Pharmacological properties
Pharmacodynamics. Vitamin B12 (cyanocobalamin) has a metabolic, hematopoietic effect. In the body (mainly in the liver) it is converted into a coenzyme form - adenosylcobalamin, or cobamamide, which is the active form of vitamin B12. Cobamamide is a part of numerous enzymes, including the reductase that reduces folic acid to tetrahydrofolic acid. It has high biological activity. Cobamamide is involved in the transfer of methyl and other one-carbon fragments, therefore it is necessary for the formation of deoxyribose and DNA, creatine, methionine - a donor of methyl groups, in the synthesis of lipotropic factor - choline, for the conversion of methylmalonic acid into succinic acid, which is part of myelin, for the utilization of propionic acid. Cobamamide is necessary for normal hematopoiesis, as it promotes the maturation of erythrocytes. participates in the synthesis and accumulation in erythrocytes of compounds containing sulfhydryl groups, which increases their tolerance to hemolysis. activates the blood coagulation system, in high doses causes an increase in thromboplastic activity and prothrombin activity. reduces the level of cholesterol in the blood. has a positive effect on the function of the liver and nervous system. increases the ability of tissues to regenerate.
Pharmacokinetics. When administered parenterally, vitamin B 12 quickly enters the systemic bloodstream. In the blood, it binds to transcobalamin I and II, which transports it to the tissues. It is deposited in the liver. The connection with plasma proteins is 90%. The time to reach maximum concentration (T max) after s / c or i / m administration is about 1 hour. It is excreted from the liver with bile into the intestines and is reabsorbed into the blood. T ½ from the liver is 500 days. It is excreted with normal kidney function: 7-10% - by the kidneys, about 50% - with feces; with reduced kidney function: 0-7% - by the kidneys, 70-100% - with feces. Penetrates the placental barrier.
Indication
Treatment of malignant, posthemorrhagic and iron deficiency anemias, aplastic anemia in children, nutritional anemias caused by toxic substances and drugs associated with vitamin B12 deficiency, regardless of the cause of the deficiency (gastric resection, helminthic invasions, impaired absorption in the intestine, pregnancy). polyneuritis, trigeminal neuralgia, radiculitis, causalgia, migraine, diabetic neuritis, amyotrophic lateral sclerosis, cerebral palsy, Down's disease, alcoholic delirium. Use for dystrophy in children, after infectious diseases, for sprue (together with folic acid), liver diseases (hepatitis, cirrhosis, Botkin's disease), radiation sickness, psoriasis, dermatitis herpetiformis, neurodermatitis, photodermatoses.
Application
The drug should be administered subcutaneously, intramuscularly, intravenously, and in the case of lateral funicular myelosis and amyotrophic sclerosis, also intralumbarly.
adults
In case of B12 deficiency anemia, the drug should be used in doses of 100-200 mcg (0.1-0.2 mg) every other day until remission is achieved.
When symptoms of funicular myelosis appear and in macrocytic anemias with damage to the nervous system, cyanocobalamin is used in a single dose of 400-500 mcg (0.4-0.5 mg) and more. During the 1st week, administer daily, and then at intervals of 5-7 days (at the same time prescribe folic acid). In severe cases, inject into the spinal canal, starting with a single dose of 15-30 mcg, with each subsequent injection, increase the dose (50; 100; 150; 200 mcg). Intralumbar injections are given every 3 days, a total of 8-10 injections are required per course. During the period of remission, in the absence of funicular myelosis, for maintenance therapy, 100 mcg is prescribed 2 times a month, in the presence of neurological symptoms - 200-400 mcg 2-4 times a month.
In amyotrophic lateral sclerosis, encephalomyelitis, neurological diseases with pain syndrome, the drug is administered in increasing doses from 200 to 500 mcg per injection (with improvement - 100 mcg/day). The course of treatment is 14 days.
In case of peripheral nerve injury, administer 200-400 mcg once every 2 days for 40-45 days.
For hepatitis and cirrhosis, prescribe 15-30 mcg/day or 100 mcg every other day for 25-40 days.
For diabetic neuropathy, sprue, radiation sickness, administer 60-100 mcg daily for 20-30 days.
