Benzodiazepine Overdose: Side Effects and Dosage

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Are you taking a benzodiazepine but would like to take more than prescribed? Do you think you might be addicted to benzodiazepines? Are you worried about a loved one that may be abusing a benzodiazepine? Are you concerned that you or someone you love is experiencing an overdose? Whatever your current situation may be, it is important to access help. Here we explore the adverse effects of benzodiazepines, what a benzodiazepine overdose looks like, and how to get the care needed to recover from benzodiazepine abuse and/or overdose. 


Benzodiazepines are a class of prescription drugs that can treat a range of conditions. Benzodiazepines alter the activity of brain chemicals that trigger stress. As such, this type of drug is often prescribed for insomnia, generalised anxiety disorder, seizures, and panic disorder. The short-term use of such medications is usually safe and effective. However, due to abuse potential, long-term use of benzodiazepines can lead to addiction, and a potentially fatal overdose, particularly when taken with other depressant substances. The number of benzodiazepine-related deaths in Europe is on the rise but with the right care, fatalities can be avoided. 

Signs, Risks & Symptoms of a Benzodiazepine Overdose

Benzodiazepine overdose occurs when one of the drugs in the benzodiazepine class is ingested in greater quantities than recommended. Deaths from single-drug benzodiazepine overdoses occur infrequently, however, high doses of benzodiazepines combined with alcohol, barbiturates, opioids or some antidepressants can lead to severe complications, even death. A benzodiazepine overdose needs to be handled medically to avoid the serious symptoms of benzodiazepine withdrawal syndrome. 

Benzodiazepine withdrawal syndrome is a group of symptoms caused when someone who has been taking benzodiazepines develops a physical dependence and then reduces the dose or stops taking them without tapering slowly. 

The symptoms of benzodiazepine withdrawal include:

  • anxiety and panic attacks
  • burning sensations and pain in the upper spine
  • confusion and cognitive difficult
  • difficulty with concentration
  • dry retching and nausea
  • hand tremors and shaking
  • headache
  • increased tension
  • irritability
  • memory loss
  • muscular stiffness and/or pain
  • palpitations
  • sleep problems
  • sweating
  • weight loss and appetite changes

Rapid Discontinuation May Result in More Serious Symptoms Such As:

  • catatonia – impaired movement
  • confusion
  • convulsions
  • coma
  • delirium tremens
  • hyperthermia
  • mania

When managing benzodiazepine withdrawal, it is better to reduce too slowly rather than too quickly. The rate of dosage reduction sould be overseen by a doctor to minimise the intensity and severity of symptoms to prevent serious health issues. 

What Happens in a Benzodiazepine Overdose?

If you are misusing or abusing sedatives such as benzodiazepines, this can cause significant harm to your health and may lead to an overdose. A benzodiazepine overdose may be intentional, as part of recreational misuse, or accidental. Knowing the signs of a sedative overdose will allow you to quickly facilitate getting medical support for yourself or someone else.

The key feature of a benzodiazepine overdose is excessive sedation, but the signs and symptoms may differ from person to person depending on a variety of factors such as dosage, frequency of use, medical history, physicality, and age. 

Key signs that someone has overdosed on a benzodiazepine are trouble breathing, blueish fingernails and lips, confusion and disorientation, dizziness, blurred vision, slurred speech, muscle weakness, lack of coordination, vomiting, altered mental state, stupor and even coma. Someone may have more serious complications following an overdose such as pneumonia, muscle damage, brain damage, and death, as a result of respiratory problems, lack of oxygen, or physical trauma caused by a loss of consciousness and/or immobility on a hard surface.

If You Think You’re Having (Or Witnessing) a Benzodiazepine Overdose

If you think you have overdosed on benzodiazepines or are witnessing someone who may have overdosed it is important to call 999 immediately to access emergency help. Be prepared to provide your location and the amount and types of substance(s) ingested if known. If you are a loved one, remain with the individual who has overdosed and keep their airway open. The sooner you or your loved one has been treated the less chance there is of the overdose proving fatal.  

How Are Benzodiazepine Overdoses Typically Treated?

Overdose victims will be transported to the hospital where they may be treated with respiratory support, intravenous fluids, and/or medications to reverse the effects of a benzodiazepine overdose.
In some instances of a benzodiazepine overdose, the emergency care team may administer flumazenil, a benzodiazepine antidote medication, to reverse the effects of the overdose. Flumazenil is short-acting and may not completely resolve depressed breathing, so may need to be given every 20 minutes. 

Many benzodiazepine overdoses involve opioids. If an individual has taken another substance besides benzodiazepines or has taken a counterfeit sedative that could have been cut with a toxic dose of opioids, Narcan (naloxone) may be administered. Narcan can be given to reverse an opioid overdose. Narcan won’t do anything to reverse an overdose from benzodiazepines, but if someone has used opioids with a benzodiazepine, or a benzodiazepine cut with opioids, it could save their life.

Mixing Benzodiazepine With Other Drugs

Taking benzodiazepines in combination with other central nervous system depressants—prescription opioids, heroin, alcohol, or other benzodiazepines—is dangerous and increases the risk of a life-threatening overdose. Many who abuse benzodiazepines will develop a tolerance after which the effect of the drug is reduced. As such, if they don’t receive help, many will look to a combination of drugs to experience the same desired effect and avoid withdrawal. 

