What Are the Most Common Methylcobalamin Side Effects?

Methylcobalamin injection is used for peripheral neuropathy. Treatment of megaloblastic anemia caused by lack of vitamin B ₁₂ .

Methylcobalamin injection is used for peripheral neuropathy. Treatment of megaloblastic anemia caused by lack of vitamin B ₁₂ .

Drug Name

Methylcobalamin injection

Drug type

Prescription drugs, medicines for medical workers' injuries

Use classification

Other antianemia drugs

Methylcobalamin injection ingredients

The main ingredients of this product are: methylcobalamin Chemical name: Co - [- (5,6-dimethylbenzimidazolyl)]-Co-methyl-cobalamine
Its structural formula is:

Molecular formula: C ₆₃ H ₉₁ CoN ₁₃ O ₁₄ P
Molecular weight: 1,344.38
Name of excipient: D-mannitol, water for injection

Traits of Methylcobalamin Injection

This agent is a red clear liquid filled in a one-point cut brown ampoule.
pH value: 5.3 7.3
Osmotic pressure ratio: about 1 (ratio to 0.9% physiological saline).

Indications of mecobalamin injection

For peripheral neuropathy.
Treatment of megaloblastic anemia caused by lack of vitamin B ₁₂ .

Methylcobalamin injection specifications

1ml: 0.5mg

Methylcobalamin injection dosage

1. Peripheral neuropathy. Adults usually have 1 ampoule (containing 0.5 mg of methylcobalamin) once a day, 3 times a week, intramuscularly or intravenously. It can be increased or decreased according to age and symptoms.
2. giant red cell anemia
Usually, an adult takes one ampoule (containing methylcobalamin 0.5mg) once a day, three times a week, intramuscularly or intravenously. About two months after the administration, one ampoule can be administered once as a maintenance treatment for 1-3 months.

Adverse reactions of methylcobalamin injection

Of the total 2,872 cases, 13 (0.45%) had side effects. (By the end of the reexamination)
1. Severe side effects (unknown frequency)
Allergic reactions: can cause allergic reactions such as decreased blood pressure and dyspnea. Patients should be closely monitored and if such side effects occur, medication should be discontinued immediately and appropriate measures taken.
2. Other side effects (1) Allergy ^Note : rash (<0.1%), if these side effects occur, the drug should be stopped.

(2) Others: headache, fever (<0.1%); sweating, pain and induration at the site of intramuscular injection (unknown frequency).
Note) If these side effects occur, the medication should be stopped.

Methylcobalamin injection contraindications

Those who are allergic to the ingredients of this product are prohibited

Precautions for mecobalamin injection

1. If it doesn't work after one month of use, you don't need to continue using it for no purpose.
2. Precautions during use (1) When administering
See light is easy to decompose, while using immediately after opening, care should be taken to avoid light.
(2) Intramuscular injection
To avoid the effects on tissues and nerves during intramuscular injection, the following points should be noted:
1) Avoid repeated injections at the same site, and be especially careful of newborns, premature babies, infants, and young children.
2) Be careful to avoid nerves.
3) Note that when the needle is inserted, if there is severe pain or blood reflux, the needle should be pulled out immediately and the injection site changed.
(3) When the ampoule is opened
This product is a one-point fold ampoule. After cutting the ampoule with alcohol cotton, etc.
(4) In order to ensure stable storage quality, the light-shielding protective bag LPE (Light Protect Easy open pack) is used for packaging, and it should be used immediately after taking out from the light-shielding protective bag.

Mecobalamin injection for pregnant and lactating women

Safety for pregnant and lactating women is unknown.

Mecobalamin injection for children

still uncertain.

Mecobalamin injection for the elderly

still uncertain.

Mecobalamin injection drug interactions

still uncertain.

Methylcobalamin injection overdose

It is not clear, and symptomatic support should be given in case of overdose.

