Vitamin B12 (Methylcobalamin)
Generic Name: Methylcobalamin / Cyanocobalamin
Seek Urgent Medical Attention If:
Severe ataxia, progressive limb paralysis (subacute combined spinal degeneration).
Uses & Medical Indications
Treatment and prevention of Vitamin B12 deficiency, megaloblastic/macrocytic anemia, peripheral neuropathy, diabetic neuropathy, and post-gastrectomy or strict vegetarian/vegan nutritional replenishment.
Vitamin B12 Deficiency, Megaloblastic Anemia, Peripheral Neuropathy, Diabetic Neuropathy
Dosage & Administration Guidelines
Dietary deficiency / Maintenance: 1000 mcg to 1500 mcg orally once daily. Severe neurological symptoms / Malabsorption: 1000 mcg IM alternate days for 1-2 weeks, then weekly, then monthly maintenance.
Adjust based on age and severity (typically 5 to 50 mcg daily).
1000 mcg daily orally or sublingually due to high prevalence of atrophic gastritis and hypochlorhydria.
Water-soluble; excess is excreted harmlessly in urine.
No adjustment required.
No adjustment required.
Side Effects & Safety Warnings
Generally none; rare mild transient diarrhea or skin rash.
Extremely rare; hypokalemia during initial rapid reticulocyte proliferation in severe pernicious anemia.
Hypersensitivity to cobalt or methylcobalamin.
Folic acid alone must not be used to treat B12 deficiency; folate corrects the anemia but allows irreversible neurological spinal cord degeneration (subacute combined degeneration) to progress.
Interactions (Drugs, Food & Alcohol)
Metformin, Proton Pump Inhibitors (Omeprazole, Pantoprazole), H2 Blockers, Colchicine (all reduce intestinal B12 absorption with chronic use).
Can be taken with or without food.
Heavy alcohol consumption impairs intestinal B12 absorption and hepatic storage.
Pregnancy & Breastfeeding Safety
Safe and vital during pregnancy for fetal neural tube and brain development.
Essential for nursing infants; strict vegetarian mothers must supplement to prevent infantile B12 deficiency.
Patient Counseling & Practical Advice
If using sublingual tablets, place under the tongue and allow to dissolve completely. Patients on long-term Metformin or Omeprazole should have B12 checked every 1-2 years.
Take when remembered.
Complete blood count (MCV, hemoglobin), serum Vitamin B12, serum methylmalonic acid (MMA) or homocysteine.
Frequently Asked Questions
Related Medicines in Vitamin
Content for Vitamin B12 (Methylcobalamin) was synthesized and fact-checked against standardized regulatory monographs, official pharmacopoeias, and national health authorities:
- NIH Office of Dietary Supplements — Vitamin B12 Fact Sheet for Health Professionals
The information provided on this website is for educational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a qualified healthcare provider with any questions you may have regarding a medical condition.