Neomycin, colchicine, para-aminosalicylic acid, or excessive alcohol intake longer than two weeks may cause malabsorption of vitamin B12. Chloramphenicol and other drugs having bone marrow suppressant properties may cause a lack of therapeutic response to vitamin B12
They may also cause (10), (6): Stomach problems like diarrhea Urinary issues Fatigue Nausea Headache Body pain Allergic reactions (itching, hives i A skin rash caused by allergic reactions to stress and certain foods, medications, or other substances and may lead to bumps and itching
Inject the total volume of Vitamin B12 under the skin
Additionally, the injections tend to be costlier, for something you will get in a drop form, so why pay more for the same thing you can get, for a fraction of the price
The arm or thigh injection sites are chosen for comfort and accessibility