A soluble compound for preventing or reducing blood coagulation comprising an antithrombotic agent and a membrane binding element, wherein the antithrombotic agent has a weight of less than about 5,000 daltons. Also disclosed is a soluble compound for preventing or reducing blood coagulation comprising an anticoagulant joined to a membrane binding element via a joining element, wherein the joining element between the anticoagulant and the membrane binding element is less than about 10,000 daltons in weight. These compounds can be used in therapy and, in particular, in preventing or reducing blood coagulation. As a result, a method of treatment is provided comprising administering an effective amount of the compounds to a subject to prevent or reduce blood coagulation as well as a method of perfusing an organ, tissue or cell comprising contacting the compounds with the organ, tissue or cell to prevent or reduce blood coagulation. Also disclosed is an organ, tissue or cell which has been perfused with the compounds.