A synthetic form of low-molecular-weight heparin has been created that can be reversed in cases of overdose and would be safer for patients with poor kidney function. Heparin is an anticoagulant, and is most commonly extracted from pig intestines in two forms: unfractionated heparin, which is commonly used in procedures such as dialysis, and a more-refined low-molecular-weight (LMW) heparin, which is used around the world for preventing dangerous blood clots.