How do opioids work?
How dangerous are they?
How can you spot an opioid overdose? 

As the opioid epidemic rages across America, there’s an increased focus on these substances in the news, on social media, and in public policy conversations. 

There’s a lot of misinformation, myth, and confusion surrounding opioids. Here are some frequently asked questions about prescription and illicit opioids, along with evidence-based answers.

What are the legitimate medical uses for opioids? 

There are appropriate and medically necessary uses for prescription opioids. They are effective in treating certain types of pain, or helping people recover from complex medical procedures. Pain resulting from things like broken bones and cancer can be effectively treated with opioids. 1,2

What’s more, one of the most effective treatments for opioid addiction actually involves the use of medications—some of which contain opioids—which can help ease withdrawal and reduce cravings to help maintain recovery.

However, opioids also have serious risks. That’s why opioid prescriptions should always be both personalized to suit each patient’s unique needs, as well as carefully monitored by health care providers.

12 Questions to Ask Your Doctor Before Taking Opioids

Print out this list of questions as a starting point when talking to your doctor.

Download the guide

Why is opioid overprescribing dangerous?

Opioids are highly addictive. A patient who is taking opioids can develop both tolerance and dependence quickly. Patients may find themselves needing to take more and more of the drug to experience the same pain relief it once provided. And if they try to stop taking the drug, or to reduce their dosage, they may experience painful withdrawal symptoms. While dependence itself isn’t a problem (for example, diabetes patients are “dependent” on their insulin), these circumstances can lead to accidental overdose, misuse, or addiction. 3,4

Using opioids while taking other medications (like benzodiazepines) or using other substances (like alcohol) also increases risk of accidental overdose. Prescription Drug Monitoring Programs can help keep doctors informed about their patients’ prescribing history—but these programs aren’t mandated in every state. Learn more about PDMPs.

Opioid overprescribing is dangerous to the public, too. According to the Centers for Disease Control (CDC), the number of opioids prescribed in the U.S. has quadrupled in the past 15 years, even though there's been no change in the amount of pain American patients report.5 In 2013, health care providers wrote enough opioid prescriptions for every adult American to have their own bottle of pills. And in 2016, 3.3 billion pills were left unused by patients, making them available for potential diversion and misuse.6 

Why would someone move on from pills to heroin?

According to the American Society of Addiction Medicine, four out of five people who are addicted to heroin report that their addiction began with prescription pills.7 These opioid pills either come from friends, family, or personal prescriptions.8 Heroin is an opioid, too, and affects the body and brain the same ways that prescription opioids do. Heroin is cheaper, and widely available from street drug dealers. So as a person’s addiction escalates, heroin may become easier to acquire than prescription pills.


What are “abuse-deterrent formulations” of opioids?

Abuse-deterrent formulations (or ADFs) are engineered to prevent users from crushing or dissolving the pills.

People who misuse opioids often crush pills up, then snort or inject them. This is because the high is more immediate and more potent when the drugs enter the body this way. Abuse-deterrent opioids seek to make it harder or impossible for people to do this. However, in terms of potency and effects, ADFs are no different from regular opioids.

Calling these formulations “abuse-deterrent” is confusing at best, misleading at worst. There’s nothing in the chemical make-up of these pills that make them less addictive. These abuse-deterrent pills can still foster addiction and be misused, even when taken orally.9 

“Opiate” vs. “Opioid”? What’s the difference?

The word “opiate” applies specifically to drugs directly derived from the poppy plant. Heroin, for example, is an opiate. But partially or fully synthetic opioids, like prescription OxyContin or illicit fentanyl, are made in a lab. The word “opioids” includes all formulations of these drugs: plant-derived, semi- and fully-synthetic.10  

How do opioids work?

These drugs are similar to other chemicals in our bodies that attach to opioid receptors which are found in our brains. Opioid drugs bond to these receptors throughout the nervous system, and this process can have three main effects:11 

  • It decreases feelings of pain 
  • It creates feelings of pleasure and relaxation
  • It slows automatic processes in our body like breathing

What are the side effects of taking opioids as prescribed?

Besides the risk of addiction and misuse, using opioids as directed by your doctor can have many other side effects, including:12 

  • Dizziness
  • Constipation
  • Nausea

What are the effects of misusing opioids?

When someone is misusing opioids, that means they’re taking prescription opioids without a prescription, taking the wrong dosage of prescribed opioids, or using illicit opioids. 

This misuse creates intense feelings of euphoria. A person misusing opioids may seem drowsy or disoriented, with slurred speech or slowed movements. Long-term opioid misuse often leads to addiction: uncontrollable drug-seeking, no matter the consequences.11,12


What is opioid withdrawal like?

