methylcobalamin vitamin b12 injection 1ml Cyanocobalamin 1000 mcg — Mountainside Medical Vitamin B 12 Cyanocobalamin Injection
Description
Discontinue two weeks before surgery or if you experience rapid heartbeat, dizziness, severe headache, or shortness of breath

Q4: Are there side effects

Studies have even shown that up to 49% of patients who have a gastrectomy develop B12 deficiency

One carbon metabolism in pregnancy: impact on maternal, fetal and neonatal health
