Drug Class Explained

Are All Drugs Created Equal?

Are All Drugs Created Equal?

Drug Class Explained

Are all Drugs Created Equal?

What is a Drug Class?

Thousands of different types of drugs exist, ranging from illegal substances to legally and medically prescribed drugs. Each drug has a different effect, function, and purpose. To organize them, each drug is placed in a drug class:

Chemical structure


Drug scheduling

In the United States, the Controlled Substances Act placed all substances that are federally regulated into one of five different schedules. Substances are placed into schedules according to the drug’s medical use, potential for abuse, and safety.

The primary categories of drug class are:

  • Stimulants
  • Depressants
  • Hallucinogens
  • Opioids
  • Inhalants
  • Over-the-counter drugs
  • Steroids
  • Cannabinoids

Drug Class: Stimulants

Stimulants increase the activity of the central nervous system. Drugs in the stimulant drug class increase alertness, attention, energy, blood pressure, heart rate, and breathing rate. In large doses, stimulants may cause heart failure and seizures.

What Commonly Known Drugs are Stimulants?

Prescription drugs used as medications for ADHD and narcolepsy are examples of medicines in the stimulant drug class. These include amphetamine (Adderall, Benzedrine) and methylphenidate (Concerta, Ritalin). Illegal and recreational substances such as cocaine, methamphetamine, MDMA (ecstasy) and cathinone are also stimulants. The most popular and widely used stimulant in the world however, is… caffeine! Yes, coffee is a drug. While caffeine is relatively safe, in large doses, it can have negative effects.

Side-Effects of Using Stimulants

Possible side effects of illegal stimulants (cocaine, ecstasy, etc.) include:

Abdominal pain

Chills / sweating

Dental problems

Erratic / violent behavior

Heart attack

Increased heart-rate / blood pressure

Liver, kidney, heart failure

Nasal damage

Panic attacks

Stroke, seizure, coma





Increased body temp


Memory loss



Weight loss

Blurred vision


Enlarged pupils


Increased energy / alertness


Narrowed blood vessels



Possible side effects of prescription medication in the stimulant drug class (Adderall, Ritalin, etc.) include:




Increased blood sugar

Insomnia / wakefulness

Sleep problems



Increased blood pressure

Increased body temp


How Common is Stimulant Misuse?

According to the 2018 National Survey on Drug Use and Health, approximately 5.1 million people over the age of 12 misused prescription stimulants.1 This corresponds to 1.9% of the population.1 The average age that stimulants are first used is 22.3 years old.2

Drug Class: Depressants​

Depressants are drugs that impair the functioning of the central nervous system. Alcohol and tobacco are recreational examples of depressants, while benzodiazepines and barbiturates are the most commonly used prescription medications in the depressant drug class. Because depressants sedate the brain, they are often prescribed for sleep disorders, anxiety, and stress.

Side-Effects of Depressants

Depressants can cause side-effects such as slurred speech, dizziness, and loss of coordination. In high doses, depressants have the potential to be abused and can lead to overdose.


Did you know that alcohol is also considered to be a drug and is placed in the depressant drug class? Drugs are typically thought of in their pill or powder form, and it is not well-known that alcohol is also a drug (as is coffee!). The fermentation of grains and fruits creates alcohol. Fermentation is a chemical process where yeast acts on certain ingredients in food, creating alcohol.

What are the Effects of Alcohol?

Alcohol is in the depressant drug class because it slows down vital functions, leading to slurred speech, a lack of balance and coordinated movements, a lack of perception, and a slowing of reflexes and reaction times. Alcohol affects the mind in the sense that it can distort judgment, ability to make decisions, and rationality. This is why people often make bad decisions while under the influence of alcohol, such as drinking and driving.

While consumption of one or two drinks may cause a body to feel stimulated, happy, and relaxed, as alcohol intake increases, so do alcohol’s depressant effects. This may cause a loss of coordination and control. An excess of alcohol consumption can lead to alcohol overdose, which can cause unconsciousness, coma, and even death.

What are the Different Types of Alcohol?

It is important to know that alcohol comes in various forms and strengths. The higher the alcohol percentage, the more severe of an impact it will have on the body.

Popular alcoholic beverages and their strengths:

Beer 2-6% alcohol

Cider 4-8% alcohol

Wine 8-20% alcohol

Tequila 40% alcohol

Rum 40+% alcohol

Brandy 40+% alcohol

Gin 40-47% alcohol

Whiskey 40-50% alcohol

Vodka 40-50% alcohol

Liqueurs 15-60% alcohol

While it may be possible to consume a couple of beers before feeling the effects of the alcohol, it will require much less vodka or tequila to achieve the same effects. It is important to be aware of the strength of alcohol to know when to stop drinking.

How Common is Alcohol Use?

