Drug Class Explained

Knowing the drug class of a substance can be an important piece of information. There are thousands of drugs belonging to a different drug class, and with many different uses and effects. Many drugs are misused or abused for different reasons.

The sheer number of drugs available, and the many drug class differences, can be overwhelming and confusing. Do you know the difference between barbiturates and benzodiazepines? This guide will help you to identify the drug class of the most abused substances, what their effects are, how they are abused, and how the federal government assigns their drug class.  Recovery from some addictive substances requires treatment at a rehab facility.

Alcohol Drug Class

The alcohol drug class is made up of numerous chemicals that include hydroxyl (-OH), a compound derived from hydrocarbons.1 The most common form of alcohol consumed in beverages is ethanol, which is included at varying strengths in:

  • Beer
  • Wine
  • Malt beverages (i.e., hard lemonade)
  • Distilled liquors (i.e., whiskey, brandy, etc.)

Usually, Alcoholic beverages that are produced through fermentation (beer, wine, and malt beverages contain no more than 14% alcohol. Beverages that are produced by distillation can contain any percentage up to 100%, or “absolute alcohol.”1

Other types of substances in the alcohol drug class include methanolisopropyl alcohol, and ethylene glycol. These types of alcohols are used for other purposes and should not be consumed. Drinking these types of alcohols can result in poisoning and possible death.

Alcohol is usually ingested by drinking. It is considered a depressant because it slows down most systems of the body. Symptoms that result from alcohol use include:2

  • Drowsiness
  • Impaired concentration and judgment
  • Slurred speech
  • Impaired coordination
  • Blurred vision
  • Nausea and vomiting
  • Mood changes and depression

Street Names for Alcohol

  • Booze
  • Sauce
  • Brew
  • Juice

Alcohol is addictive, and withdrawal symptoms will occur if alcohol is used regularly on a long-term basis. It isn’t on the United States Drug Enforcement Administration’s (DEA) schedule of controlled substances, but it is illegal for anyone in the United States under the age of 21 to purchase and consume alcoholic beverages.

Cannabinoids Class

The cannabinoid drug class refers to several natural chemicals derived from the cannabis sativa plant. This plant is well known by its common name, marijuana. Resin extracted from the cannabis plant is known by its common name, hashish.
The most common cannabinoids in its drug class that come from the marijuana plant are as follows:3

Tetrahydrocannabinol (THC) is the most common cannabinoid in marijuana and is the chemical that is responsible for the marijuana “high.”

Cannabidiol (CBD) is not psychoactive and is currently approved by the U.S. Food and Drug Administration (FDA) for the treatment of seizures.

Other cannabinoids in the drug class that are utilized for medicinal purposes include:

  • Tetrahydrocannibolic Acid (THCA)
  • Cannabidiolic Acid (CBDA)
  • Cannabinol (CBN)
  • Cannabigerol (CBG)
  • Cannabichromene (CBC)
  • Tetrahydrocannabivarin (THCV)
  • Cannabidivarin (CBDV)

These cannabinoids are used for a variety of physical and psychological ailments and are approved for use in some states, but not approved by the FDA.

Marijuana Leaves

A dried marijuana leaf mixture that contains cannabinoids can be smoked, mixed in food and eaten, or brewed as a tea to drink. The THC contained in marijuana is considered a depressant because it slows down the body’s systems. Some of the symptoms that result from the use of marijuana or THC include:

  • Euphoria followed by relaxation and drowsiness
  • Increased sociability and reduced inhibitions
  • Slower reaction time
  • Decreased/increased blood pressure
  • Increased appetite
  • Impaired balance and coordination
  • Hallucinations
  • Panic attacks/anxiety

Street Names for Marijuana

  • Pot
  • Grass
  • Herb
  • Reefer
  • Weed
  • Bud
  • Mary Jane
  • Hash

While most people who use marijuana or THC do not develop a true addiction to the drug, physical tolerance, and psychological dependence can develop with long-term use and use in higher doses. Marijuana and THC both continue to be classified as Schedule I substances by the U.S. DEA, meaning that they are illegal. Individual states have opted to change the drug class of both marijuana and THC and not to enforce the DEA’s classification.

Opioid Drug Class

The opioid drug class includes drugs that are extracted and produced from the opium poppy, as well as synthetic and partially synthetic versions of opium-based drugs which all act on the opioid centers of the brain. Drugs that are classified as opioids include:
  • Opium
  • Heroin
  • Morphine
  • Codeine
  • Fentanyl
  • Hydrocodone
  • Hydromorphone
  • Methadone
  • Oxycodone
  • Oxymorphone
  • Buprenorphine
  • Tapentadol
  • Tramadol
  • Meperidine

Most opioids are used medicinally for pain relief. The level and duration of pain relief provided depends on the drug and on how it is extracted or manufactured. Opioids are typically taken orally by pill or capsule, injected via a liquid solution, taken orally in a liquid solution, or administered via a suppository.

Most opioids are used medicinally for pain relief. The level and duration of pain relief provided depends on the drug and on how it is extracted or manufactured. Opioids are typically taken orally by pill or capsule, injected via a liquid solution, taken orally in a liquid solution, or administered via a suppository.
  • Euphoria
  • Drowsiness
  • Mental fog
  • Dizziness
  • Headache
  • Slowed breathing
  • Nausea/vomiting
  • Constipation or diarrhea

Street Names for Opioids

  • Smack (Heroin)
  • Morpho (Morphine)
  • Oxy (Oxycodone)
  • Blue (Oxycodone)
  • Dillies (Hydromorphone)
  • Captain Cody (Codeine)
  • Chine Girl (Fentanyl)

Opioids are highly addictive, causing physical and psychological dependence as well as tolerance. Also, due to the side effect of slowed breathing, an opioid overdose can be medically dangerous and possibly fatal. Because of this, all opioids appear on the DEA’s controlled substances schedule. Heroin is the only substance of the opioid drug class on Schedule I because heroin is the only opioid that is not used for medical reasons. Buprenorphine is on the Schedule III and Tramadol is on the Schedule IV. All other substances in the opioid drug class are on the Schedule II. Because of the widespread abuse of opioid medications in the United States, some individual states are tightening their laws regarding the classification and prescription use of opioids.4, 5

Stimulant Class

There are several substances that fall into the drug class of stimulants. They are called stimulants because they speed up the systems of the body, particularly neural activity. Stimulants may enhance the feeling of alertness and may temporarily give a person extra focus and energy. Stimulants include:
  • Cocaine
  • Methamphetamine
  • Amphetamine
  • Dextroamphetamine
  • Caffeine
  • Phenmetrazine
  • Methylphenidate6

Medications used to treat attention deficit hyperactivity disorder (ADHD) are considered stimulants. Adderall©, a popular ADHD medication, is a combination of amphetamine and dextroamphetamine. Stimulants are used to treat various conditions besides ADHD, including memory loss and other cognitive symptoms as well as weight loss. Stimulant use without a prescription is popular with people who must work long hours or stay up late to accomplish extended assignments, such as college students.

As stated previously, stimulants speed up the systems of the body. Some of the side effects of stimulants include:

  • Increased wakefulness and alertness
  • Increased breathing rate
  • Increased heart rate
  • High blood pressure
  • Decreased appetite
  • Irregular heartbeat

Street Names for Stimulants

  • Speed
  • Meth
  • Crank
  • Coke
  • Crystal
  • Snow
  • Crack

Stimulants are ingested in pill or capsule form, smoked, snorted through the nose, or injected. An overdose of stimulants can cause a heart attack or stroke and can be fatal. Cocaine and all forms of amphetamine, including methamphetamine, are classified as Schedule II controlled substances. Other stimulants may be classified as Schedule II or IV, depending on how strong the stimulant effect is. Caffeine is not regulated as a stimulant.

