1. Clinical Overview
A fixed-dose combination of two essential B vitamins used primarily for the prevention and treatment of nutritional deficiencies. Folic Acid (Vitamin B9) is crucial for DNA synthesis, red blood cell formation, and neural tube development. Cyanocobalamin (Vitamin B12) is vital for neurological function, red blood cell production, and DNA synthesis. This specific low-dose combination is often used as a maintenance or prophylactic supplement, particularly in the Indian context where dietary deficiencies are common, especially among vegetarians and pregnant women.
| Onset | Duration | Bioavailability |
|---|---|---|
| Hematological response: 24-48 hours. Neurological response (B12): Weeks to months. | Variable; dependent on body stores. Folic Acid: Several weeks. Cyanocobalamin: Hepatic stores can last 3-5 years. | Folic Acid: ~100% from supplements on an empty stomach, reduced to ~85% with food. Cyanocobalamin (Oral): ~1.2% via intrinsic factor-mediated absorption; passive diffusion increases bioavailability at high doses. |
2. Mechanism of Action
Folic Acid acts as a precursor to tetrahydrofolate (THF), a coenzyme involved in one-carbon transfer reactions essential for the synthesis of purines, thymidylate, and amino acids (serine, methionine). This is critical for DNA/RNA synthesis and cell division. Cyanocobalamin is a cofactor for two enzymes: 1) Methionine synthase, which converts homocysteine to methionine using 5-MTHF, linking B12 and folate metabolism. 2) L-methylmalonyl-CoA mutase, which converts methylmalonyl-CoA to succinyl-CoA, crucial for fatty acid and amino acid metabolism.
3. Indications & Uses
- Prophylaxis and treatment of nutritional folate deficiency
- Prophylaxis and treatment of nutritional Vitamin B12 deficiency
- Megaloblastic anemia due to dual deficiency
4. Dosage & Administration
Adult Dosage: One tablet daily, or as directed by the physician. Typically taken after a meal.
Administration: Administer orally with water, preferably after a meal to reduce potential gastric irritation and enhance absorption of fat-soluble vitamins if taken in a multivitamin context. Do not crush or chew unless specified.
5. Side Effects
Common side effects may include:
- Nausea
- Mild diarrhea
- Flushing (feeling of warmth)
- Skin rash/itching
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Phenytoin | Folic acid may decrease phenytoin serum levels, potentially reducing seizure control. Phenytoin may reduce folate levels. | Major |
| Methotrexate | Folic acid can reduce the anti-folate (antineoplastic) efficacy of methotrexate. However, it is used to reduce methotrexate toxicity in rheumatoid arthritis/psoriasis treatment. | Major |
| Pyrimethamine | Folic acid antagonizes the antiprotozoal effect against malaria/toxoplasmosis. | Major |
| Chloramphenicol | May antagonize the hematinic response to Cyanocobalamin in treating anemia. | Moderate |
| Proton Pump Inhibitors (Omeprazole, etc.) | Long-term use reduces gastric acid, impairing protein-bound B12 release from food, potentially worsening deficiency. Does not significantly affect supplemental cyanocobalamin absorption. | Moderate |
| Metformin | Long-term use can reduce Vitamin B12 absorption via calcium-dependent mechanisms, potentially increasing requirement. | Moderate |
| Antiepileptics (Phenobarbital, Primidone) | May reduce serum folate levels. | Moderate |
7. Patient Counselling
- DO take the tablet as prescribed, usually once daily.
- DO take it after a meal to improve tolerance.
- DO inform your doctor if you are pregnant, planning pregnancy, or breastfeeding.
- DO inform your doctor about all other medicines you take, including OTC supplements.
- DONT take this as a substitute for a balanced diet.
- DONT stop medication without consulting your doctor, even if you feel better.
- DONT take double dose to make up for a missed dose.
8. Toxicology & Storage
Overdose: Acute overdose is extremely unlikely due to water solubility and renal excretion. No specific syndrome. Chronic very high doses: Folic Acid (>5 mg/day): May mask B12 deficiency, cause insomnia, malaise, irritability, GI disturbance. Cyanocobalamin: No known toxicity from high doses.
Storage: Store below 30°C, in a cool, dry place. Protect from light and moisture. Keep the container tightly closed. Keep out of reach of children.