Cyanocobalamin

Pharmacological properties

Vitamin B12 (cyanocobalamin) has a metabolic, hematopoietic effect. in the body (mainly in the liver) turns into a coenzyme form - adenosylcobalamin, or cobamamide, which is an active form of vitamin B12. Cobamamide is part of numerous enzymes, including reductase, which restores folic acid to tetrahydrofolic acid. possesses high biological activity. cobamamide is involved in the transfer of methyl and other monocarbon fragments; therefore, it is necessary for the formation of deoxyribose and dna, creatine, methionine - a donor of methyl groups, in the synthesis of the lipotropic factor - choline, for the conversion of methylmalonic acid into succinic, which is part of myelin, for utilization of propionic acid . cobamamide is necessary for normal hematopoiesis, as it promotes the maturation of red blood cells. participates in the synthesis and accumulation of compounds containing sulfhydryl groups in red blood cells, which increases their tolerance to hemolysis. activates the blood coagulation system, in high doses causes an increase in thromboplastic activity and prothrombin activity. lowers blood cholesterol levels. positively affects the function of the liver and nervous system. increases the ability of tissues to regenerate.

Pharmacokinetics With parenteral administration of vitamin B₁₂ quickly enters the systemic circulation. In the blood, binds to transcobalamin I and II, which transports it to the tissues. It is deposited in the liver. Communication with blood plasma proteins - 90%. Time to reach maximum concentration (T_max) after sc or intramuscular administration is about 1 hour. It is excreted from the liver with bile into the intestine and again absorbed into the blood. T_½ from the liver - 500 days. It is excreted during 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 through the placental barrier.

Indications

Treatment of malignant, posthemorrhagic and iron deficiency anemia, aplastic anemia in children, nutritional anemia caused by toxic substances and drugs associated with vitamin b12 deficiency, regardless of the cause of the deficiency (gastric resection, helminth infestations, malabsorption, pregnancy). polyneuritis, trigeminal neuralgia, sciatica, causalgia, migraine, diabetic neuritis, amyotrophic lateral sclerosis, cerebral palsy, Downs disease, alcohol delirium. used for dystrophy in children, after infectious diseases, with sprue (along with folic acid), liver diseases (hepatitis, cirrhosis, Botkins disease), radiation sickness, psoriasis, herpetiform dermatitis, neurodermatitis, photodermatoses.

Application

The drug is used s / c, v / m, iv, and with lateral funicular myelosis and amyotrophic sclerosis, also intralumbal.

Adults

At₁₂deficient anemia, the drug should be used in doses of 100-200 micrograms (0.1-0.2 mg) every other day until remission is achieved.

When symptoms of funicular myelosis appear and with macrocytic anemia with damage to the nervous system, cyanocobalamin is used in a single dose of 400–500 μg (0.4–0.5 mg) or more. During the 1st week, enter daily, and then at intervals of 5-7 days (at the same time appoint folic acid). In severe cases, inject into the spinal canal, starting with a single dose of 15-30 μg, with each subsequent injection, increase the dose (50; 100; 150; 200 μg). Intralumbal injections should be done every 3 days; a total of 8-10 injections are needed per course. In the period of remission in the absence of the phenomena of funicular myelosis for maintenance therapy, appoint 100 mcg 2 times a month, in the presence of neurological symptoms - 200-400 mcg 2-4 times a month.

In case of amyotrophic lateral sclerosis, encephalomyelitis, neurological diseases with pain, the drug should be administered in increasing doses from 200 to 500 μg per injection (with improvement - 100 μg / day). The course of treatment is 14 days.

In case of peripheral nerve injuries, appoint 200–400 mcg once every 2 days for 40–45 days.

In case of hepatitis and liver cirrhosis, prescribe 15-30 mcg / day or 100 mcg every other day for 25-40 days.

In case of diabetic neuropathy, spru, radiation sickness, enter 60–100 mcg daily for 20–30 days.