Benzodiazepine Drug Class

Benzodiazepines are synthetic medications that are used as sedatives for a variety of medical conditions. Some of these conditions include anxiety and panic disorders, seizures, muscle spasms, and insomnia. Benzodiazepines may also be used to treat alcohol withdrawal symptoms or to sedate patients before surgery. Here is a list of medications in the benzodiazepine drug class:
  • Midazolam
  • Oxazepam
  • Temazepam
  • Triazolam

Substances in the benzodiazepine drug class primarily act on the receptors of the brain to calm anxiety. They are all typically taken orally in pill or capsule form. Side effects of these medications can include:7

  • Drowsiness/sleepiness
  • Dizziness
  • Confusion
  • Memory loss/amnesia
  • Nausea
  • Blurry vision
  • Constipation
  • Sexual dysfunction
  • Slowed breathing
  • Impaired coordination

Street Names for Benzodiazepines

  • Benzos
  • Chill Pills
  • Candy
  • French Fries

Abruptly stopping benzodiazepine use can lead to severe withdrawal symptoms. The risk of overdose with benzodiazepines mainly occurs when people who use these drugs without a prescription combine them with alcohol or opioids. Even though benzodiazepines have been considered “safe” medications since they were introduced, the recent increase in benzodiazepine abuse and overdose, especially in combination with opioids, has led the DEA to classify substances in the benzodiazepine drug class as Schedule IV controlled substances.

Barbiturate Class

Barbiturates are synthetic medications that get their name from the compound they are made from, barbituric acid. The medications in the barbiturate drug class are tranquilizers that are quite potent and are used for a variety of medical conditions. Barbiturates are considered depressants because they slow down the central nervous system in the body, meaning the brain, spinal cord, and nerves. These drugs are classified as barbiturates:
  • Methohexital
  • Thiopental
  • Secobarbital sodium
  • Butobarbital
  • Pentobarbital
  • Amobarbital
  • Phenobarbital
  • Mephobarbital

In the past, barbiturates were commonly used to treat insomnia. Because of the strength of these medications and the risk of overdose, however, barbiturates are rarely prescribed for this purpose today. They are still used if other medications for insomnia are not effective. Substances in the barbiturate drug class are also used to sedate patients before surgery, to treat severe headaches, and to treat seizures.

The primary effect of barbiturates is drowsiness and sleepiness. Other side effects include:7

  • Relaxation
  • Euphoria
  • Headache
  • Nausea and vomiting
  • Confusion
  • Impaired coordination
  • Slurred speech
  • Poor judgment
  • Reduced consciousness or unconsciousness
  • Slowed breathing

In recent years, the use of barbiturates has decreased so much that they are now hard for recreational users to get. However, these drugs are still abused by some.

Street Names for Barbiturates

  • Barbs or Barbies
  • Downers
  • Sleepers
  • Goof Balls

Using barbiturates puts people at an increased risk of overdose. Even a very slight increase in the dosage of medications can cause an overdose. Normal barbiturate use can slow breathing. As mentioned above, an overdose can cause breathing to stop, resulting in death. Substances in the barbiturate drug class are now classified as Schedule II, III or IV controlled substances by the DEA, depending on the strength of each drug and on how it is used.

Drug Class for Prescription Sleep Aids

As the name states, sleep aids are medications that induce sleep. Prescription sleep aids are used to help people who have chronic insomnia. Sleep aids have historically been in the drug class of barbiturates or the drug class of benzodiazepines. Due to the side effects and dangers of overdose, the medical community now offers alternatives to these strong medications. Here are a few prescription sleep aids that aren’t in the barbiturate drug class or the benzodiazepine drug class, but that work on the same areas of the brain:8
  • Zaleplon (Sonata©)
  • Zolpidem (Ambien©)
  • Eszopiclone (Lunesta©)

Taken in pill or capsule form, these medications have fewer side effects than barbiturates or benzodiazepines, but they still have side effects, which include:

  • Significant morning grogginess
  • Headaches
  • Nausea
  • Difficulty breathing
  • Rebound insomnia
  • Depression
  • Drug tolerance

Because of these side effects, especially morning grogginess that can affect driving, medications in this drug class were placed on Schedule IV by the DEA.

