The reported adverse reactions following parenteral administration of vitamin B12 include: Generalized : Anaphylaxis and death Cardiovascular : Pulmonary edema and congestive cardiac/heart failure during early treatment
What can go wrong Pain, swelling and a small lump The most common outcome of a rushed or badly angled injection is local irritation: soreness, redness, a small firm lump or a bruise
(2) Cox HD, Smeal SJ, Hughes CM, Cox JE, Eichner D
If you are taking the injections for a specific medical reason, for instance, as part of recovery from surgery or illness, your doctor will monitor objective markers
The choice affects how often and how much you get