Understanding Medications: Who Decides the Classification?

October 15, 2025 •

5 min read

In the United States, drugs, substances, and precursor chemicals are classified into five distinct categories or schedules based on their medical use and potential for abuse, as determined by federal agencies. Understanding who decides the classification is crucial, as the answer involves multiple regulatory and scientific bodies, each with a different focus and purpose.

Quick Summary

Drug classification is determined by multiple entities, including the DEA for controlled substance schedules based on abuse potential and the FDA for approvals based on safety and efficacy. Other systems like ATC and USP categorize drugs therapeutically for research and health policy.

Key Points

Multiple Authorities: The classification of medications is not decided by one single body, but by multiple regulatory agencies and scientific organizations, including the FDA and DEA in the U.S..
FDA's Focus: The FDA determines whether a medication is safe and effective for its intended use, which dictates its approval and whether it will be sold by prescription or over-the-counter.
DEA's Focus: The DEA classifies drugs with abuse potential into five controlled substance schedules, which determines their legal control and handling requirements.
Therapeutic Classification: International systems like the WHO's ATC and non-profit organizations like the USP classify drugs based on their therapeutic effects, mechanism of action, and chemical properties for research and health policy.
Dynamic Process: Drug classification is not static; it can change over time based on new scientific evidence regarding a drug's abuse potential or medical use.
Comprehensive Framework: The combination of regulatory and therapeutic classifications creates a comprehensive system that governs drug development, marketing, control, and clinical use globally.

The classification of medications is not determined by a single entity but rather by a complex web of regulatory bodies, scientific organizations, and legislative acts. This multi-layered system ensures public safety by controlling the distribution of drugs with abuse potential, standardizing therapeutic information for healthcare providers, and regulating market access. In the United States, key players include the Food and Drug Administration (FDA) and the Drug Enforcement Administration (DEA), whose roles are distinct yet interconnected.

Regulatory Classifications: The FDA and DEA

Two federal agencies form the backbone of regulatory drug classification in the U.S., each focusing on different aspects of a drug's lifecycle.

The FDA's Role in Approval and Prescription Status

Before a drug can be legally marketed in the United States, it must undergo a rigorous approval process by the FDA. The FDA evaluates a drug's safety, efficacy, and intended use through clinical trials and scientific data. This assessment fundamentally determines whether a medication will be available by prescription or over-the-counter (OTC).

New Drug Application (NDA): A manufacturer submits an extensive NDA to the FDA, detailing all study results and manufacturing specifics. FDA review teams, including pharmacologists and statisticians, evaluate the data to ensure the drug meets safety and effectiveness standards.
Post-Market Monitoring: The FDA's oversight continues after approval. Through its Adverse Event Reporting System, the agency collects and analyzes reports of medication problems in the general population, which can lead to label changes or product recalls if safety concerns arise.
Product Classification: The FDA's determination of whether a product is a drug, device, or biologic is based on statutory definitions and available scientific evidence. A product's primary intended purpose and mechanism of action heavily influence this initial classification.

The DEA's Controlled Substances Schedules

Created by the Controlled Substances Act (CSA) of 1970, the DEA focuses specifically on drugs with potential for abuse or dependence. The DEA places these substances into one of five schedules, from Schedule I (highest risk) to Schedule V (lowest risk). The scheduling decision is made by the DEA, often taking into account analyses and recommendations from the Department of Health and Human Services (HHS) and FDA after a new drug is approved.

Factors for scheduling include:

The drug's potential for abuse.
Scientific evidence of its pharmacological effect.
The risk to public health.
The drug's history and pattern of abuse.
The substance's potential for psychological or physical dependence.

Therapeutic and Clinical Classifications

Beyond the regulatory aspects of safety, efficacy, and abuse potential, other systems classify drugs based on their function. These classifications are used by healthcare providers, researchers, and public health agencies to organize and understand medications based on their effects on the body.

Anatomical Therapeutic Chemical (ATC) Classification System

Managed by the World Health Organization (WHO), the ATC system is a global standard for classifying therapeutic drugs. It provides a hierarchical structure, classifying drugs at five levels according to the organ system they affect, their therapeutic purpose, and their pharmacological and chemical properties. This system is vital for comparative drug utilization statistics and health policy.

ATC Classification Levels:

1st Level: Anatomical main group (e.g., Nervous system).
2nd Level: Therapeutic main group (e.g., Analgesics).
3rd Level: Pharmacological subgroup (e.g., Opioids).
4th Level: Chemical subgroup (e.g., Opium alkaloids).
5th Level: Chemical substance (e.g., Morphine).

United States Pharmacopeia (USP) Classification

The USP is a non-profit, non-governmental organization that establishes quality standards for prescription and OTC drugs in the U.S.. The USP Drug Classification (USP DC) system is an independent, hierarchical system used to support formulary management in various healthcare settings. It categorizes drugs by therapeutic use, mechanism of action, and formulary classification.