In 2018, approximately 139.8 million Americans over the age of 12 reported using alcohol.1 Of these 139.8 million people, nearly half (48%) reported being binge drinkers, and 1 in 8 people were heavy drinkers.1 The average age that alcohol is first used is 17.6 years old.2


Benzodiazepines are a type of sedative that are mainly prescribed for anxiety, panic disorders, and insomnia. They might also be prescribed for severe muscle spasms, tremors and seizures. Benzodiazepines cause feelings of calmness and sedation by increasing the level of GABA (a neurotransmitter) in the brain. Medications in this drug class might also help a patient to calm down before surgery or relax a person that is afraid of flying. Taking benzodiazepines can cause drowsiness and grogginess, and it may lead to rebound insomnia the following night.

Some common brand name benzodiazepines are Xanax, Librium, Klonopin, Valium, Dalmane, Ativan, Serax, Restoril and Halcion.

How Common is Benzodiazepine Misuse?

According to the 2018 National Survey on Drug Use and Health, approximately 5.4 million people over the age of 12 misused prescription benzodiazepines. This corresponds to about 2% of the population.1


Barbiturates are a type of depressant that were used mainly in the 1960s and 1970s for anxiety, insomnia, epilepsy, and as an anesthetic. Barbiturates are placed in the depressant drug class because they impact the central nervous system by inhibiting the activity of nerve cells in the brain. Today, barbiturates are used only for severe insomnia, seizures that haven’t responded to other medications, to induce anesthesia, and in combination with acetaminophen and caffeine for the treatment of headaches.

Side Effects of Taking Barbiturates

Barbiturates can cause a ‘high’ feeling and can induce drowsiness, disinhibition, and intoxication. Other side effects include confusion, diarrhea, dizziness, headaches, irritability, low blood pressure, nausea, vomiting, and vertigo. In large doses, barbiturates may cause confusion, slurred speech, loss of coordination, speech disturbances and shallow breathing. An excessively high dosage can lead to a loss of consciousness, breathing problems, overdose and even death. Barbiturates are highly addictive which is why they are rarely prescribed today and have largely been replaced by benzodiazepines.

Drug Class: Hallucinogens​

Hallucinogens are a category of mind-altering drugs that cause false perceptions of reality. As the name would imply, hallucinogens might induce hallucinations (seeing things that aren’t actually there). Hallucinogens affect the brain’s level of serotonin, which impacts cognition and memory.

A sub-category of hallucinogens is dissociative drugs, such as ketamine, which cause a feeling of detachment from reality. Dissociative drugs may also cause hallucinations

Which Commonly Known Drugs are Hallucinogens?

Examples of non-dissociative hallucinogens include Mescaline, DMT, LSD, and Psilocybin. Dissociative drugs include ketamine and PCP.

Side-Effects of Using Hallucinogens

Taking non-dissociative hallucinogens, such as LSD, might have the following side-effects:

Distorted perception of reality


Increased heart-rate / blood pressure




Impulsive behavior


Rapid mood swings

Increased body temp

Visual disturbances

Dry mouth

Increased body temp

Loss of appetite


Taking dissociative hallucinogens, such as Ketamine, might have the following side-effects:

Attention, learning, and memory problems

Difficulty breathing


Loss of movement / coordination

Muscle stiffness



Dreamlike state

Increased blood pressure

Memory loss



How Common is Hallucinogen Use?

According to the 2018 National Survey on Drug Use and Health, approximately 5.6 million people (2% of the population) over the age of 12 used hallucinogens.1 The average age that hallucinogens are first used is 19.6 years old.2

Drug Class: Opioids ​

Opioids are pain medications that block sensations of pain to the brain. Opioids were originally made from the natural opium poppy plant, but they can now be made synthetically. Substances in the opioid drug class are typically prescribed for moderate to severe pain and can cause intense sedation and feelings of euphoria. For that reason, opioids are often abused and have a high risk of addiction.

What Commonly Known Substances are in the Opioid Drug Class?

A commonly known non-prescription opioid is heroin. Heroin is highly addictive and has a high risk of abuse.

Prescription opioids include codeine, fentanyl, hydrocodone, hydromorphone, meperidine, methadone, morphine, oxycodone, and oxymorphone.

Side-Effects of Using Opioids

Taking prescription opioids could result in the following side effects:



Feelings of euphoria

Lowered blood pressure

Pain relief



Heart and respiratory problems

Muscle weakness



Lowered heart rate


Abusing prescription opioids or taking illegal opioids such as heroin could result in the following side effects:

Clouded thinking



Impaired coordination

Liver or kidney disease

Slowed breathing and heart rate

Warm, flushed skin

Collapsed veins

Dry mouth

Heavy feeling in hands / feet




How Common is Opioid Use?

In 2018, about 10.3 million people over the age of 12 misused opioids. This is approximately 3.7% of the U.S. population.1The majority of these people (9.9 million) misused prescription pain relievers, while the remaining 808,000 used heroin.1 The average age that opioids are first used is 25.8 years old.2

Drug Class: Cannabinoids​

Cannabinoids are naturally occurring compounds that are found in the Cannabis plant that impact cannabinoid receptors in the body. Cannabinoid receptors are often found in the brain and the immune system. Compounds in the cannabinoid drug class bind to cannabinoid receptors in the body, with each connection having different effects.

