Opioids can cause effects such as drowsiness and slowed breathing, which may make them seem similar to depressants. Although opioids and depressants can affect the body in similar ways, opioids are a separate class of drugs.

Both types of substances can carry serious risks, including misuse, dependence, overdose, and dangerous breathing problems.

Understanding the differences between opioids and depressants can help people use these medications more safely and recognize potential risks. In this article, we'll compare opioids and depressants and explain their key differences.

What Class of Medications Do Opioids Belong To?

Although opioids share some effects with depressants, they work differently in the body. Opioids are also sometimes called narcotics, although healthcare professionals more commonly use the term opioids.

There are several types of opioids:

• Some, often called opiates, are made from natural substances found in the opium poppy plant.
• Synthetic opioids are made entirely in a laboratory.
• Semisynthetic opioids are partly made from natural opioid substances and partly made in a lab.

Examples of Opioids

There are more than 100 types of opioids. Some are prescription drugs for pain relief. Others are illegal drugs.

Common opioids include:

• Buprenorphine
• Codeine
• Fentanyl
• Heroin
• Hydrocodone
• Hydromorphone
• Methadone
• Morphine
• Oxycodone
• Oxymorphone
• Tramadol

What Are Depressants?

Depressants are a broad category of drugs that slow activity in the brain and nervous system. They can cause relaxation, drowsiness, and slower breathing. This category includes sedatives, hypnotics (sleep medications), and tranquilizers. Alcohol is also considered to be a depressant.

Common types of prescription depressants include benzodiazepines, nonbenzodiazepine sleep medications, and barbiturates.

Benzodiazepines

Benzodiazepines are usually prescribed for short-term treatment of conditions such as:

• Anxiety
• Panic attacks
• Acute (short-term) stress reactions
• Some sleep disorders

Common examples include diazepam and clonazepam.

Nonbenzodiazepine Sleep Medications

Nonbenzodiazepine sleep medications, sometimes called "Z-drugs," can help people fall asleep. Although they work differently from benzodiazepines, they can still cause drowsiness, dependence, and other serious side effects.

In rare cases, these medications can cause “complex sleep behaviors,” meaning someone may do activities while not fully awake, such as sleepwalking, eating, or driving.

Common examples include zolpidem and zaleplon.

Barbiturates

Barbiturates, such as phenobarbital and mephobarbital, are most often used to treat seizure disorders or help sedate people before medical procedures or surgery.

They are prescribed less often today because they have a higher risk of overdose and dangerous side effects than many newer medications.

How Opioids Work

Opioids work by binding to opioid receptors, which are proteins on nerve cells in the brain, spinal cord, and other parts of the body. These receptors normally help control pain, stress responses, and breathing. When opioids attach to these receptors, they can block pain signals from traveling through the spinal cord to the brain.

Many opioid receptors are found in parts of the brain involved in pleasure and reward. Because of this, opioids can cause feelings of relaxation, comfort, or euphoria (an intense feeling of pleasure). They can also affect thinking and alertness, making it harder for some people to concentrate or make decisions.

How Depressants Work

Depressants work by slowing activity in the central nervous system (CNS), which is why they're also called CNS depressants. The CNS includes the brain, spinal cord, and the brainstem. By slowing communication between the brain and body, depressants can make a person feel calmer, more relaxed, or sleepy.

Many depressants work by increasing the activity of a neurotransmitter (a chemical messenger in the brain) called gamma-aminobutyric acid (GABA). When GABA activity increases, brain activity slows down. This can reduce anxiety and promote relaxation and sleepiness.

Shared Effects of Opioids and Depressants

Opioids share some effects with depressants, which may lead some people to think opioids are a type of depressant. Both drug types can cause the following effects.

Sedation

Opioids can have a sedative or relaxing effect, similar to depressants like benzodiazepines, which are often prescribed for anxiety or sleep problems.

Both opioids and depressants can cause drowsiness and slower reaction times. Because of this, healthcare providers often recommend not driving or operating heavy machinery while taking these medications, even when they're used as prescribed.

Slowed Breathing

Both depressants and opioids also slow down your breathing rate. Opioids interact with opioid receptors in parts of the brainstem that control breathing, which can lead to shallow breathing and, in severe cases, loss of consciousness.

Depressants can also slow breathing and cause shallow or irregular breathing if taken at too high a dose. Overdosing on depressants can cause breathing to stop entirely.

Euphoria

Opioids can cause euphoria, which is an intense feeling of happiness or being "high," by triggering the reward system in your brain. Some depressants can also cause feelings of euphoria.

These pleasurable effects are one reason opioids and depressants may be misused.

Overlapping Risks of Opioids and Depressants

Opioids and depressants can have similar risks, including serious and sometimes life-threatening side effects. Before prescribing these medications, healthcare providers consider the potential benefits and risks and may monitor people closely while they are taking them.

Respiratory Depression

Respiratory depression means breathing becomes dangerously slow or shallow. This can happen with both opioids and depressants.

The risk is higher if someone:

• Takes more than prescribed
• Combines these drugs with alcohol or other sedating medications
• Has a health condition that affects breathing

When breathing slows too much, the body may not get enough oxygen or get rid of enough carbon dioxide. As carbon dioxide builds up in the blood, it can become toxic.

In severe cases, a person may stop breathing completely, which can be life-threatening.

Increased Tolerance

Over time, the body can develop tolerance to opioids or depressants. This means a person may need a higher dose to feel the same effects they felt before. Increasing tolerance can raise the risk of misuse, overdose, and other serious side effects.

Risk of Dependence

Both opioids and depressants can lead to physical dependence, meaning your body starts to feel like it needs them to function. If someone suddenly stops taking the medication or lowers the dose too quickly, withdrawal symptoms can occur.

Withdrawal symptoms from opioids may include:

• Sweating
• Muscle aches
• Anxiety
• Nausea
• Cravings

Depressants can also cause withdrawal symptoms and cravings, especially after long-term use.

Overdose

Taking too much of an opioid or depressant can lead to an overdose, which is one reason tolerance can be dangerous.

An opioid overdose is a medical emergency. It often causes very slow or stopped breathing, and a person may not wake up.

Warning signs of an overdose can include:

• Tiny (pinpoint) pupils
• Choking or gurgling sounds
• Blue, gray, or pale lips or fingernails, depending on skin tone

An overdose of depressants is also a life-threatening emergency with similar effects, like slow breathing, a slow heart rate, and loss of consciousness. Someone may be very hard to wake up, and their breathing may become very slow or stop.

It can be difficult or impossible to know how much of a drug could lead to an overdose, especially when some batches are stronger than others.

Interactions Between Opioids and Depressants

Combining opioids and depressants can greatly increase the risk of overdose and death because both can slow breathing and heart rate. For this reason, healthcare providers generally recommend avoiding this combination unless it is being carefully monitored.

It's important to tell your doctor about all medications and substances you use, including alcohol, over-the-counter medicines, supplements, and recreational drugs. This can help reduce the risk of dangerous drug interactions.

Talk to Your Doctor

If you have concerns about taking opioids or depressants, talk to your doctor. They can answer your questions about the risks, explain how to take the medication as safely as possible, and help you taper off opioids when the time is right.

Join the Conversation

On MyOpioidRecoveryTeam, people share their experiences with opioid use disorder, get advice, and find support from others who understand.

Have you or a loved one noticed drowsiness, slowed breathing, or other depressant-like effects from opioids? Let others know in the comments below.