Barbiturate-Related Asphyxia: The Dangers Explained
What barbiturate-related asphyxia is, how barbiturates suppress breathing, why overdose is so dangerous, and how to get help.
Clinically reviewed by Dr. Ponlawat Pitsuwan, Physician and Addiction Medicine Specialist, Phuket Island Rehab.
Barbiturate-related asphyxia refers to a lack of oxygen (asphyxia) caused by barbiturates suppressing a person’s breathing. Barbiturates are a class of sedative drugs that depress the central nervous system, and in high doses or overdose they can dangerously slow or stop breathing (respiratory depression), so that the body does not get enough oxygen; this can lead to asphyxia, brain damage from lack of oxygen, and death, and it is the main way barbiturate overdose kills. This danger is heightened by the fact that barbiturates have a narrow margin of safety (the difference between an effective and a fatal dose is small), and it is dramatically increased when barbiturates are combined with other central nervous system depressants such as alcohol or opioids, which also suppress breathing. Deeply sedated by barbiturates, a person may also be at risk of asphyxia from their airway becoming blocked or from choking, for example on vomit, because they cannot protect their airway. Barbiturate overdose is a life-threatening medical emergency. Because of these dangers, anyone dependent on barbiturates should never stop suddenly (withdrawal can also be dangerous) and should seek medically supervised treatment. If you or someone you know is misusing or dependent on barbiturates, help is available, and addiction is treatable.
What is barbiturate-related asphyxia?
Barbiturate-related asphyxia refers to asphyxia, a dangerous lack of oxygen reaching the body’s tissues, caused by barbiturates suppressing a person’s breathing. To understand it, it helps to know what barbiturates are and how they act. Barbiturates are a class of sedative-hypnotic drugs that depress (slow down) the central nervous system, producing effects ranging from sedation to deep anaesthesia. Among the functions the central nervous system controls is breathing, and barbiturates, in high enough doses, can suppress the drive to breathe. When breathing is dangerously slowed or stopped (a state called respiratory depression), the body does not take in enough oxygen, and this lack of oxygen is asphyxia. So barbiturate-related asphyxia is essentially the oxygen deprivation that results when barbiturates depress breathing to a dangerous degree, which can lead to brain damage from lack of oxygen and to death. This is the main way that barbiturate overdose causes death, and it is a central reason why barbiturates are so dangerous.
This article explains what barbiturate-related asphyxia is, how barbiturates suppress breathing, why overdose is so dangerous, and how to get help. The central message is that barbiturates can dangerously slow or stop breathing, causing asphyxia (lack of oxygen), which can be fatal, that this danger is heightened by barbiturates’ narrow margin of safety and dramatically increased when they are combined with other depressants such as alcohol or opioids, and that barbiturate overdose is a life-threatening medical emergency. It is also important to understand that, because of these dangers and because barbiturate withdrawal can itself be dangerous, anyone dependent on barbiturates should seek medically supervised treatment rather than stopping suddenly. Understanding the danger of barbiturate-related asphyxia underlines why these drugs must be treated with great caution, and it is important to know that if a person is misusing or dependent on barbiturates, help is available and addiction is treatable.
How barbiturates suppress breathing
Barbiturates suppress breathing because of how they act on the central nervous system. Breathing is controlled by centres in the brain (in the brainstem) that regulate the drive to breathe. Barbiturates depress the central nervous system by enhancing the effect of a calming brain chemical (GABA), slowing down brain activity. In doing so, at high enough doses, they suppress the brain’s control of breathing, reducing the drive to breathe, so that breathing becomes slow, shallow, and inadequate, and, in severe cases, stops altogether. This is respiratory depression. When breathing is suppressed to this degree, the body cannot take in enough oxygen or remove enough carbon dioxide, leading to a dangerous lack of oxygen (asphyxia), which, if not reversed, causes damage to the brain and other organs and, ultimately, death.
A crucial factor that makes this especially dangerous with barbiturates is their narrow margin of safety, also called a narrow therapeutic index: the difference between a dose that produces the desired sedative effect and a dose that dangerously suppresses breathing is small. This means that taking somewhat too much, whether accidentally, to enhance the effect, or because tolerance has developed, can push a person from sedation into life-threatening respiratory depression. A further, and very important, danger is the effect of combining barbiturates with other central nervous system depressants. Alcohol, opioids, benzodiazepines, and other sedatives also depress the central nervous system and breathing, and when combined with barbiturates, their effects add together and can suppress breathing far more than either alone, dramatically increasing the risk of fatal respiratory depression and asphyxia. Many barbiturate-related deaths involve such combinations, particularly with alcohol. Additionally, a person deeply sedated by barbiturates may be unable to protect their airway, creating a further risk of asphyxia from the airway becoming blocked or from choking, for example if they vomit while unconscious and inhale it. So barbiturates suppress breathing through their action on the brain, and this danger is magnified by their narrow safety margin, by combination with other depressants, and by the loss of airway protection when deeply sedated.
