Klonopin Overdose: Signs, Risks & Treatment

A Klonopin overdose can be a medical emergency, especially when the medication is mixed with alcohol, opioids, sleep medications, or other central nervous system depressants. Klonopin, the brand name for clonazepam, is a benzodiazepine used to treat seizure disorders and panic disorder (U.S. Food and Drug Administration, 2021). Taking too much can cause extreme sedation, confusion, poor coordination, slowed breathing, loss of consciousness, coma, and in severe cases, can lead to death. FDA prescribing information warns that benzodiazepines used with opioids can cause profound sedation, respiratory depression, coma, and death (U.S. Food and Drug Administration, 2021).

Call 911 immediately if someone has slow or difficult breathing, cannot stay awake, is severely confused, has blue or gray lips, loses consciousness, or cannot be woken up after taking this medication. If the person is awake and stable but may have taken too much, call Poison Control at 1-800-222-1222 for immediate guidance.

Key Takeaways

• Call 911 if someone has slow breathing, blue or gray lips, severe confusion, repeated vomiting, loss of consciousness, or cannot be woken up after taking clonazepam.
• Klonopin overdose can cause extreme drowsiness, slurred speech, poor coordination, slowed breathing, low blood pressure, coma, and death (Kang et al., 2023).
• There is no single lethal dose. The danger depends on amount taken, tolerance, age, liver function, breathing health, alcohol or opioid use, and how quickly emergency care is received.
• Combining this medication with opioids is especially dangerous. FDA labeling warns the combination can cause profound sedation, breathing failure, coma, and death (U.S. Food and Drug Administration, 2021).
• In CDC data from January–June 2020, 92.7% of benzodiazepine-involved overdose deaths also involved opioids (Liu et al., 2021).
• Naloxone can reverse opioid poisoning but not clonazepam. Give naloxone if opioids may be involved, but still call 911 (Centers for Disease Control and Prevention, 2024).
• Flumazenil can reverse sedative effects in select cases, but it can trigger seizures or withdrawal in people with dependence, seizure disorders, or mixed-drug poisoning (Shoar et al., 2024).
• Withdrawal can be dangerous. The 2025 tapering guideline says dependent patients should not stop abruptly because withdrawal can include seizures or delirium (Brunner et al., 2025).

Emergency Medical Steps if Someone Took Too Much

If someone took too much Klonopin, do not wait for their condition to worsen. The safest response depends on the amount taken, whether alcohol or another drug was involved, how awake the person is, and whether breathing has changed.

Call 911 immediately if the person has:

• Slow, shallow, or difficult breathing
• Blue, gray, or pale lips or skin
• Loss of consciousness
• Cannot be woken up
• Severe confusion
• Extreme drowsiness
• Repeated vomiting
• Very slow heart rate
• Weak pulse
• Seizures
• Symptoms that feel life-threatening

Call Poison Control at 1-800-222-1222 if the person is awake and stable but may have taken too much. Have the medication bottle available if possible. The dose, time taken, other medications, alcohol or drug use, and current symptoms will help professionals decide what to do next.

Do not give alcohol, opioids, sleep medications, sedatives, or extra pills. Do not let the person drive. If they are unconscious or vomiting, place them on their side to reduce choking risk and stay with them until help arrives.

If opioids may be involved, give naloxone if it is available. Naloxone can reverse the opioid part of an emergency, but it does not reverse clonazepam. A person may still need breathing support, monitoring, or other emergency care after naloxone is given (Centers for Disease Control and Prevention, 2024).

Can You Overdose on Clonazepam?

Yes. A clonazepam overdose can happen when someone takes more than prescribed, takes doses too close together, uses the medication without a prescription, or combines it with alcohol, opioids, sleep medications, or other sedatives.

This may be accidental or intentional. Someone may forget they already took a pill, misunderstand instructions, take another person’s prescription, or mix the drug with alcohol or opioids without realizing how dangerous the combination can be.

Klonopin can stay in the body for a long time. Its long duration means sedation and impairment may continue after the person first feels sleepy. This can make it harder to tell whether symptoms are improving or getting worse without medical guidance. FDA labeling describes clonazepam as a long-acting benzodiazepine and provides elimination half-life information that helps explain why effects may persist (U.S. Food and Drug Administration, 2021).

Signs and Symptoms

Klonopin overdose symptoms can affect alertness, coordination, breathing, blood pressure, heart rate, and consciousness. Symptoms may look like heavy sleepiness at first, but they can become dangerous if breathing slows or the person cannot wake up. Benzodiazepine toxicity commonly presents with central nervous system depression, impaired coordination, slurred speech, and altered mental status; severe cases may involve breathing problems, especially when other depressants are involved (Kang et al., 2023).

Possible signs include:

• Extreme drowsiness
• Confusion
• Slurred speech
• Poor coordination
• Stumbling or falling
• Dizziness
• Blurred vision
• Weakness
• Slow reflexes
• Mood changes
• Agitation or unusual behavior
• Slow or shallow breathing
• Low blood pressure
• Slow heart rate
• Vomiting
• Loss of consciousness
• Coma

A person does not need to have every warning sign to be in danger. Slow breathing, inability to wake up, blue or gray lips, severe confusion, or loss of consciousness should always be treated as an emergency.