Pharmacology and Toxicology of Methylcobalamin Injection

1. Methylcobalamin is an endogenous coenzyme B ₁₂ .
As a coenzyme of methionine synthase, it plays an important role in the transmethylation reaction of methionine from homocysteine.
2. Methylcobalamin is easily transferred to the organelles of nerve cells, thereby promoting the synthesis of nucleic acids and proteins.
Methylcobalamin is easier to transfer into organelles of nerve cells in rats than cyanocobalamin. In experiments on brain cells and spinal nerve cells in mice, it participates in the process of synthesizing thymidine from deoxyuracil nucleoside, promoting the utilization of folic acid and the metabolism of nucleic acids. Moreover, mecobalamin can promote rat nucleic acid and protein synthesis more than cobamide.
3. Promote axonal transport and axonal regeneration In the sciatic nerve cells of a rat model of diabetes caused by streptozotocin, normalization of axonal structural protein delivery can be achieved. For neurological disorders caused by doxorubicin, acrylamide, and vincristine (rats, rabbits) and axonal deformed rat models, neuropathy of naturally occurring diabetic rats can inhibit degeneration in neuropathology and electrophysiology The emergence of nerves.
4. Promote the formation of myelin sheath (phospholipid synthesis)
Compared with adenosylcobalamin, it can promote the synthesis of phosphatidylcholine, the main structure of myelin sheath, thereby improving the formation of myelin sheath (rat).
5. Restoration of neural bond transmission delay and reduction of neurotransmitting substances In the experiment of contusion and sciatic nerve, due to the increase of nerve fiber excitement, the terminal potential induction is restored (rat). In addition, the low acetylcholine content in the brain of rats fed choline deficient bait can be normalized.
6. Promote the maturation and division of normal red blood cells, improve the anemia. The lack of vitamin B ₁₂ may lead to giant red blood cell anemia. This medicine promotes the synthesis of nucleic acids in the bone marrow and the maturation, division and increase of red blood cells. The generation. This medicine can quickly restore the erythrocyte count, hemoglobin, and hematocrit value of rats that were reduced due to B ₁₂ deficiency.

Pharmacokinetics of Methylcobalamin Injection

1. One-time administration
The time (t _max ) to reach the highest concentration of total vitamin B ₁₂ (abbreviated as B ₁₂ ) in serum was given by intramuscular injection and intravenous injection of CH ₃ -B ₁₂ 500 g to 12 healthy people. The intramuscular injection was 0.9 ± 0.1 hours. Immediately to 3 minutes after the intravenous injection, the increase in the total B ₁₂ concentration in the highest serum (excluding the endogenous serum total B ₁₂ ) (C _max ) was 22.4 ng / ml and 85.0 ng / ml, respectively.
In addition, the area under the time curve (AUC) of the total B ₁₂ concentration in the serum calculated from the increase of the measured value at the end of 144 hours after administration was 204.1hr · ng / ml and 358.6hr for intramuscular injection and intravenous injection, respectively. · Ng / ml, on the other hand, showed a substantially equal increase in the combined saturation rate in both dose groups by 144 hours after the dose.

Time after administration (concentration of total B ₁₂ in serum after a single injection of 500 g of mecobalamin)
Pharmacokinetic parameters of a single dose of mecobalamin 500 g

2. Continuous administration
Intravenous injection of 500 g of CH ₃ -B ₁₂ into healthy people for 10 days. Before each administration, the total B ₁₂ concentration (C _min ) in the serum increased continuously with the increase of the administration days. Two days after administration and the initial administration The value in the next 24 hours (3.9 ± 1.2ng / ml) is about 1.4 times (5.3 ± 1.8ng / ml), and about 1.7 times (6.8 ± 1.5ng / ml) on the third day Concentrations last until the last dose.

Methylcobalamin injection storage

Store at room temperature and keep in a light-proof protective bag. (If the ampoule is exposed, it will be decomposed and the content will be reduced)

Methylcobalamin injection packaging

Brown ampoule. 4 ampoules / box, 10 ampoules / box.

Shelf life of mecobalamin injection

36 months.

Methylcobalamin injection standard

Import drug registration standard JX20000562 ^[1]