Understanding Medicare drug coverage is essential. Here's a brief overview: Part A covers medications during hospital stays or skilled nursing facilities. Part B includes drugs supplied by your healthcare provider or at Medicare and B12 injections: Are They Covered? Medicare Options The Difference in Medicare A and B Cyanocobalamin Medicare Coverage and Co Pay Details GoodRx Vitamin B12 Medicare Coverage and Co Pay Details GoodRx Does Your Medicare Plan Cover B12 Shots?