Almost all people to some degree by the age of 80 will experience changes in their bodies. That change often results in the need for- medical treatment. But with all the drugs on the market, it can be confusing as to which one to choose. By using categories of drugs, we can better understand a medication classified by its chemical activity or by the condition that it treats.

The most common classifications include stimulants, depressants, hallucinogens, and opioids. However, there are many different categories of drugs that every healthcare professional needs to know.

To ensure the patient gets the correct prescription, these categories make it easier.

The Purpose of Drug Classification

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Four dominant sorting methods define and determine each of these particular groups.

First, we need to look at the therapeutic use of a specific drug, which means knowing the condition the drug treats. It's vital to group these into the same category in case a particular drug doesn't work. By understanding the medications listed in the group treat the same issue, it's faster to find an alternative replacement.

Next, are the drug's specific biochemical reactions and mode of action. A biochemical reaction is the transformation of one molecule to a different molecule inside of a cell. The mode of action is the condition of how the body will respond to a specific type of drug.

Last comes the breakdown of a drug's chemical structure. The chemical composition of a drug determines its physical properties and its capacity to interfere with normal biological processes. These properties include the absorption, distribution, metabolism, elimination, and toxicity of the drug.

These methods determine the categories of drugs and affect the medication's overall pharmacological activity.

The Most Commonly Prescribed Categories of Drugs

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Every time you take a type of drug, it will alter your body's current chemistry. And many medications may have more than one use and treat multiple conditions or disorders. Based on these diverse classification methods, some drugs might become grouped under more than one category.

Placing medications in particular categories of drugs helps the patient and the healthcare provider pinpoint directly what medication to try.

Here is a list of the most commonly prescribed categories of drugs.

Peripheral nervous system drugs

The central nervous system and the peripheral nervous system make up the two parts of the nervous system. The peripheral nervous system's job is to connect the central nervous system to the rest of the body.

These drugs fall under the peripheral nervous system category.

Cholinergic and anticholinergics

Cholinergic drugs are a wide variety of medications used to work on the peripheral nervous system of the body. These drugs work by mimicking or enhancing acetylcholine.

Think of acetylcholine as a mailperson between the two systems.

In other words, acetylcholine is released to create a series of intracellular signals that lead to the contraction of muscles. It plays a significant role in the control of involuntary bodily functions such as salivation and digestion. Acetylcholine can also link to the ability to learn, recollect memories, and the attention functions within the brain.

Just as cholinergic drugs increase acetylcholine, anticholinergics work to do just the opposite by blocking or decreasing it.

Anticholinergics are widely used to treat multiple conditions such as involuntary movements, gastrointestinal disorders, urinary incontinence, and Parkinson’s disease.

Central nervous system drugs

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The central nervous system is responsible for the moderation, process, and control over most of our daily bodily functions. This part of the nervous system includes nerves in the brain and spinal cord.

We use many different kinds of drugs to treat the conditions of the central nervous system. Some of the more well-known medications falling into this category are drugs for pain, like headache and muscle pains.

Depressants and stimulants

You will find the more commonly prescribed group in the categories of drugs in this collection. It deals with depressant medications such as sedatives, tranquilizers, and hypnotics.

Doctors prescribe these drugs in the treatment of anxiety, panic attacks, acute stress reactions, and sleep disorders.

Depressants are often confused with the term "antidepressants," which are given to decrease the symptoms of depression.

Depressant drugs act on the brain chemicals moderating communication between the brain cells, producing a drowsy or calming effect. However, despite the beneficial effects these drugs provide for such issues, they can become addictive and should be strictly monitored.

Stimulants are on the other end of the spectrum dealing with substances that stimulate the central nervous system increasing alertness. Unlike a depressant that slows you down, a stimulant does the direct opposite and is meant to speed you up.

In some cases, depressant and stimulant medications might switch and do the opposite of what's intended. When this occurs, the doctor needs to be aware, so she can prescribe the proper medicine to achieve the desired effect.

Opioids or narcotic analgesics

Narcotic analgesics fall under this group in the categories of drugs due to their effects on nerves in the brain. Also known as opioids, this group includes prescription drugs such as morphine, codeine, and oxycodone.

