An up-to-date and well-established classification resource can assist stakeholders in managing their drug formulary more efficiently. USP, a non-profit organization develops public compendial quality standards and solutions, including two drug classification systems: the Medicare Model Guidelines (MMG) for Part D plans and USP Drug Classification (USP DC) for non-part D plans.
USP Drug Classification
The USP Drug Classification (USP DC) is an independent hierarchical therapeutic drug classification system designed to assist with formulary support outside of Medicare Part D, including non-Medicare and essential health benefits (EHB) drugs. The goal of the USP Healthcare Safety & Quality Expert Committee is to create a comprehensive classification system for use in drug formulary development or review in non-acute or outpatient care settings. This tool can provide guidance to support the design and comparison of balanced formularies.
Important Updates
- January 15, 2025 – USP DC was 2025 published.
- October 1 to October 31, 2024 – USP DC 2025 Draft was available for Public Comment.
For additional information, please contact uspdc@usp.org
Please Note: The USP DC is not designed for CMS Part D Formulary Submissions. Part D Stakeholders should use the USP Medicare Model Guidelines (USP MMG)
Formulary Solutions
USP DC 2025
The USP Drug Classification 2025 (USP DC 2025) was published on January 15, 2025, and can be downloaded by completing a short form. The freely accessible version of the USP DC includes a list of FDA-approved example drugs outside of Medicare Part D, organized by categories and classes.
USP Drug Classification PLUS
On December 15, 2023, the drug classification file that includes coded identifiers (previously known as the Drug Alignment File) was introduced as part of a new, subscription-based offering: USP Drug Classification PLUS. The USP DC PLUS includes additional information to support your classification review of newly approved FDA drugs used in outpatient settings.
| USP Drug Classification 2025 | USP Drug Classification PLUS | |||
|---|---|---|---|---|
| Access | Free | Subscription | ||
| Requirements | Fill out download form Completion (e.g., name, e-mail, intended use) | USP Access Point account (e.g., Tax ID, Customer ID) | ||
| Content | Four-tiered list of FDA-approved example drugs outside of Medicare Part-D that are organized by Categories and Classes | All the USP DC free content PLUS alignment file that provides:
| ||
| Tier 1 | USP DC Category | Over 50 categories | ||
| Tier 2 | USP DC Class | Over 175 classes | ||
| Tier 3 | Pharmacotherapeutic Group (informational) | Over 207 groups | ||
| Tier 4 | Example Drug | Over 2,055 drugs | ||
| Format | Microsoft Excel File | Available in two formats:
| ||
For additional information, please visit the USP DC PLUS to learn more.
Proposed Uses
The USP DC is intended for use by any stakeholder interested in a classification of drugs for use in formulary development or review. The classification system can have many uses for formulary support including but not limited to:
- Building and mapping formularies
- Reviewing formulary adequacy for a minimum baseline of drugs
- Identifying drugs in a particular pharmacologic grouping
- Reviewing formularies and comparing formulary design and benefits
The USP DC may be helpful as part of a comprehensive formulary review process, but is not intended to replace the final review provided by the local pharmacy and therapeutics (P&T) committees. Moreover, the USP DC is not intended for review of medical benefit drug coverage, since the USP DC does not include all drugs administered in a clinical setting.
Origins of Development
USP has a long history of creating classification systems for the purpose of formulary review. USP has developed and updated the USP Medicare Model Guidelines (MMG) since 2004, under the Medicare Prescription Drug Improvement and Modernization Act (2003), Section 1860D-4(b)(3)(C)(ii). This section includes a requirement that Part D plans cover at least two drugs in each USP Category and Class.
The USP DC was created by a USP Expert Panel during the 2015-2020 cycle formed under the Healthcare Safety and Quality (HSQ) Expert Committee. The USP DC was initiated by stakeholder feedback to meet evolving public health needs. Over the past ten years, the USP MMG has been adopted in other health policy settings outside of its intended Medicare utilization. USP has received public comments and stakeholder feedback that identified the need to create an independent classification system to provide a more comprehensive inclusion of outpatient drugs, more frequent revisions, and more detailed mapping tools for implementation.
The USP DC is a classification system separate from the Medicare Model Guidelines (MMG) and is not endorsed or funded by the CMS.
Comparison to the MMG
A comparison of the USP DC to the MMG:
| USP Medicare Model Guidelines (USP MMG) | USP Drug Classification (USP DC) | |
| Current Publication Version | USP MMG v9.0 | USP DC 2025 |
| Publication Date | September 29, 2023 | January 15, 2025 |
| Revision Cycle | Every 3 years* | Every 1 year |
| Developed under the Medicare Modernization Act to support Medicare Part D requirements | √ | N/A |
Provides Drug Examples | Part D eligible drugs only | Common US outpatient drugs |
| Developed through USP Expert Volunteers, Stakeholder Engagement, and Public Comment Processes | √ | √ |
Utilizes USP Guiding Principles for establishing Categories and Classes | √ | √ |
| Implementation Tools: Mapping to RxNorm | CMS FRF- MMG Alignment File (triennial) | N/A |
| Stakeholder Focus in Public Comment | Medicare Stakeholders | All Stakeholders |
*Upon request of Centers for Medicare and Medicaid Services (CMS)
Organization of USP DC 2025
The USP DC 2025 contains a listing of single entity drug products, combination drug products, and vaccines.
