PZN, which stands for "Pharmazentralnummer" in German, is a unique identifier for pharmaceutical products. However, there are several synonyms that are used in different countries to refer to the same thing. In the United States, the National Drug Code (NDC) serves as a similar identifier for drugs. In Europe, the European Article Number (EAN) or International Article Number (IAN) can be used. In the United Kingdom, the Article Number (AN) or the British National Formulary (BNF) number is often used. Regardless of the synonym, these numbers allow healthcare providers and patients to identify and track specific pharmaceutical products for safety and efficacy purposes.