Lenalidomide is a medication primarily used to treat certain types of blood cancers, including multiple myeloma and myelodysplastic syndromes. It works by modulating the immune system and inhibiting the growth of cancer cells, helping to improve patient outcomes. This drug is often prescribed in combination with other treatments and is taken orally. Patients using lenalidomide may experience side effects such as fatigue, low blood cell counts, and an increased risk of infections. Regular monitoring by healthcare professionals is essential to manage these potential risks effectively.