Two commonly known cannabinoids are found naturally in the marijuana plant. They are Tetrahydrocannabinol (THC) and Cannabidiol (CBD). THC is the component of marijuana that causes the feeling of high when marijuana is smoked or vaporized. THC has psychoactive effects as well as pain-relieving effects. CBD is another component of marijuana that does not cause a feeling of high but has many medical benefits. CBD is increasingly used to help people to sleep, to feel calm, and to treat anxiety.

There are also synthetic cannabinoids, which are human-made cannabinoid chemicals that are similar to the THC found in marijuana but can be stronger and more dangerous.

Side-Effects of Cannabinoids

Possible side effects include:



Heart attack





Increased heart rate





Increased blood pressure


How Common is Cannabis Use?

Cannabis is one of the most widely used drugs in America. In 2018, 43.5 million people reported using marijuana, which is about 15.9% of the population.1 This number is higher than any other year prior. The average age that cannabis is first used is 19 years old.2

Drug Class: Inhalants​

Inhalants are a category of drugs that are inhaled to produce mind-altering or psychoactive effects. Typically, substances in this drug class that are inhaled are chemicals that can be found in volatile solvents, aerosols, nitrites and gases that are often found in household, industrial and medical products.

Volatile solvents include paint thinners, paint removers, gasoline, glues, correction tape, and felt tip markers.

Aerosols include spray paint, spray deodorant, hairsprays, and fabric protector sprays.

Gases include medical anesthetics such as chloroform, halothane, and nitrous oxide, butane lighters and propane tanks.

Nitrates are prescription medications used for chest pains. They are also used recreationally to alter mood. Types of nitrates include cyclohexyl nitrate, amyl nitrate, and butyl nitrate.

Side-Effects of Using Inhalants

Because inhalants encompass a wide range of drugs and products, side effects will differ. In general, potential side effects include:




Liver & kidney damage





Heart failure

Loss of coordination

Slurred speech






How Common is Inhalant Use?

According to the 2018 National Survey on Drug Use and Health, about 2 million people over the age of 12 reported using inhalants. This is 0.7% of the population.1The average age that inhalants are first used is 17.4 years old.2

Drug Class: Steroids​

Steroids are a human-made drug that are used to treat low levels of steroid hormones in the body. Substances in this drug class are also used without a prescription to increase athletic and physical performance as well as to enhance physical appearance. The two main types of steroids are corticosteroids and anabolic steroids.

What Are Corticosteroids?

Corticosteroids are human-made medications that fight inflammation in the body. They mimic the hormone cortisol which helps the immune system to stop inflammation. Corticosteroids treat conditions that cause irritation and swelling such as:

  • Asthma
  • Lupus and other autoimmune disorders
  • Multiple sclerosis
  • Rashes and skin conditions like eczema
  • Rheumatoid arthritis

Side Effects of Corticosteroids?

Short-term side effects include:

  • Acne
  • Mood swings
  • Nausea
  • Puffy face
  • Trouble sleeping
  • Unusual hair growth
  • Weight gain

Long-term effects include:

  • Adrenal insufficiency
  • Brittle bones
  • Eye problems
  • Higher risk of diabetes
  • Muscle weakness

What are Anabolic Steroids?

Anabolic steroids are the human-made version of testosterone (a male sex hormone that helps with muscle growth). Anabolic steroids may be prescribed to people with testosterone deficiency, low levels of testosterone and to people who have lost muscle mass as a result of illness. Anabolic steroids are also widely abused because they help boost performance, muscle mass, and strength. Abuse is common amongst athletes who might take 100 times the dose that would be prescribed for medical purposes. Examples of anabolic steroids include nandrolone, oxandrolone, oxymetholone, stanozolol and testosterone cypionate.

Side-Effects of Anabolic Steroids


Fluid retention


Liver, kidney, and heart damage


Mood swings

Men may experience:

  • Breast growth
  • Infertility
  • Lower sperm counts
  • Smaller testicles

Women may experience:

  • Baldness
  • Changes in menstruation
  • Deeper voice
  • Facial hair growth

How Common is Steroid Use?

Because the 2018 National Survey on Drug Use and Health does not measure steroid use, it is hard to estimate how many people misuse steroids. Steroid misuse is most prevalent amongst men in their 20s and 30s.

Drug Class: Over-the-Counter Medication​

Over-the-counter medications are part of a drug class that are available for purchase without a prescription from a physician. This is because they are thought to be safe for use for the general public without needing to seek medical advice first. Medications in this drug class are typically purchased for pain relief, coughs, colds, the flu, diarrhea, heartburn, constipation, allergies, insomnia, and more.

What Commonly Known Drugs are OTCs?

Examples of OTC drugs include pain relievers such as acetaminophen (Tylenol), ibuprofen (Advil, Motrin), cough suppressants such as dextromethorphan (Robitussin) and antihistamines such as loratadine (Claritin). Some medications, although available as OTC medications, are kept behind the pharmacy counter and are dispensed by a pharmacist only. Such medications are typically ones that are known to have a history of abuse amongst users. An example is Sudafed, a medication used for sinus congestion that contains pseudoephedrine, which can be used to make meth.

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