CPV code 33621100 designates Antithrombotic agents in the Common Procurement Vocabulary (CPV 2008), the EU classification used to describe the subject of public contracts.
33621100 is a leaf code — the most specific level of its branch — so it can be used directly as the main CPV code of a contract notice. If it does not quite fit, check the neighbouring codes under 33621000 (Medicinal products for the blood and blood-forming organs).