How Much Is Too Much?

There is no exact amount that applies to everyone. A dose that causes severe sedation in one person may affect another person differently depending on tolerance, age, body size, liver function, medical conditions, and other substances involved.

Danger may be higher if someone:

• Takes more than prescribed
• Takes repeated doses in a short period
• Uses Klonopin without a prescription
• Mixes it with alcohol
• Combines it with opioids
• Uses other benzodiazepines or sleep medications
• Has sleep apnea, COPD, asthma, or another breathing condition
• Has liver disease
• Is older or medically fragile
• Has low tolerance to sedatives
• Uses it to get high or intensify another substance

Do not use online dose estimates to decide whether someone is safe. If the amount taken may be unsafe, call Poison Control or 911.

Is There a Lethal Dose?

There is no single lethal amount that applies to everyone. Fatal risk depends on the amount taken, whether other substances were involved, tolerance, age, liver function, breathing health, and how quickly emergency care is received.

Clonazepam alone is less likely to cause fatal poisoning than clonazepam mixed with other depressants. The danger rises sharply when it is combined with alcohol, opioids, sleep medications, muscle relaxers, or other sedatives because these substances can add to each other’s effects on breathing and consciousness. A CDC analysis found that 92.7% of benzodiazepine-involved overdose deaths during January–June 2020 also involved opioids, showing how often fatal cases involve other substances (Liu et al., 2021).

A specific number should not be used to decide whether someone is safe. If a person took more than prescribed, is extremely sleepy, cannot wake up, or may have mixed this medication with alcohol or opioids, treat it as urgent.

Alcohol, Opioids, and Sedative Danger

Klonopin is especially dangerous when mixed with alcohol, opioids, or other depressants. These substances all slow central nervous system activity. When combined, they can cause stronger sedation than expected and may slow breathing to a dangerous level.

This applies to prescription opioids, illicit opioids, alcohol, sleeping pills, muscle relaxers, other sedatives, and some mental health medications. FDA labeling warns that Klonopin and opioids can cause profound sedation, breathing failure, coma, and death when used together (U.S. Food and Drug Administration, 2021). Research also shows that benzodiazepine and alcohol co-involvement in opioid-involved fatalities is common and varies by opioid subtype (Tori et al., 2020).

If someone took this medication with alcohol or opioids and is very sleepy, breathing slowly, vomiting, confused, or difficult to wake up, call 911. Do not assume the person can safely “sleep it off.”

Mixed-Drug Emergencies and Polysubstance Use

Many serious sedative-related emergencies involve more than one substance. This is called polysubstance use, and it can happen intentionally or accidentally.

A person may mix this medication with alcohol to intensify sedation, with opioids to increase euphoria, or with stimulants to “come down.” These combinations are dangerous because one substance can mask or intensify the effects of another. A review of polysubstance trends describes the current crisis as heavily involving multiple substances rather than one drug alone (Peppin et al., 2020).

Mixed-drug emergencies can be harder to recognize and treat because symptoms may not follow one clear pattern. For example, opioids may cause pinpoint pupils and severe breathing problems, while alcohol may worsen sedation, vomiting, and choking risk. Emergency responders need to know everything the person may have taken so they can choose the safest treatment.

What Is Klonopin?

Klonopin is the brand name for clonazepam. It belongs to a class of medications called benzodiazepines, often called “benzos.” These medications slow activity in the central nervous system and can reduce seizures, panic symptoms, anxiety, and muscle tension. Klonopin is FDA-approved for certain seizure disorders and panic disorder (U.S. Food and Drug Administration, 2021).

Because this medication slows brain and nervous system activity, it can also cause sedation, dizziness, confusion, impaired coordination, and memory problems. These effects become more dangerous when it is taken in high amounts or mixed with alcohol, opioids, or other sedating substances.

It should only be taken as prescribed. Taking someone else’s prescription, taking extra pills, or using it to get high can increase the chance of poisoning, dependence, withdrawal, and addiction.

Dosage and Why Dose Alone Does Not Predict Danger

Klonopin dosage depends on the condition being treated, the person’s medical history, and the prescriber’s instructions. Amounts used for panic disorder are often different from those used for seizure disorders.

A dose should never be changed without a prescriber’s guidance. Even prescribed use can become unsafe if the medication is mixed with alcohol, opioids, sedatives, or other substances that slow breathing and alertness.

The safest amount is the amount prescribed specifically for that person. Taking extra pills, using it more often than directed, or combining it with other depressants can create danger even when the amount does not seem high.

Risk Factors

Certain factors can make a serious sedative reaction more likely or more dangerous. These include medical conditions, age, tolerance, and substance use.

Factors include:

• High-dose use
• More frequent use than prescribed
• Mixing with alcohol
• Mixing with opioids
• Using multiple sedatives
• Low tolerance
• Older age
• Sleep apnea
• COPD or other lung disease
• Liver disease
• History of substance use disorder
• Use without a prescription
• Taking Klonopin to get high
• Recent relapse after a period without use

People with breathing conditions, liver problems, or polysubstance use may need closer monitoring after taking clonazepam.