With Vitamin B Deficiency₁₂ for treatment - i / m and iv in a dose of 1 mg every day for 1–2 weeks, the maintenance dose is 1–2 mg i / m or iv 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 the treatment.

Children

Enter only s / c.

In case of posthemorrhagic and iron deficiency anemia, appoint 30–100 mcg 2-3 times a week.

In case of aplastic anemia in children, enter 100 mcg before the onset of clinical and hematological improvement.

For nutritional anemia in childhood, prescribe 30 mcg for 15 days.

For dystrophies in young children, Downs disease, and cerebral palsy, 15–30 mcg every other day should be prescribed.

In case of hepatitis and liver cirrhosis, children should be prescribed 15-30 mcg / day or 100 mcg every other day for 25-40 days.

Contraindications

Hypersensitivity to the components of the drug. erythremia, erythrocytosis. neoplasms, except in cases accompanied by megaloblastic anemia and vitamin b12 deficiency. acute thromboembolic diseases. angina of exertion of high functional class.

Side effects

On the part of the blood: hypercoagulation.

From the cardiovascular system: tachycardia, pain in the heart.

From the nervous system: headache, dizziness, nervous excitement.

From the side of metabolism: acne, bullous rash, nausea, increased sweating, impaired purine metabolism.

From the immune system: allergic reactions, including skin manifestations, including hyperemia, urticaria, rash, itching, dermatitis, edema, in particular Quinckes edema; respiratory failure, including an asthma attack, anaphylactic shock, anaphylactoid reactions.

From the gastrointestinal tract: softening feces.

Common disorders: malaise, fever.

Local reactions, including flushing, itching, pain, swelling, tightening, and necrosis at the injection site.

special instructions

During the treatment period, it is necessary to monitor peripheral blood parameters: on the 5-8th day of therapy, determine the content of reticulocytes, the concentration of iron. the number of red blood cells, hemoglobin and the color index must be monitored for 1 month 1-2 times a week, and then - 2-4 times a month. remission is achieved with an increase in the number of red blood cells to 4,000,000–4,500,000 / μl, with the achievement of the normal size of red blood cells, the disappearance of aniso and poikilocytosis, normalization of the content of reticulocytes after a reticulocytic crisis. after hematologic remission is achieved, peripheral blood control should be performed at least 1 time in 4-6 months.

With a tendency to develop leuko- and erythrocytosis, the dose of the drug must be reduced or temporarily suspended.

Do not use cyanocobalamin with drugs that increase blood coagulation.

In patients with a tendency to thrombosis and patients with angina pectoris during treatment, care must be taken to control blood coagulation.

Use during pregnancy and lactation. With caution, under the supervision of a doctor, apply during pregnancy (there are separate data on the teratogenic effect of vitamin B₁₂ in high doses) and breastfeeding, given the benefit / risk ratio.

Children. The dosage form in a dosage of 0.5 mg / ml should not be used in children under the age of 3 years.

Drive only s / c.

The 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 hazardous activities that require increased attention and speed of psychomotor reactions.

Interactions

Aminoglycosides, salicylates, antiepileptic drugs, colchicine, potassium preparations reduce the absorption of the drug, affect its kinetics.

With simultaneous use with kanamycin, neomycin, polymyxins, tetracyclines, the absorption of cyanocobalamin decreases.

It is pharmaceutically incompatible with ascorbic acid, salts of heavy metals (inactivation of cyanocobalamin), thiamine bromide, pyridoxine, riboflavin (the cobalt ion contained in the molecule of cyanocobalamin destroys other vitamins).

Thiamine - the risk of developing allergic reactions caused by thiamine is increased.

Chloramphenicol - reduces the hematopoietic response to the drug.

Cytamene - with simultaneous use, the effect of cytamene is reduced.

Oral contraceptives - reduce the concentration of cyanocobalamin in the blood.

Overdose

Symptoms: pulmonary edema, congestive heart failure, peripheral vascular thrombosis.

The treatment is symptomatic.

Storage conditions

In the original packaging at a temperature not exceeding 25 ° C. do not freeze.