Comparing Key Classification Systems

To clarify the distinctions, here is a comparison of the DEA's scheduling and the FDA's regulatory approach.


Feature	DEA Controlled Substance Scheduling	FDA Approval & Classification
Primary Purpose	Regulate drugs with abuse potential; legal control.	Ensure safety and efficacy for marketing; inform use.
Primary Factor	Potential for abuse and dependence.	Safety and effectiveness for intended use.
Authority	DEA makes final scheduling decisions, often with input from FDA/HHS.	FDA has sole authority to approve a drug for marketing.
Classification Scale	Schedules I-V (1 is highest abuse risk, 5 is lowest).	Prescription (requires authorization) vs. Over-the-Counter (OTC).
Examples	Heroin (Schedule I), Adderall (Schedule II), Ketamine (Schedule III).	Acetaminophen (OTC), Lisinopril (Prescription).

The Lifecycle of a Drug's Classification

From its inception to its market availability, a drug can undergo several classification assessments.

Initial Research: A promising compound is studied in preclinical research to understand its effects, which informs initial classification ideas.
FDA Review: The FDA evaluates the drug's safety, efficacy, and intended use, determining its prescription or OTC status. This process includes a benefit-risk analysis.
DEA Evaluation: If the drug has abuse potential, the DEA receives an analysis and recommendation from HHS and the FDA to determine its controlled substance schedule.
Clinical Use: Healthcare providers use therapeutic classifications, such as ATC or USP, to manage formularies and make treatment decisions.
Post-Market Surveillance: As a drug is used more widely, ongoing monitoring can lead to reclassification. The DEA may move a substance from one schedule to another if new evidence on its abuse potential or medical use emerges.

Conclusion

In summary, there is no single entity that decides medication classification. The process is a collaborative effort involving federal regulatory bodies like the FDA and DEA, as well as international organizations like the WHO and non-governmental entities such as the USP. While the FDA focuses on market approval based on safety and efficacy, the DEA specifically regulates controlled substances based on abuse potential. Concurrently, other systems provide therapeutic classifications for clinical practice and public health analysis. Together, these different classification schemes provide a comprehensive framework that governs the use, control, and understanding of medications, protecting public health while ensuring access to necessary therapies.

Why Understanding Classifications is Important

For patients and healthcare providers, understanding these different classification systems is critical for several reasons.

Informed Prescribing: Providers rely on both regulatory and therapeutic classifications to select appropriate and safe treatments, considering potential drug interactions and side effects.
Patient Safety: Awareness of a drug's classification, especially controlled substances, helps prevent misuse, addiction, and diversion.
Public Health: Organizations and researchers use these standardized classifications to monitor drug usage trends and assess public health impacts globally.
Legal Compliance: For pharmacies and healthcare facilities, adhering to the legal requirements dictated by agencies like the DEA is mandatory for handling and dispensing controlled substances.
Drug Development: For pharmaceutical companies, navigating the various classification requirements is an essential part of the drug development and marketing process.

Find more information on drug scheduling from the DEA's Diversion Control Division website.

Frequently Asked Questions

The FDA primarily focuses on whether a drug is safe and effective for its intended medical use, leading to approval for marketing as either a prescription or over-the-counter (OTC) medication. The DEA, under the Controlled Substances Act, classifies drugs with abuse potential into five schedules to determine their legal control and handling requirements.

The DEA assigns a drug to one of five schedules based on its potential for abuse, acceptable medical use, and potential for psychological or physical dependence. The DEA consults with the Department of Health and Human Services and the FDA before making a final scheduling decision.

The Anatomical Therapeutic Chemical (ATC) classification system is a tool maintained by the World Health Organization (WHO) that classifies drugs based on the organ or system they act upon, their therapeutic and pharmacological properties, and their chemical characteristics. It is used worldwide for drug utilization studies.

Yes, a drug's classification can be changed based on new scientific evidence. For example, the DEA may move a controlled substance from one schedule to another if new data indicates a change in its abuse potential or medical use.

The FDA determines whether a medication is a prescription or over-the-counter (OTC) drug during the approval process. Prescription drugs generally require supervision from a healthcare professional, while OTC medications are considered safe for self-administration when used as directed.

A therapeutic classification groups drugs based on their therapeutic use or the condition they are intended to treat. For example, antihypertensives are a therapeutic class of drugs used to treat high blood pressure, while antibiotics are used for bacterial infections.

Drug classification is important for patient safety, informed prescribing, legal control, and public health monitoring. It helps healthcare providers select appropriate treatments, prevents misuse and addiction, and allows agencies to regulate drugs based on their risks and benefits.