Fentanyl Overdose
Learn the possible signs of a fentanyl overdose, how to respond with naloxone and emergency care, and how ongoing treatment can reduce future risk.
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How to Recognize a Fentanyl Overdose
A fentanyl overdose can slow or stop breathing. Possible signs include being unable to wake up, slow or absent breathing, gurgling sounds, discolored lips or nails, and very small pupils. You do not need to see every sign. If you suspect an overdose, give naloxone if available and call 911 immediately.[1]
Suspected overdose needs immediate action. Use available naloxone and call 911. Follow dispatcher instructions to help breathing. Repeat naloxone after 2 to 3 minutes if normal breathing has not returned, following product directions. If breathing normally but still unconscious, place the person on their side. Remain with them until emergency responders arrive.[1][2][3]
Fentanyl acts on opioid receptors, structures in the nervous system that respond to opioids. During an overdose, these effects can suppress the body’s drive to breathe. This is called respiratory depression. Naloxone blocks opioid effects and can restore breathing. You do not have to identify the exact drug before helping.[4][1]
- Breathing and responsiveness matter. Do not wait for pinpoint pupils, skin discoloration and unresponsiveness to appear together.[1]
- Naloxone works against fentanyl. Standard-strength naloxone works in most fentanyl overdoses, although additional doses may be needed. Give the available product and follow its instructions.[5]
- Surviving an overdose is an opportunity for ongoing care. Medication treatment for opioid use disorder is associated with lower overdose risk. Naloxone rescue and ongoing treatment serve different purposes.[6]
Signs of a Possible Fentanyl Overdose
Small pupils, reduced breathing and unresponsiveness are sometimes called the opioid overdose triad. These signs can vary. Someone who cannot wake up or has slow, shallow or absent breathing needs immediate help. Normal-looking pupils or skin color do not establish that the person is safe.[1]
Breathing and Responsiveness
A snoring or gurgling sound from someone who cannot wake up can be an overdose sign. Do not assume they are sleeping safely. Other possible signs include a limp body and blue or discolored lips, gums or fingertips. Tell the emergency dispatcher what you can see and hear.[1][3]
The table is a guide to observations, not a test that can rule out an overdose. If you suspect an overdose, give naloxone if available and call 911. You do not need to count breaths to a particular cutoff or wait for every sign.[1]
| What you notice | How to respond |
|---|---|
| Cannot wake up when called or gently shaken | Treat a suspected overdose as an emergency. Give naloxone and call 911.[1] |
| Slow, shallow, gasping, gurgling or absent breathing | Get emergency help and follow dispatcher instructions for breathing support or CPR.[1][2] |
| Very small pupils, limpness or discolored lips and nails | These can support concern for overdose. Their absence does not rule one out.[1][3] |
| Drowsiness or a brief response, followed by worsening breathing or unresponsiveness | Do not rely on a moment of wakefulness as reassurance. Seek emergency help for suspected overdose.[1][3] |
What to Do During a Fentanyl Overdose
Give naloxone and call 911 immediately. If another person is present, ask them to call while you give naloxone. Tell the dispatcher your location and whether the person is breathing or responding. You can help even if you do not know what they took.[1]
Give Naloxone and Support Breathing
Keep the dispatcher involved while you follow these steps. A response to naloxone does not remove the need for emergency medical care.[1]
- Use the product you have according to its instructions. Naloxone comes as nasal spray and injectable products. The devices and directions differ.[1]
- Give another dose if needed. If normal breathing has not returned after 2 to 3 minutes, give another dose according to the instructions. Continue following the product directions and dispatcher guidance.[1]
- Follow the dispatcher’s instructions for rescue breathing or CPR. Naloxone does not replace breathing support or emergency medical care.[2]
- Use the recovery position when appropriate. If the person is breathing normally but remains unconscious, place them on their side to reduce choking risk. Keep watching breathing.[3]
- Stay until emergency responders arrive. Even if the person wakes up, naloxone’s effect can wear off and overdose symptoms can return.[3]
The immediate goal is normal breathing. A pharmacology review by Saari and colleagues emphasizes restoring breathing rather than making someone fully awake. That distinction helps explain why you should report breathing changes to the dispatcher rather than judge the response only by whether the person opens their eyes.[7]
Lack of oxygen can injure the brain. A systematic review found reports of brain injury and problems with memory or thinking after opioid overdose, but the studies had substantial limitations. It could not establish how often these outcomes occur. Prompt emergency care matters, and persistent problems after an overdose deserve medical assessment.[8]
Concerns About Calling for Help
Most states have Good Samaritan laws that may protect people seeking emergency overdose help from some drug-related penalties. Protections vary, so this is not a promise of immunity. Do not delay emergency care while trying to determine the exact drug involved or whether the person has every overdose sign.[1]
In a New York study of people trained to use naloxone, accurate knowledge of the state’s Good Samaritan law was associated with greater odds of calling emergency services during a witnessed overdose. This was an observational study in one state, not proof that every law offers the same protection.[9]
After Naloxone Works