These drugs increase the amount of stimulation it takes for one to feel pain by attaching to the nerve receptors of the brain that control the body's recognition of pain.

However, while these drugs might improve your body's ability to deal with pain, they also weaken a person's perspective of suffering.

Narcotic pain medication should only be prescribed and used until the pain lessens or completely goes away. In some more severe cases where one suffers from chronic pain, it is essential to maintain proper drug management.

This type of medication is exceptionally addictive making it crucial that healthcare providers watch for warning signs of opioid dependency.

Penicillins and macrolides

Penicillins fall into a group of antibacterial drugs used to treat a wide range of infections caused by bacteria. These drugs work by killing or preventing the infected bacteria from further multiplying in the body.

Certain infections will require different specific forms of the antibacterial drug for treatment. A few commonly prescribed examples of penicillin medications would be amoxicillin, ampicillin, and nafcillin.

Each antibacterial drug in this family works in similar ways to treat specific infections but can cause different side effects. That said, those who are allergic to penicillin should not take any penicillin antibiotic such as amoxicillin.

Similar to penicillins, macrolides are a type of antibiotic used to treat, and sometimes prevent, a variety of bacterial infections. This type of antibiotic stops bacteria by preventing them from producing the proteins it needs to grow, eventually killing it.

It is good to note: Neither macrolide or penicillin drugs work to treat the common cold or the flu.

Drugs that affect the heart, blood vessels, and blood

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The body's advanced circulatory system is made up of the heart and an extensively branched network of blood vessels.

These blood vessels serve the primary function of transporting oxygen, nutrients, heat, and other essential substances throughout the body.

When it comes to the many categories of drugs, this category is one of the most important and severe. The medications that fall into this group focus on the safe regulation of the heart and continued blood flow.

Lipid regulators

Lipids are fatty acids.

We use lipid regulating drugs to treat diseases characterized by abnormal levels of lipids in the blood. These abnormal levels of lipids can produce raised cholesterol that can increase the risk of cardiovascular disease.

There are several different types of prescription lipid regulators that help lower levels in cholesterol. Statins are one of the most commonly used of these regulating drugs.

High doses of statins may also lower triglycerides, which are another type of blood fat in the prevention of coronary artery disease or stroke.

The use of lipid regulators is vast and has been used in other treatments such as osteoporosis, although the link between the two is still controversial.

ACE inhibitors

In the treatment of high blood pressure, ACE inhibitors are often the first drug that a doctor will prescribe. This group of drugs slows the activity of the enzyme ACE (angiotensin converting enzyme), which decreases angiotensin II.

By reducing the volume of blood flow, it lowers the blood pressure and helps the heart pump blood.

In addition to reducing high blood pressure, doctors prescribe ACE inhibitors to prevent, treat or improve the symptoms of:

  • Heart disease
  • Kidney disease
  • Hardening of the arteries

Which ACE inhibitor is best for you depends on your health and the condition being treated.

Calcium antagonists

The heart requires oxygen to pump blood, and it needs more oxygen the harder it works. When the heart is unable to receive enough oxygen equal to the workflow it becomes harder to pump blood. This pressure on the heart results in the occurrence of heart pain.

Calcium antagonists or calcium channel blockers dilate the arteries reducing pressure making it easier for the heart to pump blood. These drugs are also excellent medications to use for abnormal rapid rhythms in the heart.

Calcium antagonists closely resemble ACE inhibitors in the treatment of high blood pressure.


Often referred to as water pills, diuretics fall into the heart and blood categories of drugs. Doctors prescribe these medications for the treatment of many different complications such as congestive heart failure and high blood pressure.

These drugs help to lower blood pressure by reducing the amount of sodium and water in your body. They decrease the fluid in the rest of the body by increasing the flow of urine.

Additionally, diuretics are commonly used to treat certain types of kidney and glaucoma diseases.

Drugs for the endocrine system

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A network of glands make up the endocrine system and produce hormones controlling many bodily functions. It ranges from controlling how calories turn into energy, how your bones grow, to the way the heart beats.

