I think finasteride and alcohol together can screw with your hormones, and create side effects. I've seen many people report this, and its also happened to me. Mind you I've since lowered my dose and it seems I can tolerate drinking better now.
i drink heavily at least twice a week sometimes more and take finasteride once a day and have noticed absolutely nothing. i highly doubt it has any effect.
I drank quite heavily in the past and had no problems. I don't think alcohol has any affect on the metabolization of finasteride. Probably the reason for sides is that alcohol lowers testosterone and being on finasteride probably makes one more sensitive to this.