Ramelteon (Rozerem©) is a new prescription sleep aid that acts similarly to the natural sleep hormone melatonin. Its risk of dependency is low, but it still has a couple of side effects, including dizziness (for any user) and worsening symptoms of depression (for those who are already depressed). Ramelteon is not classified as a controlled substance.

Hallucinogen Drug Class

The chemical agents in the hallucinogen drug class alter perception and cause hallucinations. The overall effect of hallucinogens is similar to psychosis, but the effect is not long-term and wears off after a few hours. Some hallucinogens are extracted from plants, and some are synthetic. Some substances in the hallucinogen drug class include:
  • Lysergic Acid Diethylamide (LSD)
  • Dimethyltryptamine (DMT)
  • Psilocybin
  • Mescaline/Peyote
  • Tenamfetamine (MDA)
  • 3,4-methylenedioxymethamphetamine (Ecstasy)
  • Phencyclidine (PCP)

Hallucinogens are not used for medical purposes. People use these drugs recreationally for their psychedelic effects. Some people use hallucinogens as a part of religious ceremonies to achieve a connection with the spiritual world. Street names for hallucinogens are:

  • Acid (LSD)
  • Dimitri (DMT)
  • Molly, Mandy (Ecstasy)
  • Buttons (Mescaline)
  • Magic Mushrooms (Psilocybin)

Most hallucinogens are taken orally by eating a plant part or taking a pill, or by smoking. Hallucinogens are not considered to be addictive, and most people who use them do so only occasionally. However, hallucinogens can still have adverse side effects. These include:1

A “bad trip” where the effects of the hallucinogen are unpleasant or frightening.

Flashbacks also called post-hallucinogen perception disorder

Delusional disorder, where a person becomes convinced that the frightening hallucinations from a bad trip are actually reality

Anxiety, depression, or mood disorders that last more than 24 hours after taking the drug

The use of hallucinogens may also put people at risk of entering dangerous situations, as the hallucinations they induce could cause people to go to unsafe areas or attempt unsafe actions. Substances in the hallucinogen drug class were placed on Schedule I by the DEA, meaning that they are illegal in the United States.

Steroid Drug Class

The steroid drug class includes hormones that affect body growth, sexual function, and other physiological functions in the body. Hormones are produced naturally by the body, but can also be synthesized. Anabolic steroids are the type most commonly taken to supplement those naturally occurring in the body. This type of steroid enhances the effects of testosterone, the male sex hormone. When additional anabolic steroids are taken, they cause an increase in muscle mass, as well as other masculine features. The names of some prescription anabolic steroids include:
  • Testosterone (Androderm©)
  • Androstenedione
  • Stanozolol (Winstrol©)
  • Nandrolone (Deca-Durbolin©)
  • Methandrostenolone (Dianabol©)

Physicians prescribe anabolic steroids for certain medical conditions. These include inadequate production of testosterone in the body due to congenital disabilities or illness, anemia, recovery from burns, HIV wasting syndrome, slowed growth in children, and certain types of breast cancer.9

Anabolic steroids are usually injected, but may also be taken in pill form or through a patch applied to the skin. People abuse anabolic steroids to attempt to enhance their body’s appearance and strength. Athletes may use anabolic steroids to attempt to enhance their physical performance during sports. This practice, called “doping,” has been banned by international sports organizations, including the International Olympic Committee.
Like other drugs, anabolic steroids have adverse side effects, including:

  • Fatigue
  • Loss of appetite
  • Mood swings
  • Restlessness
  • Reduced sex drive
  • Depression

Steroid use can become addictive and can result in steroid cravings and withdrawal symptoms if steroid use is stopped abruptly. Most substances on the steroids drug class are considered Schedule III drugs by the DEA.

