can b12 injections cause fever What Happens When You're Allergic to Vitamin Vitamin B12 Injections: Hot Shots?
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Injections that contain a prescription medication, however, should have more specific dosage requirements

They get both through the blood supply
Therefore, some experts recommend testing for post-immunization Hepatitis B antibody titers in patients with chronic liver disease due to their risk of severe infection

Please note: this article focuses on the benefits of adding B12 vitamins as supportive care to the main FIP treatment