Cyanocobalamin is a synthetic, water-soluble form of Vitamin B12, essential for DNA synthesis, red blood cell formation, and neurological function. The 500mcg strength is a common therapeutic and maintenance dose used to treat and prevent deficiency states, particularly in the Indian population where dietary insufficiency and pernicious anemia are prevalent.
Adult: Deficiency: 500-1000 mcg IM/SC daily for 5-10 days, then 500-1000 mcg weekly for 4 weeks, then 500-1000 mcg monthly for life (in pernicious anemia). Maintenance/Nutritional: 500 mcg IM/SC monthly or 1000-2000 mcg orally daily.
Note: IM/SC route is standard for deficiency treatment. For IM, inject deep into gluteal or deltoid muscle. Oral route is for maintenance/nutritional supplementation, taken with or without food. Intranasal spray is an alternative for maintenance.
Cyanocobalamin acts as a cofactor for two crucial enzymes: 1) Methionine Synthase: Catalyzes the conversion of homocysteine to methionine, which is essential for DNA synthesis and methylation reactions. 2) L-Methylmalonyl-CoA Mutase: Converts methylmalonyl-CoA to succinyl-CoA, a key step in propionate metabolism and myelin synthesis.
Pregnancy: Category A (US FDA). Considered safe. Requirements increase slightly. Deficiency is associated with neural tube defects. Supplementation is recommended in deficient mothers.
Driving: No known effects. However, untreated B12 deficiency can cause neurological symptoms impairing driving ability.
| Chloramphenicol | May decrease hematological response to cyanocobalamin. | Moderate |
| Proton Pump Inhibitors (Omeprazole, Pantoprazole) | Long-term use reduces gastric acid, impairing B12 release from food; may increase requirement. | Moderate |
| Metformin | Chronic use can reduce B12 absorption by interfering with calcium-dependent IF-B12 complex binding. | Moderate |
| Aminoglycosides, Colchicine, Slow-K | May reduce intestinal absorption of B12. | Moderate |
| Folic Acid (high dose) | May mask hematological signs of B12 deficiency, allowing neurological damage to progress. | High |
Same composition (Cyanocobalamin (500mcg)), different brands: