USP Drug Classification

The USP Drug Classification (USP DC) is an independent drug classification system developed in response to stakeholder input that it would be helpful to have a classification system beyond the Medicare Model Guidelines (MMG), to assist with formulary support outside of Medicare Part D. The Healthcare Quality & Safety Expert Committee goal is to create a comprehensive classification system for use in drug formulary development or review in non-acute or outpatient care settings. This tool has the potential to provide guidance towards the design and comparison of balanced formularies.

Important Updates

  • October 5 - October 30, 2020: USP DC 2021 will be posted for Public Comment
  • December 18, 2020: USP DC 2021 will be published
  • December 20, 2019: USP DC 2020 Published

Important: The USP DC is not designed for CMS Part D Formulary Submissions. Part D Stakeholders should use the USP Medicare Model Guidelines (USP MMG)

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. The latter has allowed interested stakeholders to review formularies and compare formulary design and benefits

USP DC is intended to be part of a comprehensive formulary review process and not intended to replace the final review provided by the local pharmacy and therapeutics (P&T) committees. Moreover, USP DC is not intended for review of medical benefit drug coverage since 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 since 2004, under the Medicare Prescription Drug Improvement and Modernization Act (2003), Section 1860D-4(b)(3)(C)(ii). This section included a requirement that Part D plans cover at least 2 two drugs in each USP Category and Class.

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. Through this extension of use, public comment and stakeholder feedback has identified the need to create an independent classification system that can 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 MMG and is not endorsed or funded by the Centers for Medicare & Medicaid Services.

Comparison to the Medicare Model Guidelines (MMG)

A comparison of the USP Drug Classification System (USP DC) to the Medicare Model Guidelines (MMG)

  USP Medicare Model Guidelines (USP MMG) USP Drug Classification (USP DC)
Developed under the Medicare Modernization Act to support Medicare Part D requirements

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) USP DC- RxNorm Alignment File (annual)
Stakeholder Focus in Public Comment Medicare Stakeholders All Stakeholders 
Revision Cycle Triennial* Annual
Publication Version USP MMG v8.0- Pending publication
February 1, 2020
USP DC 2020
Intended Publication Date

February 1, 2020

December 20, 2019

 *Upon request of Centers for Medicare and Medicaid Services (CMS) 

Organization of USP DC 2020

The USP DC 2020 contains a listing of unique active pharmaceutical ingredients including single entity drug products, combination drug products, and vaccines.  The previous 2019 version was organized into two lists: Single Entity and Combination list, and Vaccine list.  To improve readability, the two lists were combined to include all the example drugs.

Below is a definition of the data elements on the USP Drug Classification.

Data Element Definition
USP Category A USP Category is the broadest classification of the USP Drug Classification system and provides a high level formulary structure. In USP DC 2020 there are 51 USP categories. 
USP Class A USP Class is a more granular classification, occurring within a specific USP Category in the USP Drug Classification system. In USP DC 2020 there are 171 USP classes.
Pharmacotherapeutic Group

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. In USP DC 2020 there are 122 pharmacotherapeutic groups.

Example Drug An example drug is an active pharmaceutical ingredient (API) in a drug product. This is in contrast to inactive ingredients such as excipients. An example drug includes the API of a drug product but not its strength or dosage form. In USP DC 2020, there are 1737 example drug placements.
Combination Drug Product

A flag to indicate if a drug product is a combination drug product (yes/no) or if a row contains a USP Category or USP Class name (Cat/Class).  Users can filter this column to choose to select/view any of the following data elements: USP Category, USP Class, combination drug product or single entity drug product.

Values are:
Yes: The drug contains more than 1 API
No: The drug contains only 1 API
(Cat)- USP Category
(Class)- USP Class
(PG)- USP Pharmacotherapeutic Group


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 and other in-person events.

USP Drug Classification Expert Panel

The USP Drug Classification Expert Panel was created for the 2015-2020 cycle under the Healthcare Quality & Safety Expert Committee. This Expert Panel of academicians, practitioners, formulary experts, patient advocates, and clinicians began their work on developing the USP DC in March of 2016. The Expert Panel advises the Healthcare Quality & Safety Expert Committee on issues discovered during the annual revision processes that are relevant to developing, implementing, and revising the USP DC.

Drug Identification and Drug Summary Files

Drugs included in the USP DC 2020 are identified through various sources including Drugs@FDA, RxNorm Current Prescribable Content, Purple book: Lists of Licensed Biological Products, stakeholder feedback, and publicly available prescription formularies.

The Drug Summary Files were developed specifically for the Expert Panel by USP staff with key drug information that would inform about placement of drugs in USP categories and classes. The Drug Summary Files include FDA regulatory information, approved FDA labeling, and FDA Established Pharmacologic Class. When applicable, primary peer-reviewed scientific articles and treatment guidelines were also included in the Drug Summary Files.

Public Comment Process

The USP DC 2020 Proposed Draft was made available via the website for public comment from October 14th until November 15th, 2019. Stakeholders had the opportunity to provide comments via email, public comment form, stakeholder 1:1 consultations, and open microphone web meetings.

Fifteen stakeholders provided comments and over 40 requests were evaluated for incorporation in the draft. Commenters include drug manufacturers, regulators, health plans/PBMs, academia, and patient advocacy groups. The Expert Panel considered all public comments for incorporation into USP DC 2020.  The Healthcare Quality & Safety Expert Committee approved USP DC 2020 in December of 2019.

Guiding Principles

Similar to the 2019 version, the Expert Panel used the following guiding principles to inform their development of the USP DC 2020.

Types of Example Drugs Listed

The Expert Panel'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 Expert Panel has excluded most hospital-only, over-the-counter, and medications without FDA approval from the USP DC 2020. Some listed drugs may have over-the-counter products as well as prescription-only 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 assuring patient access to the drugs that patients need with the flexibility that health plans require in offering an affordable and effective benefit.

In creating the categories and classes, there are careful considerations to minimize the creation of categories or classes with less than three drug examples.

In creating the categories and classes, there was consideration in naming the category and class to be broad enough to encompass future mechanism of actions.

Approach to Placement of Example Drugs

The USP DC utilizes pharmacotherapeutic evidence within the context of FDA-approved indications for placing example drugs. 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 issue.

Combination products are placed in USP groupings distinguished by "Combinations" or "Other" under the respective USP Category.  If the combination product includes an API that improves absorption or efficacy of another API, the placement will be based on the API 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.