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2. Summary
BETOLVEX® is a long-acting (depot) vitamin B12 medicinal product containing cyanocobalamin, primarily formulated for intramuscular administration. Its distinctive feature is an oil-based cyanocobalamin–tannin complex, which produces a sustained release from the injection site, enabling prolonged maintenance of serum and hepatic vitamin B12 levels.
BETOLVEX® is indicated for the treatment and prevention of vitamin B12 deficiency, particularly in conditions associated with malabsorption or depleted body stores, such as pernicious anemia and post-gastrectomy states.
3. Brand Name
BETOLVEX®
4. Category
- Vitamin and mineral preparation
- Hematinic / Antianemic agent
- Vitamin B12 (cobalamin) supplement
- Depot (prolonged-release) formulation
5. Active Ingredient
Cyanocobalamin (Vitamin B12)
Synthetic cobalt-containing corrinoid compound.
6. Pharmaceutical Form & Strength
Injectable (primary formulation):
- Intramuscular prolonged-release suspension
- Strength: 1 mg/mL cyanocobalamin
- Presentation: 1 mL ampoules or 1 mL pre-filled syringes
- Excipients: sesame oil, aluminium monostearate, tannin complex
Oral tablets (legacy/market-dependent):
- 1 mg cyanocobalamin per tablet
Availability varies by country and current authorization status
7. Manufacturer & Marketing Authorization Holder
MINAPHARM Pharmaceuticals – Egypt
Note: Older documentation may reference alternative spellings or legacy entities; MINAPHARM is the verified current manufacturer/MAH.
8. Mechanism of Action
Cyanocobalamin is converted intracellularly into the active coenzyme forms:
- Methylcobalamin
- Adenosylcobalamin
Vitamin B12 is essential for:
- DNA synthesis and normal erythropoiesis
- Methionine synthesis and homocysteine metabolism
- Myelin formation and neurological function
- Fatty acid and amino acid metabolism
Formulation-specific mechanism:
The cyanocobalamin–tannin complex suspended in an oil-based aluminium monostearate gel creates an intramuscular depot, allowing gradual release over weeks to months, resulting in sustained systemic exposure and effective hepatic store replenishment.
9. Spectrum of Activity
Not applicable.
BETOLVEX® is a nutritional/vitamin preparation and has no antimicrobial or antiviral activity.
10. Pharmacokinetics
- Absorption: Slow, prolonged absorption following deep intramuscular injection
- Distribution: Binds to transcobalamins; widely distributed, with major storage in the liver
- Metabolism: Converted in tissues to active coenzyme forms
- Elimination: Excess excreted mainly via urine; significant enterohepatic circulation
- Duration of action: Extended due to depot formulation, permitting quarterly maintenance dosing
11. Indications
- Pernicious anemia (treatment and prophylaxis)
- Vitamin B12 deficiency following:
- Total or partial gastrectomy
- Ileocecal resection or proctocolectomy
- Bariatric or intestinal bypass surgery
- Malabsorption syndromes (e.g., sprue, steatorrhea, celiac disease)
- Megaloblastic (macrocytic) anemia due to B12 deficiency
- Neurological manifestations of B12 deficiency
- Nutritional deficiency (elderly, atrophic gastritis, strict vegetarians/vegans)
- Drug-associated deficiency (e.g., metformin, long-term acid-suppressive therapy)
12. Administration
- Route: Intramuscular (IM) only
- Site: Deep IM injection (gluteal muscle preferred)
- Important: Must not be administered intravenously or subcutaneously due to oil-based formulation
13. Method of Preparation
BETOLVEX® injection is supplied ready to use.
- No dilution or reconstitution required
- Do not mix with other medications
- Gentle inversion may be used if separation is observed
- Vigorous shaking is not recommended
14. Contraindications
- Hypersensitivity to cyanocobalamin, cobalt, or any excipients (notably sesame oil)
- Leber’s hereditary optic neuropathy
- Tobacco–alcohol amblyopia
- Tropical atoxic neuropathy
15. Warnings & Precautions
- Confirm vitamin B12 deficiency before long-term therapy
- Hypokalemia: May occur during early intensive treatment due to rapid erythropoiesis; monitor potassium
- Rare but serious hypersensitivity reactions, including anaphylaxis
- Use caution in patients with optic nerve disorders
- Not a substitute for full diagnostic evaluation of anemia
16. Drug Interactions
- Chloramphenicol: May antagonize hematologic response
- Metformin: Reduces B12 absorption (monitor levels)
- Proton pump inhibitors / H₂ blockers: Long-term use may contribute to deficiency
- Colchicine, heavy alcohol use: May impair absorption
- Nitrous oxide: Functional B12 inactivation (clinically significant)
17. Side Effects
Generally well tolerated.
Common:
- Injection site pain, redness, induration
Uncommon:
- Pruritus, rash, mild gastrointestinal upset
Rare:
- Hypersensitivity reactions, including anaphylaxis
- Hypokalemia during initial therapy
18. Use in Special Populations
- Pregnancy: Safe when used at recommended doses
- Lactation: Compatible; vitamin B12 is excreted in breast milk
- Elderly: Frequently indicated; no routine dose adjustment
- Renal or hepatic impairment: No standard adjustment required; clinical judgment advised
- Pediatrics: Use under specialist supervision; depot formulation data are limited
19. Storage Conditions
- Store according to manufacturer’s instructions (typically below 25°C)
- Protect from light
- Do not freeze
- Keep out of reach of children
20. Additional Sections
Overdosage:
Vitamin B12 has a wide safety margin. Clinically relevant toxicity is extremely rare.
Duration of Therapy:
Lifelong therapy may be required in irreversible malabsorption (e.g., pernicious anemia)
21. Frequently Asked Questions (FAQ)
Q1: Why is BETOLVEX® given every 3 months?
A: Because its depot formulation releases vitamin B12 slowly, maintaining therapeutic levels longer than aqueous injections.
Q2: Can oral tablets replace injections?
A: In mild deficiency or normal absorption, high-dose oral B12 may be effective. In pernicious anemia or malabsorption, IM injections remain preferred.
Q3: Is long-term use safe?
A: Yes. Long-term vitamin B12 replacement is generally safe and often necessary.
22. References
- MINAPHARM BETOLVEX® Product Information (legacy and current documentation)
- British National Formulary (BNF) – Cyanocobalamin
- Martindale: The Complete Drug Reference
- NICE Clinical Knowledge Summaries: Vitamin B12 deficiency
- NIH Office of Dietary Supplements – Vitamin B12 Fact Sheet
- Langan RC, Goodbred AJ. Am Fam Physician. 2017
