What Are the Different Classes of Drugs?

Drug classification gives a language that people can use to discuss both pharmaceuticals and illicit drugs. It is essential to know what gets said about a substance and why. There are different ways of categorizing drugs, but these categories exist to convey information about a substance.

This system of Classifications of drugs is probably the best-known. The use of schedules to describe the characteristics of drugs prevents misunderstandings from one person to the next. Schedules tell how potentially dangerous a drug can be. The factors considered are medical use, the potential for abuse, and safety (how likely dependency is to occur).

Scheduling under the Controlled Substances Act

In 1970, the FDA (Food and Drug Administration) created the Comprehensive Drug Abuse Prevention and Control Act to help protect the general public from potentially dangerous and addictive drugs. Part of this Act introduced five schedules or classes that drugs fit into to keep the public informed.

Drugs schedule

This schedule is from one, the most potential harm, to five, the slightest chance of injury when taking a prescribed or illicit substance.

Schedule I

These substances or chemicals are classified as drugs with no current medical applications. These are also highly addictive substances with a high potential for abuse and a high risk of either psychological or physical dependence. Also, This class includes well-known street drugs like heroin, cannabis, cocaine, and LSD.

Schedule II

These substances also have a high potential to cause the user to become dependent. These drugs considered dangerous but include both illicit and prescription drugs. 

Drugs like methamphetamine appear in this category, along with prescription opioids. These fall into this schedule due to the risks associated with the use of painkillers being similar to illicit drug use, and why you will find many of these types of substances in schedule II.

Schedule III

This classification applies to substances that have moderate potential for developing dependency. The abuse rates are significantly lower than the first two schedules, but they still have associated risks. These will have less than 90mg of narcotic per unit, like Tylenol with codeine, and also include substances such as steroids and ketamine.

Schedule IV

These are substances that are mostly safe for most users. There are low rates of abuse as well as a low risk of dependency. This class includes drugs like Xanax, Soma, Darvocet, and Ativan. This schedule of drugs is considered safe for most people.

Schedule V

These drugs have few incidences of abuse or physical dependence. They are usually limited to preparations for another substance with small amounts of narcotics. Also, These medications meant for pertussis or have analgesic purposes. Drugs under the names Lyrica, Robitussin AC, and Motofen form part of this schedule.

What is a drug class?

A drug class is a group of substances that get grouped for several reasons. However, These classifications can refer to chemical similarities, the effects on the user, or a legal definition. These different ways of grouping substances serve to identify and understand the drug being looked at with ease.

Drugs routinely get separated in a few ways in the United States. They can grouped according to the chemical compounds making up the substance or by the pharmacological effect that drugs will have on a person. Finally, the Schedule of Controlled Substances gives a way to categorize medicines in a legally recognized way.

Chemically similar drug classes

Grouping drugs together using chemical similarity is another way of classifying drugs. Chemically similar drugs will have similar impacts and risks for the user.

Classifications of chemically similar drugs

This way of classifying drugs is also helpful for treatment. Chemically similar substances will have similar rates of addiction. A person using one substance in a group is more likely to use or abuse other substances that might have chemical similarities.


Alcohol is one of the most widely available and easy-to-obtain substances. Also, It is legal in every state and on the federal level. Alcohol is a central nervous system depressant and can induce feelings of euphoria and diminishes inhibition. It can also result in damage to your liver. 


Opioids get prescribed by medical professionals to treat acute pain in patients; for example, after surgery or to relieve pain from severe injuries. However, this type of medicine can cause quick and sudden dependency, resulting in a psychological and physical dependence compounded by excruciating withdrawal when trying to stop using.

Other chemically defined classes

The other groups classified as chemically similar include hallucinogens, cannabinoids, and tranquilizers. Each group gets categorized so they are easily identifiable for treatment and prevention purposes.

Drugs with similar effects

Substances get grouped into classes according to the effect that results from their consumption. Also, These legal and illegal drugs, solely grouped by how they make a person feel.

Classifications of drugs with similar effects

There are four agreed-upon classes of similar effects.

  • Depressants
  • Stimulants
  • Inhalants
  • Hallucinogens

Some believe cannabinoids are a fifth item on the list due to how their effects differ from the other already established groups.

Depressants and stimulants act by causing reactions or blocking reactions from the central nervous system. However, Depressants include heroin, opioids, barbituates, and GHB. Stimulants are drugs like methamphetamine, cocaine, ADD meds, or Adderall.

Inhalants rely on your lungs to disperse the drugs through the body, sometimes called huffing, to achieve the desired results. Also, These medicines typically get administered through nebulizers and inhalers.

Hallucinogens (also called psychedelics) like mushrooms or ecstasy (MDMA) will alter the individual’s perception of reality on a grand scale. This group includes LSD, which can improve a person’s mood, thoughts, or perception when carefully monitored.

Final Thoughts

Drug Classifications have come about to understand the effects and what to expect from a substance. These classifications also serve as a warning for the general population about the potential harm caused by substance abuse. Not only for quantification and understanding, but classifications also help to fight against addiction and intend to help those who need it most.

Leave a Reply

%d bloggers like this: