Treatment and prophylaxis of vitamin B12 deficiency in case of:
Terminal ileon resection;
It is given as intramuscular injection as a maintenance treatment: 100 μg cyanocobalamin (2 vials ZIMAVA 50 mg / ml) once a month.
Known hypersensitivity to cyanocobalamin, to related substances or to any of the excipients of the product.
Treatment with vitamin B12 will be established once the type of anemia is established, otherwise treatment with vitamin B12 will mask the type of pre-existing anemia.
No cases of overdose have been reported.
Mechanism of action
Cyanocobalamin is a hematopoietic factor and has antianemic action.
Administration of vitamin B12 to patients with pernicious anemia or other forms of B12 avitaminosis rapidly results in a clinically and biologically spectacular improvement. From the first days, patients experience improvement in clinical condition, mental condition improves, appetite increases, dry mouth. Normoblastic transformation of the marrow begins at 8 hours after the first injection and is complete after two days. Sideremia decreases due to the production of hemoglobin (which makes it necessary to supplement the iron). After 2-3 days the number of reticulocytes increases, reticulocytosis being maximum at 5-10 days. Concomitant increases hematocrit and plasma volume. The number of red blood cells starts to rise after reticulocytosis, reaching normal within 4-8 weeks. Thrombocytopenia (if present) is corrected in about 10 days and leucopenia in 2 weeks.
Hematologic response can be diminished and delayed in the presence of active infections, renal disease, hypothyroidism, cancer as well as alcohol abuse.
Cyanocobalamin binds to specific plasma proteins called transcobalamines. Transcobalamin appears to be involved in the rapid transport of cobalamin to the tissues. Cyanocobalamin is stored in the liver, excreted in the bile, and enters the enterohepatic circulation. Some of the administered dose is excreted in the urine, mostly in the first 8 hours. Vitamin B12 crosses the placenta and passes into breast milk.
The maximum plasma concentration is reached one hour after the intramuscular injection of a dose.