It’s a painful, whole-body experience. According to NIDA, symptoms include restlessness, muscle and bone pain, insomnia, diarrhea, vomiting, cold flashes with goose bumps (“cold turkey”), and leg movements. These are at their most intense within 24-48 hours after the last dose wears off, and subside after about a week.13 

What happens when someone overdoses on opioids?

During an opioid overdose, a person’s breathing becomes dangerously slow, and then stops completely. With the opioid suppressing neurological signals, the heart rate slows down, too. An opioid overdose can do permanent brain or nerve damage, and of course can be fatal.

Signs that someone is overdosing on opioids include:14 

  • Shallow breathing, or no breathing at all
  • Blue or grey lips or fingertips
  • Floppy arms or legs
  • Snoring or gurgling
  • Unresponsive, can’t be woken up

Mixing opioids with other substances, especially sedatives like alcohol or benzodiazepines, increases overdose risk.

Naloxone is a medication that can reverse an opioid overdose in minutes. Learn more about naloxone.


OxyContin (Oxycodone) 
OxyContin is a brand-name, synthetic opioid medication. Oxycodone is the generic formulation.

The difference between the two is that OxyContin is intended to function as an extended-release formulation, while oxycodone is only available in an immediate-release formulation.

OxyContin’s ability to function as advertised has been called into question, and the subject of lawsuits.17

OxyContin is commonly prescribed after complex medical procedures, like surgeries.

Vicodin (Hydrocodone)18 
Vicodin is a brand-name, synthetic opioid medication which also contains acetaminophen. Hydrocodone is a generic formulation of Vicodin.

Codeine is a naturally derived opiate. It is commonly prescribed as a cough suppressant.  

Morphine is one of the oldest opioid classifications. It is often used in hospitals to relieve severe pain.

Heroin is the most common illicit opioid. It is looks like a white or brown powder, or sometimes a black sticky substance (“black tar heroin”). 

Fentanyl & Carfentanil
These are powerful synthetic opioids. According to the Drug Enforcement Agency (DEA), fentanyl is 30-50 times deadlier than heroin, and Carfentanil is 100 times deadlier than fentanyl.20  

Carfentanil is most frequently used as a sedative for large animals like elephants. 

Fentanyl can be legitimately used in medical settings for pain management. It’s an extremely powerful synthetic opioid. It can be prescribed to treat pain, and is known by brand names Actiq, Duragestic, and Sublimaze.

These opioids can also be illicitly produced in labs. Lately, street drug supplies are increasingly laced with fentanyl, which has greatly contributed to our country’s overdose epidemic.22 

Though fentanyl is highly potent and very dangerous, the hysteria surrounding the drug is often unfounded. Scientists say that it’s impossible to overdose on fentanyl just by touching it, for example.23

Methadone & Buprenorphine (Suboxone)24
These opioid medications are used to treat opioid use disorder. When taken as directed by a doctor to treat OUD, these medications do not create physical impairments or cause a high. These medicines ease withdrawal symptoms and allow people with OUD to work, drive, and participate in their family life.

As with all opioids, it is possible to misuse buprenorphine or Suboxone by taking these pills without a prescription or a doctor’s supervision.

1. NIDA. What Are Prescription Opioids? January 2018.
2. CDC. Prescription Opioids. August 2017.
3. CDC. Prescription Opioids. August 2017.
4. NIDA. What Are Prescription Opioids? January 2018.
5. CDC. Understanding the Epidemic August 2017.
6. Pacira Pharmaceuticals. The United States for Non-Dependence: An Analysis of the Impact of Opioid Overprescribing in America. September 2017.
7. American Society of Addiction Medicine. Opioid Facts & Figures. 2016.
8. NIDA. Prescription Opioid Use Is A Risk Factor For Heroin Use. January 2018.
9. Theodore J. Cicero, PhD, Matthew S Ellis, MPE. Abuse-Deterrent Formulations and the Prescription Opioid Abuse Epidemic in the United States. JAMA Psychiatry, May 2015.
10. NIDA for Teens. What Are the Different Types of Opioids? July 2014.
11. NIDA for Teens. How Do Opioids Work? February 2018.
12. NIDA. What Are Prescription Opioids? January 2018.
13. NIDA. What Are the Long-Term Effects of Heroin Use? January 2018.
14. International Overdose Awareness Day. What Is An Overdose?
15. NIDA for Teens. What Are the Different Types of Opioids? July 2014.
16. SAMHSA. Opioids. February 2016.
17. New York Times. In Guilty Plea, OxyContin Maker to Pay $600 Million. May 2007.
18. Vicodin.
19. Codeine.
20. DEA. Fentanyl FAQ.
21. NIDA. What is Fentanyl? January 2018.
22. DEA. 2017 National Drug Threat Assessment. October 2017.
23. ACMT and AACT Position Statement: Preventing Occupational Fentanyl and Fentanyl Analog Exposure to Emergency Responders
24. SAMHSA. Medications Used in MAT. September 2015.