Drug Class for Over-the-Counter Medications

Over-the-counter medications, often abbreviated OTC, are a drug class of medications that people can purchase without a prescription. Many OTC medications are safe, but a few can be addictive and may be abused for their side effects. Here is a list of medications in the OTC drug class that are commonly abused or misused:10
Dextromethorphan (Delsym©, Robitussin Cough©, Vicks 44©): is a cough suppressant found in cough syrup and cold medicine. People who abuse dextromethorphan may mix it with soda and drink it. This is called “robo-tripping” or “skittling.” They may also mix it with alcohol or marijuana to enhance the effects of these drugs. Side effects include confusion, excitement, nervousness, and irritability.
Loperamide (Imodium AD©): is used to relieve diarrhea. It is a synthetic opioid, so, when taken in very high doses, it produces a euphoric effect similar to other opioids. Side effects include abdominal pain, nausea, constipation, dry mouth, dizziness, and drowsiness. People can overdose on loperamide, and the overdose can be treated with naloxone, similar to other opioids.
Pseudoephedrine/phenylephrine (Sudafed©, Sudafed PE©): are found in decongestants and cold medicines and are used to relieve sinus congestion. Pseudoephedrine in large quantities can be used to make methamphetamine, or “crystal meth,” so the sale of OTC medications containing pseudoephedrine is now limited in the United States. Side effects include dizziness, headaches, insomnia, high blood pressure, and heart arrhythmias.
Diphenhydramine (Benadryl©, Nytol©, Sominex©): acts on the histamine centers of the brain, relieving allergy symptoms, and inducing sleep. It is abused for its ability to elevate mood, increase energy levels, and induce euphoric effects. Side effects include drowsiness, dizziness, fatigue, nausea, and urinary retention. An overdose of diphenhydramine can result in sinus tachycardia, agitation, or psychosis.
Acetaminophen (Tylenol©): is a pain reliever generally considered safe, but large doses of acetaminophen can cause liver damage or even liver failure. People who abuse acetaminophen often do so unknowingly, as so many OTC products contain acetaminophen that a person may not be aware that they are taking multiple doses. Liver damage can also occur when a person combines acetaminophen with alcohol. Side effects include drowsiness as well as liver and kidney toxicity.
Oxybutynin (Oxytrol©, Ditropan XL©): is used for symptoms of overactive bladder. While it is available over the counter, it should be used under the supervision of a physician. People abuse oxybutynin for its euphoric effects, inducing relaxation, and reduction of symptoms of depression. Side effects include sleepiness, dizziness, blurred vision, constipation, dry mouth, and confusion.
Antacids (Tums©, Mylanta©, other brands) are used to relieve the symptoms of heartburn, upset stomach, and acid indigestion. While people do not abuse antacids to get “high,” they may take them to relieve the side effects of other medications. People who take antacids too often or over long periods may end up with an “acid rebound” effect, causing worse symptoms. Long-term use of these medications can also lead to aluminum toxicity or alkalosis in some people.
  1. Babor, Thomas, et al. (1994) “Lexicon of alcohol and drug terms,” PDF. World Health Organization; Geneva, Switzerland.
  2. Facing Addiction in America: the Surgeon General’s Report on Alcohol, Drugs and Health. U.S. Department of Health & Human Services, 2016.
  3. https://www.dea.gov/factsheets
  4. https://medlineplus.gov/druginformation.html
  5. https://www.medicalnewstoday.com/articles/310066.php
  6. https://www.drugs.com/drug-class/benzodiazepines.html
  7. https://www.helpguide.org/articles/sleep/sleeping-pills-and-natural-sleep-aids.htm
  8. https://www.medicinenet.com/anabolic_steroid_abuse/article.htm
  9. https://www.mdlinx.com/internal-medicine/article/3783
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