| Aspect | Detail |
|---|---|
| What it is | Lack of oxygen from barbiturates suppressing breathing |
| Mechanism | Barbiturates depress the brain’s control of breathing |
| Result | Respiratory depression; asphyxia; brain damage; death |
| Narrow safety margin | Small gap between effective and fatal dose |
| Combinations | Alcohol/opioids/benzos greatly increase the danger |
| Airway risk | Deeply sedated person may choke or block their airway |
Why barbiturate overdose is so dangerous
Barbiturate overdose is a life-threatening medical emergency, and barbiturate-related asphyxia is the central reason why. In an overdose, the barbiturate suppresses breathing dangerously, causing the respiratory depression and asphyxia described, which can lead to loss of consciousness, coma, brain damage from lack of oxygen, and death. Signs of a barbiturate overdose can include extreme drowsiness or unresponsiveness, confusion, slurred speech, poor coordination, slow, shallow, or difficult breathing, a weak or slow pulse, low body temperature, and, as it progresses, unconsciousness and coma. Because the dangerous effect is on breathing, the situation can deteriorate to a fatal outcome if not treated urgently. Importantly, there is no simple antidote that reverses barbiturate overdose in the way naloxone reverses opioid overdose, so treatment relies on supportive intensive medical care, including support for breathing (such as assisted ventilation) and other measures, which is why urgent hospital care is essential.
The danger of barbiturate overdose, and therefore of barbiturate-related asphyxia, is greatly increased in several situations: when barbiturates are combined with alcohol, opioids, or other depressants (a very common factor in deaths); when higher doses are taken, whether through misuse, an attempt to enhance the effect, or because tolerance has led to escalating use (dangerously, tolerance to the desired effects develops faster than tolerance to the dose that suppresses breathing, so as a person takes more to get the same effect, they move closer to a fatal, breathing-suppressing dose); and in deliberate overdose. Because of all this, barbiturates are considered among the more dangerous drugs, which is part of why they have largely been replaced by safer medicines for many uses. If a barbiturate overdose is suspected, with signs such as very slow or difficult breathing, unresponsiveness, or coma, it is a medical emergency requiring immediate help. Barbiturate-related asphyxia is the deadly core of this danger, and understanding it underlines why barbiturates must be used with extreme caution, only as prescribed, never combined with alcohol or other depressants, and never misused.
Getting help
Given the serious dangers of barbiturates, including the risk of fatal asphyxia, it is important that anyone misusing or dependent on barbiturates seeks help, and that any suspected overdose is treated as an emergency. In an overdose situation, if someone shows signs such as very slow, shallow, or difficult breathing, extreme drowsiness or unresponsiveness, or coma, especially if barbiturates may have been combined with alcohol or other drugs, call your local emergency number immediately, as urgent medical care is needed to support breathing and prevent death. While waiting for help, if the person is unconscious but breathing, placing them on their side (the recovery position) can help protect their airway and reduce the risk of choking. Beyond the emergency, barbiturate dependence and addiction need proper treatment, and, importantly, this must be done carefully, because stopping barbiturates suddenly after regular use can itself cause a dangerous, potentially life-threatening withdrawal (including seizures), so withdrawal must be medically supervised.
Treatment for barbiturate dependence and addiction begins with a medically supervised withdrawal (detox), in which the drug is reduced gradually under medical monitoring to keep the person safe, and continues with counselling and behavioural therapies to address the patterns and underlying issues driving use, support for recovery, and treatment of any co-occurring conditions. Depending on the severity, this is often best done in a setting where the person can be closely monitored, given the medical risks. The reassuring message is that, with safe, medically supervised treatment and support, people can overcome barbiturate dependence and addiction and recover. The key messages are that barbiturate-related asphyxia is a lack of oxygen caused by barbiturates suppressing breathing, that this respiratory depression is the main way barbiturate overdose kills and is a life-threatening emergency, that the danger is heightened by barbiturates’ narrow safety margin and by combining them with alcohol or other depressants, and that anyone dependent on barbiturates should seek medically supervised treatment rather than stopping suddenly. If you or someone you know is misusing or dependent on barbiturates, it is important to seek help, as these drugs are genuinely dangerous, but addiction is treatable and recovery is possible with the right, safely managed support.