Benzo and Alcohol

The most common substance abused with benzodiazepines is alcohol. This might be inadvertent if someone is taking a benzodiazepine as prescribed. Alcohol and benzodiazepines both affect chemicals in the brain that slow the activity of the nervous system causing a sedative effect. Mixing these two depressants can reduce cognition leading to risk-taking behaviours, and oversedate sometimes causing death. Side effects of combining alcohol and benzodiazepines are nausea, fainting, slurred speech, anxiety, seizures, digestive disturbances, heart attack, and liver damage. 

Benzodiazepines and Other Prescription Medications

If tolerance for one benzodiazepine has developed, someone may start using two benzodiazepines to achieve the desired sedative effect. Taking two benzodiazepines concurrently increases the risk of dangerous side effects such as organ damage, breathing difficulties, confusion, drowsiness, low blood pressure, sleep problems, and depression.

Benzodiazepines and Opioids

A common cause of benzodiazepine overdose is when sedatives are mixed with prescription (methadone, oxycodone, hydrocodone) or illicit (heroin) opioids. The co-abuse of benzodiazepine and opioids is substantial and has negative consequences for general health and overdose lethality. Researchers have found benzodiazepines in the illicit opioid supply in some areas which may mean that people are taking benzodiazepines in combination with illicit opioids knowingly or unknowingly. The combined use of these drug types increases the risk for potentially lethal respiratory depression.

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Benzodiazepine Overdose Statistics

A 2022 report from The Office of National Statistics on drug poisoning shows a significant increase in deaths involving new psychoactive substances (NPS) in 2021. This rise was driven by an increase in the number of deaths involving benzodiazepine. There have been increasing numbers of deaths involving benzodiazepines — a rise of 13% when compared with 2020, from 476 to 538 deaths.

The report also shows that across Europe, rates of deaths involving heroin or morphine have been increasing despite the number of new heroin and morphine users having fallen. This indicates higher rates of death among existing long-term drug users one possible cause of which is a new trend in taking benzodiazepines alongside heroin or morphine, which increases the risk of overdose.

Benzodiazepine Abuse & Addiction

Sedatives are widely prescribed for a variety of conditions and are relatively safe when used short-term, intermittently, or ‘as needed’. However, sedatives are generally controlled substances with abuse potential. As such, if used long-term or in large doses, sedatives can be habit-forming.

Sedatives act on the body’s central nervous system (CNS), depressing it by binding to certain receptors and activating inhibitory neurohormones. As a result, brain activity slows down, and the wanted effects of relaxation and euphoria are experienced. However, long-term misuse leads to significant health concerns.

Sedative addiction is a serious condition that occurs when the rewarding effects of a drug alter the brain’s limbic system, causing intense cravings and impulses to use the drug again despite consequences to health, relationships, and everyday life.

If you have been using sedatives for too long or in high doses, you might start to develop a tolerance, meaning you need more and more of the drug to achieve the same result. At this point, when your brain has become used to sedatives, you may feel as if you need the drug to maintain normalcy or to avoid uncomfortable symptoms. 

benzodiazepine overdose

If you are concerned about yourself or someone else, there are some visible signs of sedative addiction to look out for. These include altered sleep patterns, intoxication similar to being drunk, loss of coordination, hiding drugs, lying about sedative use or frequency of use, and mixing sedatives with other mood-altering substances.

Adverse effects of sedative use that you may experience include sedation, drowsiness, poor memory, and the risk of motor vehicle accidents rising dramatically, particularly when taken with alcohol. If you are taking sedatives, it is important to note that longer-term use of sedatives can cause depression, dementia, worsening anxiety, and chemical dependence leading to withdrawal syndromes and potential overdose which can be fatal. Cancer, pneumonia, and other infections are also a risk. 

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Is benzodiazepine overdose lethal?

Benzodiazepine overdose occurs when excessive amounts of benzodiazepine medications are taken. Acute overdose may induce respiratory depression resulting in coma and even death. Cardiac-related effects and fatalities are rare in pure benzodiazepine toxicities but the risk increases when combined with opioids.  

What does benzodiazepine toxicity look like?

Whether accidental or planned, benzodiazepine toxicity will primarily present with central nervous system depression ranging from mild drowsiness to a coma-like, stuporous state. Someone experiencing benzodiazepine toxicity may appear incredibly sleepy or drunk, they may have even lose consciousnesses. 

Can benzodiazepines be fatal?

Cardiac-related effects and fatalities are rare in pure benzodiazepine toxicities; however, they do happen depending on the amount taken and how quickly emergency support is received. Fatalities are more common when benzodiazepines are mixed with other depressant drugs.

How do you reverse a benzodiazepine overdose?

While the main treatment of a benzodiazepine overdose is emergency medical care, there is an “antidote” that may be used in limited situations. Flumazenil is a medicine that can reverse benzodiazepine-induced sedation, but it is not recommended for routine reversal. Seizures and cardiac issues can occur after flumazenil has been administered which can cause fatalities. Flumazenil can also precipitate acute withdrawal syndromes in those with chronic benzodiazepine dependence, which can be life-threatening. 

benzodiazepine overdose


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