20 Medication-Related Terms to Know

There are many medication-related terms that healthcare providers use when talking about medications. These terms can be confusing to understand, especially without any experience. 

Once you’re able to understand this terminology, things may start to make more sense. A better understanding of your medications can empower you and help you make informed healthcare decisions. 

If you want to know more about terminology related to your medications, here are some definitions that can help you.

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Glossary of medication-related terminology

Browse these 20 common terms listed below in alphabetical order.

A

Adverse event

An adverse event is an unexpected effect that may be caused by a medication. Some adverse events are mild, whereas others may be severe or life-threatening. For example, an allergic reaction to an antibiotic is considered an adverse event.

Agonist

An agonist is a substance that binds to certain targets in your body to activate them. This results in a number of actions within your body (e.g., pain or anxiety relief). Think of an agonist like a key that fits into a lock and opens a door.

Some medications are agonists. This means they can activate certain targets and cause effects in your body. They can be full agonists, causing a maximum effect after binding to a target. They can also be partial agonists, which means they don’t cause as much of an effect.

For example, albuterol (ProAir, Ventolin) binds to and activates targets in your airways. This helps you breathe easier during an asthma attack.

Analgesic

Analgesics are also known as pain-relief medications. There are many kinds of analgesics, and they work differently in your body to relieve pain. Some are available over the counter (OTC) without a prescription. Others you can only get with a prescription. 

Some common OTC analgesics include acetaminophen (Tylenol) and ibuprofen (Motrin, Advil). Analgesics like celecoxib (Celebrex) require a prescription.

Anaphylaxis

Sometimes allergic reactions can become very severe and life-threatening. This is called anaphylaxis, and it can be caused by certain foods, medications, and other things you’re allergic to. Symptoms can happen very quickly, including difficulty breathing, swelling of your throat, and dizziness. 

Anaphylaxis is a potentially life-threatening situation, so you’ll need to get emergency medical attention right away. That’s why it’s important to let your provider know if you’re allergic to anything, including medications, materials (e.g., latex), or food.

Antagonist

An antagonist is a substance that binds to certain targets in your body but doesn’t activate them. It can also block other substances that bind to the same target. This prevents a number of actions from happening in your body. Think of an antagonist like a key that fits into a lock but prevents you from opening the door.

Some medications are antagonists. This means they block certain targets, preventing effects in your body. In fact, they are sometimes referred to as “blockers.” For example, metoprolol (Lopressor) blocks certain targets in your heart. This slows it down, which can help alleviate chest pain.

B

Boxed warning

Medications are approved by the FDA to ensure their safety. A boxed warning (also called black box warning) is the FDA’s strongest warning for a medication. It calls attention to any potentially serious side effects or if there’s any limitations to who should use the medication. 

Brand medication

A brand medication is usually the first of its kind or the “original” version of a medication. Because of this, it’s usually protected by patents. This means that no other pharmaceutical companies can manufacture a medication like it for a period of time. Once its patent expires, other companies can make generic versions. However, brand-name medications are usually more expensive.

C

Contraindication

There are certain circumstances when a medication shouldn’t be used. This is because it can be harmful when used in these circumstances. This is called a contraindication. 

There are two types of contraindications:

• Relative contraindication: If the benefits outweigh the risks, a medication may be used with caution. For example, some medications can cause liver damage. A healthcare provider may decide to use it with caution for someone with pre-existing liver damage.

• Absolute contraindication: This can cause a life-threatening situation. Anything that falls under an absolute contraindication should be avoided. For example, certain medications are contraindicated during pregnancy because they can harm an unborn baby.

Controlled substance

Some medications are considered to be controlled substances. This is because they carry a potential risk of physical and mental dependence. Because of this risk, they have restrictions on how they’re prescribed and filled at a pharmacy. 

Controlled substance medications can be broken down into several categories (called schedules) depending on their risk for misuse. These range from highest to lowest potential risk and include schedules I, II, III, IV, and V. Schedule I has the highest potential risk and Schedule V has the lowest potential risk.

D

Dose and dosage

A dose is a specific amount of medication that you take at one time, such as a 500 mg tablet. A dosage includes the dose, frequency, and how long you’re taking it. For example, your dosage might be 500 mg by mouth twice daily for 7 days. Typically, the dosage is what’s written in the directions area of a prescription label.

