Common side effects include: Injection site reactions mild pain, redness, swelling, or bruising at the injection site, typically resolving within a few days Headache usually transient and manageable with standard analgesia Nausea or dizziness particularly in the initial treatment phase Skin reactions including itching, mild rash, or acneiform eruptions Temporary urine discolouration red or orange urine is harmless and expected Diarrhoea or flushing usually mild and self-limiting In patients with severe megaloblastic anaemia, low potassium levels (hypokalaemia) may occur during initial intensive treatment, but this is uncommon in routine maintenance therapy
So, why B12 shots
Common indications include: Pernicious anaemia an autoimmune condition where the stomach cannot produce intrinsic factor, a protein necessary for B12 absorption [8] [9] Malabsorption disorders including Crohn's disease, coeliac disease, or following gastric surgery Strict vegan or vegetarian diets with confirmed deficiency though high-dose oral B12 may be sufficient if no malabsorption exists Certain medications such as metformin or proton pump inhibitors that may interfere with B12 absorption [9] [10] Neurological symptoms including peripheral neuropathy, memory problems, or balance difficulties related to deficiency Diagnosis should be confirmed through blood tests measuring serum B12 levels, full blood count, folate, and often anti-intrinsic factor antibodies
megaloblastic anemia
Chandy estimates that 1 in 10 people experience this effect