Tacrolimus is a medication primarily used to prevent organ rejection in transplant patients. It works by suppressing the immune system, which helps the body accept the new organ. Tacrolimus is often prescribed after kidney, liver, or heart transplants and is available in oral and topical forms. In addition to its use in transplants, Tacrolimus is also used to treat certain skin conditions, such as eczema. When applied topically, it helps reduce inflammation and itching. Patients using Tacrolimus should be monitored for potential side effects, including kidney issues and increased risk of infections.