Naloxone can trigger sudden, sometimes severe withdrawal in someone whose body is dependent on opioids. Withdrawal means symptoms that occur when the body loses an opioid it has adapted to. Symptoms after naloxone can include vomiting, sweating, body aches and agitation. Tell the dispatcher about worsening symptoms and continue watching breathing.[10]
Do not assume that withdrawal symptoms or waking up mean the emergency is over. Naloxone is temporary, and other drugs may also be involved. Stay with the person and wait for emergency medical help.[3][2]
If you are unsure, give naloxone. The FDA explains that naloxone generally has no effect or causes no additional harm when opioids are absent. That does not mean all medication use is risk-free. The possibility of withdrawal is not a reason to withhold naloxone during a suspected opioid overdose.[3][10]
Why Fentanyl Can Cause a Rapid Overdose
Fentanyl is a potent synthetic opioid, meaning it is made in a laboratory. Prescribed fentanyl has medical uses for severe pain. Illegally made fentanyl drives much of the overdose crisis and may be present in drugs or pills without the person knowing. Its effects can begin quickly, and even a small amount can cause a fatal overdose.[5]
Potency does not tell you a safe dose of an unregulated drug. Contents and concentration can vary, and a person’s response also matters. A pill’s color, shape or stamp cannot establish what it contains.[5]
Chest Stiffness and Other Complications
Fentanyl can cause muscle rigidity, including severe stiffness of the chest and breathing muscles. This is sometimes called wooden chest syndrome. A clinical review describes how this can interfere with breathing. The review does not establish how often it occurs in community overdoses, so it should not be treated as a sign that must be present.[11]
Researchers have proposed that mechanisms beyond ordinary opioid effects may contribute to fentanyl’s toxicity. These remain mechanistic proposals rather than proof of why a particular community overdose responds poorly.[12] Those proposals do not change the bystander response: give naloxone, call 911, and follow instructions to support breathing. Standard-strength naloxone remains effective in most fentanyl overdoses.[5]
Related drugs, called fentanyl analogs, can also enter the illicit supply. Carfentanil is one example that is more potent than fentanyl. A test strip may not detect every related drug.[5]
What Raises the Risk of a Fentanyl Overdose
Fentanyl exposure can be intentional or unexpected. Both deserve practical prevention and access to treatment. People may know that a drug contains fentanyl without knowing its strength or other ingredients.[5][13]
Counterfeit Pills and an Unpredictable Supply
Illegally made fentanyl may be mixed with heroin, cocaine or methamphetamine, or pressed into counterfeit pills that resemble prescription medicines. Someone taking a pill sold as oxycodone or an anxiety medicine may not know it contains fentanyl. Appearance, taste and smell cannot reliably identify it.[5]
A Washington, D.C., forensic study examined pills submitted over 56 months and found fentanyl in counterfeit tablets, often blue pills marked to resemble prescription oxycodone.[14] This describes a particular set of submitted evidence, not the probability that any pill nationwide contains fentanyl.[14]
Interviews with 22 people in Arizona during 2020–2021 described counterfeit fentanyl pills called “blues” or “dirty oxys,” often smoked.[13] Participants described reasons for using them, including availability and perceptions of risk. This small qualitative study helps explain people’s experiences, but it cannot show how common those experiences are nationally.[13]
Fentanyl test strips can provide useful information, but a negative result does not guarantee that a drug is free of fentanyl. Fentanyl may be unevenly distributed, and the tested sample may miss it. Strips do not measure the amount or establish that a drug is safe. Keep naloxone available and avoid using alone regardless of the result.[15]
Lower Tolerance After Time Away
Tolerance means the body has adapted so that a drug has less effect than before. Tolerance can fall after stopping opioids. Returning to a previously used amount can therefore cause overdose. Ask for a medication and overdose-prevention plan before leaving detox, hospital care or incarceration.[16][6]
Research shows why transitions out of incarceration deserve attention. An Oregon cohort found the highest overdose rate in the first two weeks after release. An analysis combining 18 cohorts from eight countries found the highest overall death rate in the first week, with alcohol and other drug poisoning the leading cause in that period.[17][18]
These studies involved different places and historical periods. They were not fentanyl-only studies, and their rates should not be used to predict an individual person’s outcome. They support arranging care, medication access and naloxone before a gap in support occurs.[17][18]
Mixing Drugs, Using Alone and a Prior Overdose
Combining opioids with alcohol or sedating medicines such as benzodiazepines increases overdose concern. Benzodiazepines are medicines sometimes prescribed for anxiety or sleep. Tell clinicians about all substances and prescriptions so they can help reduce risk without abrupt, unsupervised medication changes.[3][6]
Two observational studies found higher risk of overdose death among patients receiving opioids with sedatives: one involved Washington Medicaid patients with pain, and another involved veterans with post-traumatic stress disorder. These findings do not establish a single risk multiplier for everyone using illicit fentanyl.[19][20]
Using alone means no nearby person may be able to give naloxone or call for emergency help. Having someone able to respond can reduce that risk, but does not guarantee survival. A previous overdose is also a reason to seek prompt follow-up and discuss ongoing treatment, even if the person feels better.[2][21]
How to Get and Use Naloxone