Below is a definition of the data elements in the USP Drug Classification.
| Data Element | USP DC 2025 | Definition |
|---|---|---|
| USP Category | 50 Categories | A USP Category is the broadest classification of the USP Drug Classification system and provides a high level formulary structure. |
| USP Class | 175 Classes | A USP Class is a more granular classification, occurring within a specific USP Category in the USP Drug Classification system. |
| Pharmacotherapeutic Group | 207 Pharmacotherapeutic Groups | An attribute of a drug, providing additional informational groupings on drugs based on therapeutic use or pharmacology. The pharmacotherapeutic groups are currently under development and not intended to be used for review of formulary adequacy for a minimum baseline of drugs. |
| Example Drug | 2055 Example Drugs | An example drug is the active ingredient in a drug product (not an inactive ingredient, such as an excipient). An example drug includes the active ingredient of a drug product but not its strength or dosage form. |
| Filter by Type | Users can filter only this column to select/view any of the following data elements: USP Category, USP Class, USP Pharmacotherapeutic group, a combination drug product, or a single entity drug product. (Cat)- USP Category |
USP DC Development Process
The USP DC is developed through USP’s independent, science-based, expert-led process that relies on stakeholder input, including formal public comment periods.
USP Drug Classification Expert Volunteers
For the 2020-2025 cycle, a new USP Drug Classification Subcommittee was formed to continue the work from the previous cycle. The Subcommittee consists of academicians, practitioners, formulary experts, patient advocates, and clinicians. This Subcommittee advises the Healthcare Safety and Quality Expert Committee on issues discovered during the annual revision processes that are relevant to developing, implementing, and revising the USP DC.
Drug Identification
Drugs included in the USP DC 2025 are identified through various sources including:
- Drugs@FDA
- RxNorm Current Prescribable Content
- Purple book: Lists of Licensed Biological Products
- Stakeholder feedback
- Publicly available prescription formularies
Guiding Principles
As with the 2024 version, the USP Drug Classification Subcommittee used the following guiding principles to inform their development of the USP DC 2025.
Types of Example Drugs Listed
The Subcommittee's goal was to include a comprehensive list of drugs used in non-acute and outpatient care settings. This includes prescription medications patients receive from community pharmacies, specialty pharmacies, skilled nursing facilities, and infusion centers. At this time, the Subcommittee has excluded from the USP DC 2025 most medications used in hospital-only settings, over-the-counter drugs, and medications that are not FDA-approved. Some listed drugs may have over-the-counter products as well as prescription-only dosage forms. For example, diphenhydramine is available as an over-the-counter product for oral dosage forms and prescription-only for injectable dosage forms.
Approach to creating Categories and Classes
The USP Drug Classification retains the guiding principle of the Medicare Model Guidelines (MMG), to strike a balance of helping to assure patient access to the drugs that patients need with the flexibility that health plans require in offering an affordable and effective benefit.
When creating the categories and classes, there was careful consideration to minimize the creation of categories or classes with less than three drug examples.
Approach to Placement of Example Drugs
Through the lens of equity and diversity, when appropriate, the USP DC will consider issues such as genomic status, medical conditions, race, ethnicity, disability, sexual orientation, or gender identity in drug classification.
The USP DC utilizes pharmacotherapeutic evidence within the context of FDA-approved indications for placing example drugs. Many of these example drugs may have established indications and uses outside of the United States and qualities of other drug classes (pharmacology). A drug in the associated list may appear in more than one USP Category or USP Class if there is a scientifically valid and clinically meaningful patient care use.
Combination products are placed in USP groupings distinguished by "Combinations" or "Other" under the respective USP Category. If the combination product includes an active ingredient that improves absorption or efficacy of another active ingredient, the placement will be based on the active ingredient that contributes to therapy and not the augmenting agent. For example, Amoxicillin/Clavulanate Potassium is placed in USP Class "Beta-lactam, Penicillins" based on amoxicillin and not clavulanate potassium, an augmenting agent that enhances the spectrum of activity of amoxicillin by inhibiting beta-lactamases that inactivate amoxicillin.
Specific dosage forms/formulations/delivery systems are generally not listed but may be included in the associated list if there is a valid and clinically meaningful patient care issue addressed by these more specific factors.
Versions of USP Drug Classification
USP Drug Classification 2025
(published January 15, 2025)
USP Drug Classification 2024
(published December 15, 2023)
USP Drug Classification 2023
(published December 16, 2022)
USP Drug Classification 2022
(published December 17, 2021)
USP Drug Classification 2021
(published December 18, 2020)