I Am A 69 Yr Old Woman That Has Had

I am a 69 yr old woman that has had Livedoid Vasculopathy for over 15 years. I have been taking Pentoxifylline three times a day and Enoxaparin 30 injections twice a day. I am now on Medicare and the Part D prescription plan has Enoxaparin in Tier 4 which costs $225 per month. I have been reading articles to see what I can use that will be cheaper. The formulary shows Heparin in Tier 1 but I don't know if this would be good for me.