The system also plays a vital role in the development of disorders, diseases, and complications throughout the body.

This group is made up of a wide range of medications covering several conditions. Diabetes, thyroid disorders, and remedies for hormonal alterations are some of the issues.

Antidiabetic drugs

As the name states, doctors use antidiabetic drugs for the treatment and management of diabetes. The primary role they play is in the stabilization and control of the blood glucose levels of people with diabetes.

There are several types of antidiabetic drugs, but the ones you will come across most often include Insulin and metformin. Depending on what type of diabetes the treatment is for will determine what antidiabetes drug is best to use.

Some antidiabetics like SGLT2 inhibitors not only benefit the glucose metabolism levels but they may promote weight loss and weight stabilization in some patients.

Hormonal contraceptives

Hormonal contraceptives deal with methods of birth control that act on the endocrine system.

These drugs regulate the change in hormone levels during a woman's cycle. The drugs do this by the use of synthetic hormones that mimic the estrogen and progesterone produced in the body.

The treatment can help prevent ovulation but can also prevent fertilized eggs from implanting into a woman's womb. Certain hormonal contraceptives work by making it harder for the sperm to move and reach the egg cell.

Anti-inflammatory, antiallergic, and immunologic drugs

Allergies can manifest with a wide variety of different symptoms, some more troublesome than others, but all cause much discomfort. Common symptoms, such as a runny nose or sneezing may be a more obvious symptom of allergies.

Extreme allergic reactions can often cause inflammation leading to chronic body pain and joint or muscle aches throughout the body. The repeated coughing or sneezing as a result of your allergies can also create additional soreness.

Lasting relief comes from using the correct medicines to help you treat your allergies, and reduce or eliminate your symptoms.


Antihistamines are commonly used to treat various allergic diseases that the body can develop. You can take medicine orally, with nasal spray, in eye drops, and even injected forms.

These drugs work by blocking the histamines causing your symptoms and providing symptom relief. The most common symptoms include sneezing, runny nose, itchy eyes, and hives.


Some severe reactions in the body can be life-threatening such as an unexpected negative or allergic response to an organ transplant.

Immunosuppressants, also known as anti-rejection drugs, can modify the body's response, either by reducing or suppressing the immune system.

Almost everyone who has any transplant must take immunosuppressants as directed by a doctor.

These drugs reduce the body's ability to reject foreign substances. However, by lowering the immune system's natural defense, this can also cause an increased chance of infections.

Drugs for bone and joint disorders

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Typically the cartilage in the body reduces friction levels in joints and protects them from wearing out. However, after years of repeated use sometimes the body can develop tissue damage or disorders which causes discomfort and pain.

Symptoms may include joint inflammation, joint deterioration, and limited movement.

The primary purpose of the medications within these categories of drugs is to relieve pain, help maintain joint flexibility, and optimize joint and overall function.


Antirheumatics are used in the treatment of rheumatoid arthritis supplemented by exercise and physical therapy.

These drugs can help slow the progress of the disease and reduce symptoms such as pain, stiffness, and inflammation. This treatment serves the primary goal of allowing the body to endure more normal daily activities without discomfort.

Antirheumatic drugs also work to prevent the effects of arthritis from getting worse by preserving the structure and function of the joints.

Each drug in this group works in different ways, with the possibility of toxicity.

Sometimes doctors have to prescribe different antirheumatics to find which works best and has the fewest side effects.

Additional Thoughts About the Different Categories of Drugs

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Even the slightest change in function of one part within the body can throw off your entire natural balance. Knowing the correct drug to treat such complications is essential for a healthy and happy life.

There are numerous categories of drugs and thousands of different drug classes and subclasses. These are just some of the most common.

Bringing order to chaos, we carefully sort medications into specific categories of drugs to better understand their uses and effects.

As our advancement and knowledge in medicine grow, so does the list of potent and more effective drugs. By grouping classes into the different categories of drugs, this ensures that the appropriate medication for treatment is always administered.

Do you know your way around these categories of drugs? We would truly appreciate your feedback!

If we missed anything or you have any suggestions, please feel free to let us know in the comments section below.