Vitamin B-12 Injections Vitamin B-12 is required for proper red blood cell formation, neurological function, and DNA synthesis. It may also increase energy levels and promote a strong immune system. Some individuals, especially older adults and those with pernicious anemia have difficulty absorbing vitamin B-12. Several studies confirm that up to 15% of adults are deficient in vitamin B12. Common medications such as omeprazole (Prilosec®), lansoprazole (Prevacid®), cimetidine (Tagamet®), famotidine (Pepcid®), ranitidine (Zantac®), and Metformin® may decrease absorption of vitamin B-12. All vitamin B-12 injections at Passport Health are given by Registered Nurses (RNs) with extensive vaccination experience. With flexible scheduling hours and never a wait more than 5 minutes, patients find monthly injections an easy option at Passport Health.