• What Are The Schedules Of Drugs?

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    What Does A Drug Schedule Mean?

    If you’ve ever caught yourself wondering about the different schedules of drugs or how drug classification works, you’re not alone. Drugs – both pharmaceutical and illegal – are classified in several ways, so it can be tricky figuring out the differences between types of drugs, drug schedules, and other categories.

    Drug schedules in the United States were first defined by the Controlled Substances Act, which sought to identify and organize drugs under federal law into categories based on their potential for harm.


    Drug schedules categorize drugs into five classifications based on three main factors:

    1. Addictive Properties
    2. Potential for Abuse
    3. Medical Usage

    The CSA drug schedules consist of controlled substances that are either illegal or prescription drugs.

    In general, drugs are ranked from Type I (most addictive and potentially harmful) to Type V (very low likelihood of addiction and harm.) To schedule a new drug, the DEA first determines whether it can be abused. If the answer is “yes, the drug can be abused,” then the DEA moves the drug forward in the scheduling system, where its potential for abuse and harm dictates its classification.1

    What is the Controlled Substances Act?

    The United States established the Controlled Substances Act (CSA) in 1970, and President Nixon signed it into law on October 27th of that year. The CSA was established to regulate how drugs could be produced, sold, and used in the United States.2

    The main goal of the Controlled Substances Act was to protect the public from harm induced by addictive and damaging substances as well as to create a system of rules and regulations that assessed the varying degree of danger of each drug schedule.

    The schedule of drugs can be adjusted by the U.S. Drug Enforcement Agency (DEA), the U.S. Food and Drug Administration (FDA), the Department of Health and Human Services, or any other party that petitions the DEA. The Controlled Substances Act applies to federal law, meaning there may be variations in the enforcement of drug schedules from state to state.

    The Drug Schedules

    Pharmacist working at a pharmacy organizing products while wearing a protective face mask during the coronavirus outbreak.


    Schedule I substances are recognized as incredibly dangerous drugs. These substances typically present the highest potential for physical or psychological dependency and abuse. Schedule I drugs currently have no medical purposes. They are not considered safe even with medical supervision, and they are illegal under federal law.

    Common Schedule I drugs include:3

    • Heroin
    • LSD (lysergic acid diethylamide)
    • Ecstasy
    • Marijuana
    • Peyote
    • Quaaludes (i.e. methaqualone)
    • GHB (gamma-hydroxybutyric acid)

    It’s important to note that federally, the DEA still considers marijuana a Schedule I drug. Regulations vary from state to state, though, and many researchers have expressed frustration at marijuana’s Schedule I classification. The classification of marijuana prevents further research on its potential health benefits and consequences.


    Schedule II substances are at high risk for psychological or physical dependency and abuse. Unlike Schedule I drugs, Schedule II drugs have accepted uses in medical settings in the U.S. However, their use is highly controlled and supervised.

    Common Schedule II drugs include:4

    • Cocaine
    • Methamphetamine
    • PCP (phencyclidine)
    • Fentanyl
    • Ritalin
    • Adderall
    • Methadone
    • Morphine
    • Hydromorphone (Dilaudid)
    • Meperidine (Demerol)
    • Oxycodone (OxyContin, Percocet)


    Schedule III drugs are considered much less dangerous than Schedule I or II drugs. Substances in this category are accepted for medical use and may be prescribed for common illnesses, injuries, or other health matters.

    While the danger for abuse and addiction still exists, these types of drugs do not present the same levels of danger as Schedule I or II and can often be purchased at your local pharmacy with a prescription.

    Common Schedule III drugs include:5

    • Ketamine
    • Vicodin
    • Anabolic steroids
    • Codeine
    • Barbiturates
    • Products with > 90 mg of codeine (i.e. Tylenol with codeine)


    Schedule IV substances have a lower risk for dependence and abuse than Schedule III drugs. These drugs serve clear medical purposes and are commonly prescribed by physicians for a range of medical uses.

    Common Schedule IV drugs include:6

    • Xanax (Alprazolam)
    • Ativan (lorazepam)
    • Valium (diazepam)
    • Klonopin (clonazepam)
    • Soma (carisoprodol)
    • Darvon (propoxyphene)
    • Ambien (zolpidem)
    • Tramadol


    Schedule V substances are the least likely to incur physical or mental dependence or to lead to harm. Physicians prescribe these substances for a wide variety of health matters, including analgesic, antidiarrheal, and antitussive purposes. Conditions like fibromyalgia and irritable bowel syndrome often require prescriptions for Schedule V substances.

    These drugs are Schedule V because they often contain limited quantities of narcotics that in high amounts could lead to abuse and dependency.

    Common Schedule V drugs include:7

    • Cough medicines with < 200 mg of codeine per 100 ml
      • Robitussin AC
      • Phenergan with codeine
    • Ezogabine

    Other Drug Categories

    Drug classifications are determined in a few ways. The CSA classifies drugs based on their potential for harm and dependency, as well as their medical usage.

    However, drug categories are also assigned by the type of drug, their chemical make-up, their effects on the brain and body, and different agencies creating their own system drug classification system. Drugs are easily categorized into five classes of drugs, assigned by their main features and chemical properties. These five classes of drugs are:

    • Narcotics
    • Hallucinogens
    • Anabolic Steroids
    • Depressants
    • Stimulants

    These classes are not to be confused with the USP Drug Classification system or the Anatomical Therapeutic Classification System.


    You might be surprised to find that several common, drug-store pharmaceuticals are not on the schedule of drugs. Drugs whose risks are considered minimal and are not likely to cause harm and endanger the public aren’t classified as “controlled substances” or included in the schedule of drugs.

    Drugs like diabetes medication, heart pressure medication, asthma inhalers, antibiotics, and most over-the-counter prescriptions are not considered potentially addictive or harmful, so you won’t find them included in the CSA’s schedule of drugs. Alcohol and Tobacco are also currently not regulated under the CSA.


    1. https://www.dea.gov/drug-information/drug-scheduling
    2. https://www.dea.gov/drug-information/csa
    3. https://www.deadiversion.usdoj.gov/21cfr/cfr/1308/1308_11.htm
    4. https://www.deadiversion.usdoj.gov/21cfr/cfr/1308/1308_12.htm
    5. https://www.deadiversion.usdoj.gov/21cfr/cfr/1308/1308_13.htm
    6. https://www.deadiversion.usdoj.gov/21cfr/cfr/1308/1308_14.htm
    7. https://www.deadiversion.usdoj.gov/21cfr/cfr/1308/1308_15.htm