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 Safety & Quality 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

  • December 17, 2021: USP DC 2022 published
  • October 4 - October 29, 2021: USP DC 2022 Draft was posted for Public Comment
  • December 18, 2020: USP DC 2021 was published

If there are additional questions, please contact

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
  • Reviewing formularies and comparing formulary design and benefits

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, 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 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 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)
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 Every 3 years* Annual
Current Publication Version USP MMG v8.0 USP DC 2022
Intended Publication Date

February 1, 2023

December 17, 2021

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

Organization of USP DC 2022

The USP DC 2022 contains a listing of single entity drug products, combination drug products, and vaccines.

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 2022 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 2022 there are 172 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 2022 there are 122 pharmacotherapeutic groups.

Example Drug 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. In USP DC 2022, there are 1846 example drug placements.
Filter by Type

Users can filter only this column to choose 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
(Class)- USP Class
(PG)- USP Pharmacotherapeutic Group
(yes)- The drug contains more than 1 active ingredient
(no)- The drug contains only 1 active ingredient



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

The USP Drug Classification was created by an Expert Panel during the 2015-2020 cycle formed under the Healthcare Quality & Safety Expert Committee. For the 2020-2025 cycle, a new USP Drug Classification Subcommittee was formed to continue the work. The Subcommittee consists of academicians, practitioners, formulary experts, patient advocates, and clinicians. This Subcommittee advises the Healthcare Safety & 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 2022 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.

Public Comment Process

The USP DC 2022 Proposed Draft was available on the website for public comment from October 4th until October 29th, 2021. Stakeholders had the opportunity to provide comments via email, public comment form, and stakeholder 1:1 meetings.

Several requests were evaluated for incorporation in the proposed draft. Commenters included drug manufacturers, regulators, health plans/PBMs, academia, and patient advocacy groups. The Subcommittee considered all public comments for incorporation into USP DC 2022. The Healthcare Safety & Quality Expert Committee approved USP DC 2022 in December of 2021.

Guiding Principles

As with the 2021 version, the USP Drug Classification Subcommittee used the following guiding principles to inform their development of the USP DC 2022.

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 2021 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 assuring 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

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 2022

(published December 17, 2021)

•    Download USP Drug Classification 2022

USP Drug Classification 2021

(published December 18, 2020)

•    Download USP Drug Classification 2021