Different dosage forms of methylcobalamin have the same efficacy and can generally be replaced, but the specifications of the drug may vary, so the specific use of dosage, should be in accordance with medical advice. Mecobalamin is a common clinical drug, mainly used in the treatment of peripheral neuropathy. The drug belongs to the endogenous coenzyme B12, which mainly acts on the cyclic process of one-carbon units in the body. The drug has methylcobalamin tablets, methylcobalamin capsules and other dosage forms, but the efficacy of the drug is the same, generally can be changed under the guidance of the physician to take. It should be noted that the possible adverse reactions to methylcobalamin include nausea, loss of appetite, vomiting, diarrhea, skin rash and other symptoms. It is also contraindicated in people with a history of allergy to the product, and is not recommended for long-term use in large quantities by people who are undergoing the effects associated with mercury and mercury compounds. The use of the drug needs to be carried out under the supervision of a doctor.