Lenalidomide hydrochloride is primarily used in the treatment of multiple myeloma, a type of blood cancer. It is often prescribed in combination with other medications, such as dexamethasone, to enhance its effectiveness. The drug works by modulating the immune system, inhibiting the growth of cancer cells, and promoting their destruction. Additionally, it is utilized in the management of myelodysplastic syndromes (MDS) with a specific genetic abnormality, where it helps reduce the need for blood transfusions by improving red blood cell production. Lenalidomide hydrochloride is also approved for treating mantle cell lymphoma, particularly in patients who have relapsed or are refractory to other treatments. Its ability to target specific pathways in cancer cells makes it a valuable component in various therapeutic regimens.