G

Generic medication

A generic medication is modeled after a brand-name medication. But it can differ in shape, color, and inactive ingredients. For most medications, this shouldn’t affect how it works. You should expect the same clinical benefit when taking a generic version of a brand-name medication in most cases. Plus, it’s usually less expensive than its brand-name version.

I

Interaction

A drug interaction is a reaction between a medication and something else. This can include:

• Another medication or supplement: Some medications and supplements can interfere with how another medication works. These interactions can also result in worse side effects from treatment.

• Food or beverage: Some foods and beverages can affect how your body absorbs a medication (e.g., dairy products). They can also interfere with how your body gets rid of medication (e.g., grapefruit juice).

• Health condition: Some medications can worsen certain health conditions. For example, people with high blood pressure shouldn’t use certain OTC medications because they can raise blood pressure.

Medication interactions can be harmful. So, it’s important that your healthcare provider and pharmacist are aware of your health conditions and any other medications you’re taking. Be sure to follow their instructions for how to take your medication safely and avoid interactions.

L

Loading dose

Some medications need to reach a certain level in your body to be effective. This is especially important when you need them to work quickly. A loading dose is when you initially take a higher dose to start. After that, you’ll usually take a lower dose for the remainder of treatment. 

For example, you may be prescribed azithromycin (Z-Pak) for 5 days when you’re sick. The first dose is higher than the doses you’ll take on the other 4 days. This is to help the medication reach effective levels faster. 

M

Maintenance dose

A maintenance dose is the usual dose that you’ll take when you’re on a medication. It may be the dose you take after a loading dose. Or it may be the dose you stay on after gradually raising your dose at the start of treatment. The maintenance dose ensures that the amount of medication in your body constantly stays at an effective level. 

Maximum dose

Medications usually have a recommended dosage range. This is the range that’s been determined to be safe and effective for most people. The maximum dose is the upper limit of the recommended dosage range. Doses above the maximum dose may result in more side effects without additional benefits.

Metabolism

When you take a medication, it gets processed by your body. This process is called metabolism. Medications are chemically changed during metabolism. Sometimes this is required for them to work. Other times this makes them easier to be eliminated from your body. 

Metabolism usually happens in the liver. But it can also happen in other areas, including the gastrointestinal (GI) tract (stomach and intestines) and kidneys.   

P

Placebo

When medications are being studied in clinical trials, they’re sometimes compared to a substance that doesn’t contain any medication. This is called a placebo. Some studies use placebos like sugar tablets or salt water.

Prodrug

Some medications aren’t absorbed very well by your body. And others may work better if they’re able to reach a certain area in your body (e.g., intestines). Scientists will sometimes formulate medications to help solve these issues. These medications are called prodrugs. 

Prodrugs are medications that don’t have clinical effects on their own. But they turn into their active form once they enter your body or reach a target area. 

Once the prodrug becomes active, it’s able to start working. For example, omeprazole (Prilosec) is a prodrug. It only becomes active once it reaches your gut to relieve heartburn and treat gastroesophageal reflux disease (GERD). 

Prophylaxis

Prophylaxis is measures taken to prevent a condition. It’s also known as prevention. There are three types of prophylaxis: primary, secondary, and tertiary: 

• Primary: preventing a condition before it happens. For example, pre-exposure prophylaxis (PrEP) is recommended for people at high risk for HIV infection.  

• Secondary: preventing a recurrence or worsening of a condition you already have. For example, daily exercise and a healthier diet can prevent further heart attacks or strokes.

• Tertiary: managing a condition to either slow or stop its progression. For example, chemotherapy can help slow the growth of a cancerous tumor.

R

Receptor

Receptors are proteins that are found on the outside or inside of a cell. They are responsible for receiving and transmitting signals, and they can be activated or blocked. This can control different effects in your body. Medications usually work by binding to different receptors.

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Written by:

Christine Pham, PharmD

Christine Pham is a post-doctorate fellow in clinical development at Merck. She earned her doctorate of pharmacy from the University of California, San Francisco (UCSF) and holds a bachelor’s degree biochemistry from UC Riverside.

Edited by:

Alyssa Billingsley, PharmD

Alyssa Billingsley, PharmD, is the director of pharmacy content for GoodRx. She has over a decade of experience as a pharmacist and has worked in clinical, academic, and administrative roles.

Reviewed by:

Christina Aungst, PharmD

Christina Aungst, PharmD, is a pharmacy editor for GoodRx. She began writing for GoodRx Health in 2019, transitioning from freelance writer to editor in 2021.

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