The following multitiered style for creating nonproprietary names for interferons was adopted by the USAN Council: The word interferon is the first element in the name. Interferon is defined as the class name for a family of species-specific proteins (or glycoproteins) produced according to information encoded by species of interferon genes and which exert complex antineoplastic, antiviral and immunomodulating effects. The 3 main forms of interferon used in therapy are interferon alfa (formerly leukocyte or lymphoblastoid interferon), interferon beta (formerly fibroblast interferon), and interferon gamma (formerly immune interferon).
The appropriate Greek letter (spelled out) is the second word of the name: alfa, beta, gamma.
An appropriate Arabic numeral and letter are appended to the Greek letter by a hyphen (with no spaces) to delineate subcategories. The numbers conform to the recommendation of the Interferon Nomenclature Committee. The lowercase letter is assigned by the drug nomenclature agencies to differentiate one manufacturer's interferon from another's. Examples of pure interferon substances are:
- interferon alfa-2a
- interferon alfa-2b
- interferon beta-1a
- interferon beta-1b
- interferon gamma-1a
For mixtures of naturally occurring interferons, the lower case letter "n" precedes the number. Examples of names of mixtures of interferons obtained from a natural source, whether the exact percentage of a mixture is known or not, are:
- interferon alfa-n1
- interferon alfa-n2