Your safety is our first priority. Learn more about key medication details, possible side effects, warnings, and other important information about vitamin b12 injection below.
Prescribing Information
Vitamin B12 injection may contain cyanocobalamin, hydroxocobalamin, or another prescribed form of vitamin B12. It may be used for vitamin B12 deficiency, impaired absorption, or another provider-determined medical need. Safety details depend on the exact form and inactive ingredients dispensed.
Black Box Warning
Vitamin B12 injection does not have a boxed warning. Rare but severe allergic reactions, including anaphylaxis, have been reported after parenteral vitamin B12.
Common Side Effects
Common or possible side effects may include:
- Injection-site pain
- Mild diarrhea
- Headache
- Dizziness
- Itching or rash
- Swelling
- Feeling warm
- Nausea
Important Safety Information
Do not use vitamin B12 injection if you have a known sensitivity to cobalt, vitamin B12, or any ingredient in the product. Tell your provider if you have Leber’s disease, kidney disease, severe anemia, low potassium, or a history of serious allergies.
Rapid treatment of severe megaloblastic anemia can rarely cause low potassium and serious heart-rhythm complications. Lab monitoring may be needed during initial replacement. Vitamin B12 can improve blood findings while an untreated folate deficiency or underlying diagnosis remains.
Some multi-dose products contain benzyl alcohol or aluminum, which may be important in infants, pregnancy, kidney impairment, or prolonged high-dose use. Follow the specific pharmacy label.
Seek urgent medical help for difficulty breathing, swelling of the face or throat, fainting, severe weakness, chest symptoms, or an irregular heartbeat.
To report suspected adverse reactions, contact the FDA at 1-800-FDA-1088 or visit www.fda.gov/medwatch.
