I Am 46 And Drink Pretty Heavy (vodka, Small Amounts

I am 46 and drink pretty heavy (vodka, small amounts almost all day) I am sick of it as I feel its ruining my life and marriage. My Dr prescribed me Naltrexone so I started looking into it. It has a lot of very good reviews but I noticed some side effects, how common are they as I have a sleeping problem also (probably due to drinking)What do you think? I am seeing my Dr tomorrow to discuss treatment options concerning drinking.