Medications know to cause bone marrow suppression (e.g., myelosuppressive antineoplastic agents) may result in a blunted or impeded response to methylcobalamin, vitamin B12 therapy
Most patients feel increased energy within 2472 hours of their first injection
B12 injections solve this problem quickly
In this situation, it can be challenging to demonstrate B12 deficiency even when there are typical symptoms (including neuropathy-like paraesthesia and numbness), as serum B12 concentrations may be just within, or sometimes above, the normal range due to the oral supplementation
Regular follow-up consultations are recommended to monitor progress and make any necessary adjustments
It also helps to correct severe deficiencies very quickly (if the deficiency is not based on genetic abnormalities which may require a specific form(s) of B12)