What's the difference between lovenox (enoxaparin) and heparin?

Lovenox (enoxaparin) vs. heparin: Unfractionated Heparin (UFH) & enoxaparin (lovenox or lmwh) both prevent blood clots by indirectly inhibiting the function of 2 important clotting factors, xa and iia (thrombin). Ufh is very large , while lmwh is smaller. Dosing of UFH is IV or sq every 8-12 hrs, and lmwh sq every 12-24 hrs. Care is needed with lmwh if renal failure. Ufh is more likely to cause hit, a dangerous allergic reaction.