In case of vitamin B12 deficiency, treatment is carried out intramuscularly and intravenously at a dose of 1 mg daily for 1-2 weeks, the maintenance dose is 1-2 mg intramuscularly or intravenously from 1 time per week to 1 time per month. The duration of treatment with cyanocobalamin and repeated courses depend on the course of the disease and the effectiveness of treatment.
children
Enter only s / c.
For posthemorrhagic and iron deficiency anemia, prescribe 30-100 mcg 2-3 times a week.
For aplastic anemia in children, administer 100 mcg until clinical and hematological improvement occurs.
For nutritional anemia in children, prescribe 30 mcg for 15 days.
For dystrophy in young children, Down syndrome, and cerebral palsy, prescribe 15-30 mcg every other day.
For hepatitis and cirrhosis of the liver, children should be prescribed 15-30 mcg/day or 100 mcg every other day for 25-40 days.
Contraindication
Hypersensitivity to the components of the drug. erythremia, erythrocytosis. neoplasms, except for cases accompanied by megaloblastic anemia and vitamin B12 deficiency. acute thromboembolic diseases. angina pectoris of high functional class.
Side effects
On the part of the blood: hypercoagulation.
From the nervous system: headache, dizziness, nervous excitement.
Metabolic: acne, bullous rashes, nausea, increased sweating, purine metabolism disorders.
On the part of the immune system: allergic reactions, including skin manifestations, including hyperemia, urticaria, rash, itching, dermatitis, edema, in particular Quincke's edema; respiratory disorders, including suffocation, anaphylactic shock, anaphylactoid reactions.
On the part of the gastrointestinal tract: softening of stools.
General disorders: malaise, fever.
Local reactions, including hyperemia, itching, pain, swelling, induration and necrosis at the injection site.
Special instructions
During the treatment period, it is necessary to monitor peripheral blood parameters: on the 5th-8th day of therapy, determine the reticulocyte content, iron concentration. The number of erythrocytes, hemoglobin and color index must be monitored for 1 month 1-2 times a week, and then 2-4 times a month. Remission is achieved when the number of erythrocytes increases to 4,000,000-4,500,000 / μl, when normal erythrocyte sizes are achieved, anisia and poikilocytosis disappear, and reticulocyte content normalizes after a reticulocyte crisis. After achieving hematological remission, peripheral blood monitoring should be carried out at least once every 4-6 months.
If there is a tendency to develop leukocytosis and erythrocytosis, the dose of the drug should be reduced or treatment should be temporarily suspended.
Cyanocobalamin should not be used with drugs that increase blood clotting.
In people with a tendency to thrombosis and patients with angina pectoris, caution should be exercised during treatment and blood clotting should be monitored.
Use during pregnancy and breastfeeding. Use with caution, under the supervision of a physician, during pregnancy (there is some evidence of the teratogenic effect of vitamin B12 in high doses) and breastfeeding, taking into account the benefit/risk ratio.
Children. The 0.5 mg/ml dosage form should not be used in children under 3 years of age.
Drive only on foot.
Ability to influence the reaction rate when driving vehicles or working with other mechanisms. During treatment, it is necessary to refrain from driving vehicles and engaging in potentially dangerous activities that require increased attention and quick reactions.
Interactions
Aminoglycosides, salicylates, antiepileptic drugs, colchicine, potassium preparations reduce the absorption of the drug and affect its kinetics.
When used simultaneously with kanamycin, neomycin, polymyxins, tetracyclines, the absorption of cyanocobalamin decreases.
Pharmaceutically incompatible with ascorbic acid, heavy metal salts (inactivation of cyanocobalamin), thiamine bromide, pyridoxine, riboflavin (the cobalt ion contained in the cyanocobalamin molecule destroys other vitamins).
Thiamine - the risk of developing allergic reactions caused by thiamine increases.
Chloramphenicol - reduces the hematopoietic response to the drug.
Citamen - with simultaneous use, the effect of Citamen is reduced.
Oral contraceptives - reduce the concentration of cyanocobalamin in the blood.
Overdose
Symptoms: pulmonary edema, congestive heart failure, peripheral vascular thrombosis.
Treatment is symptomatic.
Storage conditions
In the original packaging at a temperature not exceeding 25 °C. Do not freeze.