Summary
Barbiturate-related asphyxia refers to a lack of oxygen (asphyxia) caused by barbiturates suppressing a person’s breathing. Barbiturates are a class of sedative drugs that depress the central nervous system, and in high doses or overdose they can dangerously slow or stop breathing (respiratory depression), so that the body does not get enough oxygen; this can lead to asphyxia, brain damage from lack of oxygen, and death, and it is the main way barbiturate overdose kills. This danger is heightened by the fact that barbiturates have a narrow margin of safety (the difference between an effective and a fatal dose is small), and it is dramatically increased when barbiturates are combined with other central nervous system depressants such as alcohol or opioids, which also suppress breathing. Deeply sedated by barbiturates, a person may also be at risk of asphyxia from their airway becoming blocked or from choking, for example on vomit, because they cannot protect their airway. Barbiturate overdose is a life-threatening medical emergency. Because of these dangers, anyone dependent on barbiturates should never stop suddenly (withdrawal can also be dangerous) and should seek medically supervised treatment. If you or someone you know is misusing or dependent on barbiturates, help is available, and addiction is treatable.
As Dr. Ponlawat Pitsuwan, addiction medicine specialist at Phuket Island Rehab, puts it, “Barbiturate-related asphyxia is a clinical way of describing something very simple and very frightening: the drug switches off the brain’s drive to breathe, and the person suffocates from the inside. What makes barbiturates so lethal is how little room for error there is, the gap between the dose that sedates and the dose that stops your breathing is narrow, and it closes completely the moment you add alcohol or an opioid. And unlike an opioid overdose, there is no naloxone to reverse it; all we can do is support breathing in intensive care. That is why these drugs frighten me, and why, if someone is dependent, coming off them must be done medically, never cold turkey. The good news is that, done safely, recovery is entirely possible.”
Frequently asked questions
What is barbiturate-related asphyxia?
Barbiturate-related asphyxia is asphyxia, a dangerous lack of oxygen reaching the body’s tissues, caused by barbiturates suppressing a person’s breathing. Barbiturates are sedative drugs that depress the central nervous system, and among the functions the central nervous system controls is breathing. In high doses or overdose, barbiturates can suppress the brain’s control of breathing, so that breathing becomes dangerously slow, shallow, or stops altogether (respiratory depression). When breathing is suppressed to this degree, the body cannot take in enough oxygen, and this lack of oxygen is asphyxia, which can lead to brain damage from oxygen deprivation and to death. Barbiturate-related asphyxia is the main way barbiturate overdose causes death. A deeply sedated person may also be at risk of asphyxia from their airway becoming blocked or from choking (for example on vomit) because they cannot protect their airway. This danger is heightened by barbiturates’ narrow margin of safety and dramatically increased when they are combined with other depressants like alcohol or opioids. So barbiturate-related asphyxia is essentially the deadly oxygen deprivation that results when barbiturates depress breathing, and it is the central danger of barbiturate overdose, which is a life-threatening medical emergency.
How do barbiturates cause death?
Barbiturates most commonly cause death through respiratory depression leading to asphyxia, that is, by suppressing breathing so that the body does not get enough oxygen. Barbiturates depress the central nervous system, including the brain’s control of breathing, and in high doses or overdose they can slow or stop breathing, causing a dangerous lack of oxygen (asphyxia) that leads to loss of consciousness, coma, brain damage, and death if not reversed. This is the central mechanism of fatal barbiturate overdose. Several factors increase the danger: barbiturates have a narrow margin of safety, so the difference between an effective and a fatal dose is small; tolerance to the desired effects develops faster than tolerance to the breathing-suppressing effects, so escalating use moves a person closer to a fatal dose; and, very importantly, combining barbiturates with other central nervous system depressants, such as alcohol or opioids, greatly increases the suppression of breathing and the risk of death. A deeply sedated person may also die from their airway becoming blocked or from choking. Unlike opioid overdose, there is no simple antidote to reverse barbiturate overdose, so it relies on urgent supportive medical care, including support for breathing. This is why barbiturate overdose is a life-threatening emergency and why barbiturates are considered among the more dangerous drugs.
Why is combining barbiturates with alcohol or opioids so dangerous?
Combining barbiturates with alcohol, opioids, or other central nervous system depressants is extremely dangerous because these substances all depress the central nervous system and, crucially, suppress breathing, so together their effects add up and can suppress breathing far more than any of them alone. Barbiturates already carry a serious risk of respiratory depression (dangerously slowed or stopped breathing) and asphyxia in overdose, with a narrow margin of safety. When alcohol (which is also a central nervous system depressant), opioids (which suppress breathing), or benzodiazepines and other sedatives are added, the combined depressant effect on breathing can be much greater, dramatically increasing the risk of fatal respiratory depression and asphyxia, even at doses of each that might not be fatal alone. This is why many barbiturate-related deaths involve such combinations, particularly with alcohol. The combination can rapidly and unpredictably suppress breathing to a deadly degree. For this reason, barbiturates must never be combined with alcohol, opioids, or other sedatives without explicit medical guidance, and doing so is one of the most dangerous things a person can do with these drugs. This danger of combinations is a key reason for the risk of barbiturate-related asphyxia and death, and it applies to sedatives more generally. Anyone taking barbiturates should avoid alcohol and other depressants, and any suspected overdose involving such combinations should be treated as an urgent emergency.