Naloxone is available in over-the-counter nasal sprays, including Narcan. Other products may require a prescription. Pharmacies, local health departments and community harm-reduction programs can help you find it. Some programs provide it free. Ask about cost and availability in your area.[3][1]
Learn the directions for the product you carry before an emergency, and show friends or family where it is kept. A pharmacist or local naloxone program can explain how to use it. Keeping it accessible helps another person respond if you cannot.[1]
What Community Naloxone Research Shows
A Massachusetts study covering 2002–2009 found lower opioid overdose death rates in communities with overdose education and naloxone distribution programs. A systematic review of 22 observational studies also supported take-home naloxone programs. These studies support community access, while their observational designs and historical settings limit causal and fentanyl-specific conclusions.[22][23]
In a Maryland series of 78 reported bystander naloxone cases, about three quarters of recipients were breathing, talking or walking within minutes.[24] Two people died.[24] This illustrates that bystanders can help, but the series cannot promise a particular result in today’s fentanyl supply or replace emergency medical care.[24]
When Xylazine Is Also Involved
Xylazine is a sedative approved for veterinary use, not for people. It is not an opioid, so naloxone does not reverse its effects. Still give naloxone during a suspected overdose because an opioid may also be present. Call 911 and follow breathing-support instructions.[2]
CDC surveillance found increasing xylazine detection in deaths involving illegally made fentanyl during 2019–June 2022 across participating jurisdictions. That historical finding is not a current national estimate of the drug supply. The practical point remains that sedation and breathing problems can persist after naloxone when other substances are involved.[25][2]
Preventing the Next Overdose
After emergency treatment, ask about medication for opioid use disorder, take-home naloxone and a follow-up appointment. Opioid use disorder is a treatable condition involving a pattern of opioid use that causes harm or distress. Medication treatment is associated with lower overdose risk and overall mortality.[6][5]
A Connecticut study followed 4,089 people after an overdose-related hospital or emergency visit in 2016–2017.[21] Methadone or buprenorphine treatment was associated with a lower risk of another overdose over the next year. However, the study did not find a statistically significant change in fatal overdose risk for those treatments. It was observational and cannot prove cause and effect.[21]
Buprenorphine and methadone are medications that reduce opioid cravings and support ongoing treatment. Methadone also relieves withdrawal. Another option, naltrexone, blocks opioid effects and requires an opioid-free period before starting. A clinician can help choose and safely begin a medication. Detoxification alone is not recommended treatment for opioid use disorder because of return-to-use and overdose risks.[6]
Fear of fentanyl withdrawal is a reason to ask for help managing symptoms. It does not mean you must complete a separate detox program before discussing ongoing treatment. Learn about fentanyl detox and withdrawal care and medications for addiction treatment, or read the broader fentanyl addiction guide.[6]
Our treatment centers directory can help you explore care options. Ask whether a program offers medication for opioid use disorder and follow-up after overdose. For counseling support, see online therapy options. Counseling can support recovery, but emergency overdose care requires immediate medical help.[6]
For substance use treatment referrals in the United States, call SAMHSA at 1-800-662-HELP (4357) or use FindTreatment.gov. For suicidal thoughts or a mental health crisis, call or text 988. A suspected overdose, suicide attempt or immediate physical danger requires 911.[5]
Frequently asked questions
What Are the Signs of a Fentanyl Overdose?
How Much Naloxone Do You Need for a Fentanyl Overdose?
Give one dose according to the product instructions and call 911 immediately. If normal breathing has not returned after 2 to 3 minutes, give another dose according to those instructions. Follow the dispatcher’s guidance for breathing support or CPR and stay until emergency help arrives, even if the person wakes up.[1][2]
Can You Reverse a Fentanyl Overdose?
Naloxone can reverse an opioid overdose, including one caused by fentanyl. Standard-strength naloxone works in most fentanyl overdoses, although additional doses may be needed. It is temporary treatment. Give it promptly, call 911, follow dispatcher instructions to support breathing, and stay with the person until help arrives.[5][3]
Why Is Fentanyl So Deadly?
Fentanyl is a potent opioid whose effects can start quickly. Too much can slow or stop breathing. Illegally made fentanyl may be present in counterfeit pills or other drugs without the person knowing, and contents can be unpredictable. Prescribed fentanyl has medical uses for severe pain, but also carries overdose risks.[5]
Can You Overdose on Fentanyl Without Knowing You Took It?
Yes. Fentanyl may be mixed into heroin, cocaine, methamphetamine or counterfeit pills without the person knowing. Some people also use fentanyl intentionally. A pill’s appearance cannot establish its contents, and a negative fentanyl test strip does not guarantee that fentanyl is absent or that a drug is safe.[5][15]
What Should You Do After Someone Survives a Fentanyl Overdose?
Stay for emergency medical care even if naloxone wakes the person. Breathing problems can return. After emergency care, ask about take-home naloxone, medication for opioid use disorder and follow-up. Medication treatment is associated with lower overdose risk, while detox alone is not recommended treatment for opioid use disorder.[3][6]
Explore our treatment centers directory, fentanyl detox guide and medication treatment information. Our online therapy options provide a separate route to counseling support.
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