FUE 10 months ago - how long should I take dutasteride for?

Hello, I had a 2000 grafts FUE procedure. Everything its ok, Im in the 10 month after the procedure. Doctor told me that didn't recommend taking the dutasteride pills, instead he prefers to inyect it in my scalp. That way I can avoid secondary effects, however I can't go on regular basis to his clinic. Instead, i'll take the pill, 1 mg per day. How much time should I take it? 1 year? 5? All my life? Is it dangerous for the kidneys or liver to take it for so long? Thanks.