category A (considered safe). Riboflavin is essential for fetal development and is routinely included in prenatal vitamins.
• Lactation: Safe during breastfeeding; secreted in small amounts in breast milk to support neonatal growth.
• High-dose use in pregnancy or lactation should be under medical supervision.

• Primary Class: Water-soluble vitamin
• Pharmacological Group: Vitamin B complex (B2)

• Hypersensitivity to riboflavin or any ingredient in the formulation
• Rare hereditary disorders (e.g., riboflavin transporter mutations) may require specialized dosing

• Riboflavin may cause benign yellow-orange discoloration of urine.
• High doses may cause gastrointestinal discomfort.
• Riboflavin is photosensitive: exposure to light can degrade the vitamin in solutions.
• Use with caution in patients with severe renal or hepatic impairment if high doses are administered.

Common (usually benign):

• Yellow-orange urine (non-harmful)
• Diarrhea
• Gastrointestinal upset (with high doses)

Uncommon/Rare:

• Allergic reaction (rash, itching, swelling)
• Photosensitivity reactions (especially with topical or parenteral use)
• Nausea or abdominal pain (with very high doses >400 mg/day)

• Chronic alcohol use: May impair riboflavin absorption.
• Anticholinergic drugs: May decrease gastrointestinal absorption.
• Probenecid: May reduce renal excretion of riboflavin.
• Tricyclic antidepressants & phenothiazines: May reduce riboflavin absorption.
• Tetracycline antibiotics: High doses of riboflavin may reduce antibiotic absorption if taken concurrently.

• Migraine Prophylaxis: Riboflavin 400 mg/day is supported by recent guidelines (neurology societies) as a safe and effective preventive option.
• Genetic Metabolic Disorders: Riboflavin continues to be explored for its benefits in mitochondrial disorders and transporter deficiencies, with genetic screening recommended before initiation.
• Parenteral Nutrition: WHO and ESPEN recommend riboflavin inclusion in pediatric and adult total parenteral nutrition (TPN) regimens.

• Temperature: Store below 25°C.
• Light protection: Riboflavin is light-sensitive; protect from sunlight and UV radiation.
• Form-specific guidance:
• Tablets/Capsules: Store in a dry place, tightly closed container.
• Injectable solution: Protect from light; do not freeze.
• Ophthalmic solution: Use immediately after opening; store in original light-protective packaging.