United States Adopted Names (USAN) Program
Report to ACS Nomenclature Committee
March 24, 2007
The USAN Council works to select simple and useful nonproprietary names for drugs and certain other agents (e.g., contact lens polymers, diagnostics, carriers, gene therapies, cell therapies). It cooperates with the World Health Organization (WHO) International Nonproprietary Names (INN) Programme and national nomenclature groups to standardize pharmaceutical nomenclature and establish rules governing the classification of new substances.
In selecting a nonproprietary (generic) name for a substance, the principal concerns of the USAN Council are patient safety, usefulness to healthcare practitioners, ease of pronunciation, the usefulness of a name internationally, and the absence of trade name conflicts.
USAN Council and USAN Review Board
The USAN Council has five members, one from each of the sponsoring organizations of the American Medical Association (AMA), American Pharmacists Association (APhA) and the Unites States Pharmacopeial Convention, Inc. (USP); one member from the United States Food and Drug Administration (FDA), and a member-at-large. One member is nominated to the USAN Council annually by each sponsoring organization. The FDA nominates one liason member annually and the member-at-large is selected by the sponsoring organizations. The five nominess to the Council must be approved annually by the boards of trustees of the three sponsoring organizations. Individual members may serve up to ten consecutive years.
In its first year, there was no external means of settling disputes over drug name selection between the USAN Council and pharmaceutical firms. The gap was filled by establishing a formal mechanism for dispute resolution and the USAN Review Board.
How USANs are assigned
A USAN should be requested after clinical trials have begun, when there is some expectation that the substance to be named could be marketed as an FDA-approved product. For substances that will be marketed for human use, an Investigational New Drug number is required before a manufacturer can obtain a USAN. Adoption of the USAN must be complete by the time the New Drug Application is filed. In practice, most pharmaceutical companies request a USAN when the substance is in Phase I or Phase II clinical trials.
The USAN is adopted after three-way negotiations involving the manufacturer, the USAN Council and the WHO-INN Exert Group. All parties must agree to accept a name before it can be adopted as a USAN, and the name must be unanimously acceptable to the USAN Council.
When a submission is received, a USAN Program staff member, often referred to as a "negotiator," reviews the application and the chemical, pharmacological, clinical and other information submitted to support it. The negotiator prepares a ballot with suggested names and an analysis of the manufacturer's submission, which is forwarded to the USAN Council by e-mail. The USAN Council selects a name via correspondence balloting, or at its bi-annual meetings, and this name is forwarded to the manufacturer for approval. Selecting a name can require two or more rounds of balloting if the manufacturer's initial suggestions are not accepted by the USAN Council. Once the name is accepted by the USAN Council and the manufacturer, it is forwarded to the WHO-INN Secretariat's office for additional review and clearance.
A manufacturer may use a USAN only after receiving an adoption statement. This document is issued on the last Wednesday of the month, after all parties accept a name. Pharmaceutical and biotech firms typically use the name in presentations at meetings, abstracts, publications, regulatory filings, advertising and promotional materials, and in the product labeling information. Physicians prescribing a drug use the USAN, most often after generic equivalents become available, as well as nurses and pharmacists who dispense or administer it. Because the common physician practice to prescribe drugs by trade names can lead to medication errors and because trade names are not consistent worldwide, there have been some recent education and advocacy efforts to encourage physicians to always use generic names when prescribing.
International cooperation
Most drug manufacturers seeking a USAN are multinational companies with subsidiaries in various parts of the world. Therefore, pharmaceutical firms, the various nomenclature committees, and the medical community in general benefit when a single, global name is established for each substance. The USAN Council works with its counterparts in the WHO-INN Programme to ensure that a single name can be used worldwide.
The assignment of a single, global name also benefits patient safety. It ensures, for example, that Americans with a US prescription who obtain medications outside the US or though online pharmacies will receive the same substance prescribed by their physician. When pharmaceutical trade names vary from country to country, the USAN/INN is the only name that remains consistent worldwide.
The INN Secretariat holds two consultative sessions each year in Geneva. The current INN Expert Group has ten members representing national nomenclature committees, national health/science agencies, or scientists from "emerging" countries.
Nomenclature rules
A name chosen as a USAN must conform to the USAN Program's established general principles and specific nomenclature rules under Rules for Coining Names. To avoid trademark conflicts, and to avoid confusion of drug names in the clinical setting, the adopted name should be reasonably free from conflict with other generic names and trade names.
Several decades ago, USANs were derived by condensing the systematic chemical name of the substance into a shorter name that was eaier for healthcare professionals to write, say and remember. However, this practice led to the creation of many similar names, and healthcare providers too often confused names that looked or sounded similar. Because changing the names of established drugs would confuse healthcare providers further, older drugs still have names based on this system.
Current nomenclature practices rely on the use of stems, suffixes that classify drugs according to their chemical structure, indication or mechanism of action. For example, antiviral substances receive a -vir stem; cyclooxygenase-2 inhibitors are assigned to the -coxib stem; and peptides are names with a -tide stem.
To differentiate members of the same class, a "fantasy" prefix with no meaning is used. Several rules affect the choice of prefix. Prefixes cannot contain specific letters or letter combinations (e.g., i, y, k, th, ph) that lead to ambiguous pronunciations, or pronunciation difficulties in languages other than English. Prefixes cannot refer to or be derived from anatomy, targets, a site of action, the drug's trade name, the innovator company's name, the manufacturer code, dosage forms, or chemical moieties within the compound. They cannot imply that a drug is new, better or stronger (bene-, fort-, nova-).
Occasionally, the USAN Council may use infixes to differentiate among subgroups of the same class of drugs. Thus the -pultide stem/infix combination is used for peptides that are prescribed as pulmonary surfactants. A complete list of USAN stems and infixes is available online for use in applying.
Biologics (i.e., monoclonal antibodies, gene therapies, cell therapies and some proteins) are named according to specific nomenclature schemes for these substances. The monoclonal antibody nomenclature scheme is a well-established example. All antibodies receive a -mab suffix; an infix to indicate the source (-xi- for chimeric, -zu- for humanized, -u- for fully human), and an infix for the disease or target (-li(m) for immunomodulators, -tu(m) for antitumor targets), and a fantasy prefix.
USAN publications
The Newly Approved USAN section of the web site lists newly adopted USAN released for publication. Recent changes include conversion of adoption statements to pdf files and posting downloadable applications in MS Word format. In addition, the USAN Council has reviewed policies regarding the use of two-word names for salts and esters. A document that explains two-word names and an updated list of USAN designations for radicals, salts, counterions, coprecipitated solvent molecules, and ester groups, and other moieties were posted. New nomenclature schemes for gene and cell therapies have also been posted.
When adoption statements are published on the USAN Web site, they are also sent to the USP and Chemical Abstracts Service. The USP publishes the USP Dictionary of USAN and International Drug Names annually.
USAN staff has also begun publishing a quarterly newsletter to provide additional information to manufacturers and to answer frequently asked questions. Recent topics include requests for new stems, trademarks searches and two-word names. Future newsletters will focus on the standardized pronunciation rules.
Content provided by: USAN