This monograph refers to a high-dose oral supplement of Vitamin B, specifically Vitamin B12 (Cyanocobalamin or Methylcobalamin) at 1000 mcg (micrograms, often mislabeled as mg in common parlance). It is a water-soluble vitamin essential for DNA synthesis, red blood cell formation, and neurological function. In the Indian context, it is widely used for managing nutritional deficiencies, peripheral neuropathies (especially diabetic), and as a general tonic.
Adult: Deficiency Treatment: Oral: 1000-2000 mcg once daily for 1-2 months, then maintenance. IM/Deep SC: 1000 mcg daily for 1 week, then weekly for 1 month, then monthly lifelong for pernicious anemia. Maintenance (Oral): 1000-2000 mcg daily or 5000 mcg weekly.
Note: Oral: Take on an empty stomach for best absorption, with water. Sublingual: Place tablet under tongue and allow to dissolve completely. Avoid eating/drinking for 5 minutes. Injectable: For intramuscular or deep subcutaneous administration by healthcare professional.
Vitamin B12 acts as a cofactor for two crucial enzymes: 1) Methionine Synthase: Catalyzes the conversion of homocysteine to methionine, which is essential for DNA/RNA synthesis and myelin sheath maintenance. 2) L-Methylmalonyl-CoA Mutase: Converts methylmalonyl-CoA to succinyl-CoA, a key step in fatty acid and amino acid metabolism.
Pregnancy: Category A (US FDA). Considered safe. Requirements increase slightly. Recommended for deficient mothers to prevent neural tube defects. Oral 1000 mcg/day is safe.
Driving: No known effects. However, dizziness from underlying anemia may impair ability.
| Chloramphenicol | May decrease hematologic response to Vitamin B12 | Moderate |
| Proton Pump Inhibitors (Omeprazole) | Long-term use reduces gastric acid, impairing B12 release from food but not from supplements. | Low |
| Metformin | Chronic use can reduce B12 absorption by interfering with calcium-dependent IF-B12 complex binding. | Moderate |
| Colchicine | May impair B12 absorption via intestinal mucosa damage. | Moderate |
| Aminosalicylic acid | Reduces oral B12 absorption. | Moderate |
| Antiepileptics (Phenytoin, Phenobarbital) | May reduce serum B12 levels; mechanism unclear. | Low |
Same composition (Vitamin B (1000mg)), different brands: