Like physician assistants, nurse practitioners have received a master’s degree in a field of medicine. Nurse practitioners must also have an active RN (Registered Nurse) license. Physician assistants and nurse practitioners have different requirements for the number of hours of clinical experience required to complete the program. As their name suggests, physician assistants often work with physicians, whereas nurse practitioners can practice medicine without working with a physician. Nurse practitioners serve a more specialized role than is required of physician assistants.