Yes, astronauts who spend long periods in orbit can be prophylactically treated with medications for osteoporosis and other conditions that can arise as a result of prolonged exposure to microgravity. It is well known that microgravity can cause a range of negative health effects, including loss of bone density and muscle atrophy. To help combat these effects, astronauts on long-duration missions are typically given a variety of medications and supplements to help maintain their health. This may include medications to prevent osteoporosis, as well as other treatments to help maintain muscle mass and strength. Additionally, astronauts are also required to perform regular exercise and other physical activities while in orbit to help combat the negative effects of microgravity on their bodies.