Safe Dose Of Vitamin D

My doctor found that my blood levels of vitamin D were low. She gave me a prescription for 50,000 international units of vitamin D to be taken every two weeks. But I?ve read that the recommended dose is more like 1,000 IU a day, and that more than 4,000 IU a day is unsafe. I have thin bones but not osteoporosis yet. I?m a healthy woman and don?t want to do more harm than good. What?s your advice?