Which treatment is effective for pernicious anemia?

The treatment that is effective for pernicious anemia is hydroxocobalamin administered intramuscularly. Pernicious anemia is a type of macrocytic anemia that occurs due to the body's inability to absorb vitamin B12, which is essential for red blood cell production. This deficiency is often due to a lack of intrinsic factor, a protein produced in the stomach that is necessary for the absorption of vitamin B12 from the diet.

Hydroxocobalamin is a form of vitamin B12 that is typically given via injection, particularly intramuscularly, to bypass the gastrointestinal absorption issue that individuals with pernicious anemia experience. This route of administration allows for direct entry of vitamin B12 into the bloodstream, effectively replenishing the body's stores and alleviating the symptoms associated with the deficiency.

Other options, while they might be used for various other medical conditions, do not address vitamin B12 deficiencies or pernicious anemia specifically. Therefore, hydroxocobalamin IM is the appropriate and effective treatment for managing this condition.