What are the signs of a barbiturate overdose?
The signs of a barbiturate overdose reflect the drug’s dangerous depression of the central nervous system and breathing. They can include extreme drowsiness or unresponsiveness, confusion, slurred speech, poor coordination and unsteadiness, and, critically, slow, shallow, or difficult breathing (respiratory depression), which is the most dangerous feature. Other signs can include a weak or slow pulse, low blood pressure, low body temperature, and, as the overdose progresses, loss of consciousness and coma. Because the central danger is the suppression of breathing leading to asphyxia (lack of oxygen), the most worrying signs are those indicating that a person is deeply sedated, cannot be roused, or is breathing slowly, shallowly, or not at all. A barbiturate overdose is a life-threatening medical emergency, and the danger is greatly increased if barbiturates have been combined with alcohol or other depressants. If you suspect a barbiturate overdose, with these signs, call your local emergency number immediately; if the person is unconscious but breathing, place them on their side to help protect their airway. Unlike opioid overdose, there is no simple antidote, so urgent medical care to support breathing is essential. Recognising these signs and acting quickly can be life-saving. Any suspected barbiturate overdose should always be treated as an emergency requiring immediate professional help.
Is there an antidote for barbiturate overdose?
No, there is no simple, specific antidote that reverses barbiturate overdose in the way that naloxone reverses opioid overdose. This is an important and dangerous difference between barbiturates and opioids. For an opioid overdose, naloxone can rapidly reverse the effects, including the suppression of breathing, if given in time. For a barbiturate overdose, there is no equivalent reversal agent, so treatment relies on supportive intensive medical care in hospital. This supportive care can include supporting or taking over the person’s breathing (such as with assisted ventilation or a breathing machine), maintaining blood pressure and other vital functions, and other measures to keep the person alive and stable while the drug is cleared from their body, along with specific treatments in some cases. Because there is no quick antidote, barbiturate overdose is particularly dangerous and depends on getting the person urgent hospital care as quickly as possible, so that their breathing and other functions can be supported through the overdose. This lack of an antidote is one reason barbiturate overdose is so serious and why these drugs are considered among the more dangerous. It underlines the importance of preventing overdose in the first place, by using barbiturates only as prescribed, never combining them with alcohol or other depressants, and never misusing them, and of treating any suspected overdose as an immediate emergency requiring professional medical care.
How is barbiturate dependence treated safely?
Barbiturate dependence must be treated carefully and under medical supervision, because both barbiturate overdose and barbiturate withdrawal are dangerous. Treatment begins with a medically supervised withdrawal (detox), which is essential because stopping barbiturates suddenly after regular use can cause a severe, potentially life-threatening withdrawal syndrome, including seizures. During detox, the drug is reduced gradually under close medical monitoring, sometimes by switching to a longer-acting barbiturate and tapering it slowly, or using other supportive measures, to keep the person safe and manage withdrawal symptoms; for significant dependence, this is often best done in a setting where the person can be closely observed, given the medical risks. Once safe withdrawal is achieved, lasting recovery involves counselling and behavioural therapies to help the person understand and change the patterns driving their use, manage cravings, and address any underlying issues, along with support for recovery and treatment of any co-occurring mental health conditions, such as anxiety, depression, or insomnia, which may have led to the barbiturate use. Depending on severity, treatment may be provided through a structured program, sometimes residential. With this combination of safe, medically supervised withdrawal, therapy, and support, people can overcome barbiturate dependence and addiction and recover. Because of the serious dangers involved, both of overdose and of unsupervised withdrawal, it is essential that anyone dependent on barbiturates seeks professional, medically supervised help rather than trying to stop on their own. If you or someone you know is dependent on barbiturates, seeking this help is important, and recovery is possible.
Sources
National Library of Medicine (MedlinePlus). Barbiturate Intoxication and Overdose. https://medlineplus.gov/ency/article/000951.htm
Drug Enforcement Administration (DEA). Barbiturates Drug Fact Sheet. https://www.dea.gov/factsheets/barbiturates
National Institute on Drug Abuse (NIDA). Prescription CNS Depressants. https://nida.nih.gov/research-topics/prescription-drugs
National Library of Medicine (StatPearls). Barbiturate Toxicity. https://www.ncbi.nlm.nih.gov/books/
Substance Abuse and Mental Health Services Administration (SAMHSA). Substance Use. https://www.samhsa.gov/
World Health Organization (WHO). Sedative Overdose and Poisoning. https://www.who.int/
Barbiturate-related asphyxia — key entities and related terms
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