What Happens During Severe Sedation?

During a serious sedative reaction, the central nervous system slows down too much. The person may become very sleepy, confused, uncoordinated, or unable to respond normally.

The most serious concern is slowed or shallow breathing. Without enough oxygen, severe cases can lead to brain injury, coma, or death if not treated quickly. This is especially important when clonazepam is combined with opioids or alcohol because those substances can further slow breathing and consciousness (U.S. Food and Drug Administration, 2021; Tori et al., 2020).

Medical teams may monitor breathing, oxygen levels, heart rhythm, blood pressure, and level of consciousness. Treatment focuses on keeping the person stable until the drug’s effects wear off.

Emergency Treatment

Klonopin overdose treatment is based on the person’s condition. There is no safe home remedy that can reliably reverse a serious benzodiazepine overdose.

Emergency treatment may include:

• Airway support
• Oxygen or breathing support
• Monitoring heart rate, breathing, and blood pressure
• IV fluids
• Treatment for vomiting or aspiration risk
• Cardiac monitoring when needed
• Observation until sedation improves
• Screening for alcohol, opioids, or other substances
• Mental health evaluation if the event may have been intentional

Treatment for benzodiazepine toxicity is usually supportive and focuses on airway protection, breathing, and monitoring until sedation improves (Kang et al., 2023). Flumazenil may be considered in select cases, but it is not used for everyone. It can cause seizures or withdrawal in people who are dependent, have seizure disorders, or have mixed-substance poisoning. Medical professionals decide whether the benefits outweigh the risks.

Why Flumazenil Is Not Always Used

Flumazenil is sometimes described as a reversal medication, but that does not mean it is always the safest option. In many sedative poisonings, supportive care is the main treatment.

Flumazenil can rapidly reverse sedation in some cases, but it can also trigger seizures or severe withdrawal in people who regularly use benzodiazepines. It can also be risky in mixed-drug emergencies, especially when other substances may increase seizure or heart rhythm danger. StatPearls notes that flumazenil can precipitate withdrawal in people with chronic dependence and may lower the seizure threshold, potentially causing life-threatening seizures (Kang et al., 2023; Shoar et al., 2024).

Because of these concerns, flumazenil should only be given by medical professionals in carefully selected situations.

Long-Term Effects After Severe Sedation

Many people recover after prompt care, but serious cases can have lasting effects, especially if breathing was slowed for too long or oxygen levels dropped.

Possible long-term effects may include:

• Memory problems
• Trouble concentrating
• Lingering fatigue
• Falls or injuries
• Aspiration pneumonia
• Muscle injury from prolonged immobility
• Brain injury from lack of oxygen
• Worsened anxiety or depression
• Increased chance of another emergency if use continues

A serious poisoning event can also be a warning sign that use has become unsafe. Follow-up treatment can help reduce the chance of another crisis.

Signs of Misuse or Abuse

Klonopin misuse means using it in a way other than prescribed. Some people misuse it to feel calm, sedated, detached, or euphoric. Others combine it with alcohol or opioids to intensify effects, which can quickly become dangerous.

Warning signs may include:

• Taking more than prescribed
• Running out early
• Taking it without a prescription
• Taking someone else’s pills
• Mixing it with alcohol or opioids
• Needing higher amounts for the same effect
• Feeling unable to function without it
• Blackouts, falls, or injuries
• Hiding use from family or providers
• Doctor shopping
• Cravings
• Failed attempts to stop

People who abuse Klonopin may be at higher risk for dependence, addiction, and another emergency involving sedation or breathing problems.

Dependence, Addiction, and Withdrawal

Dependence can develop when the body adapts to the medication. A person may feel unable to function without it, need higher amounts for the same effect, or experience withdrawal symptoms when they try to stop. The 2025 Joint Clinical Practice Guideline on Benzodiazepine Tapering notes that physical dependence can develop within weeks and that abrupt discontinuation should be avoided in patients likely to be dependent (Brunner et al., 2025).

Addiction may be present when someone keeps using despite harm, such as blackouts, injuries, relationship problems, running out early, or mixing it with other substances. Addiction can affect mood, memory, work, finances, relationships, and safety. It can also increase the chance of another emergency if the person continues using high amounts or combining substances.

Withdrawal Symptoms

Withdrawal can be serious, especially after long-term use, high-dose use, or sudden stopping. Symptoms may be uncomfortable and, in severe cases, may include seizures or delirium. The 2025 Joint Clinical Practice Guideline on Benzodiazepine Tapering states that withdrawal symptoms can range from anxiety and sleep problems to seizures and delirium, and that patients likely to be physically dependent should not stop abruptly (Brunner et al., 2025).

Possible withdrawal symptoms include:

• Anxiety
• Panic
• Insomnia
• Irritability
• Tremors
• Sweating
• Nausea
• Headache
• Muscle pain
• Sensory sensitivity
• Confusion
• Agitation
• Cravings
• Seizures in severe cases

People who take Klonopin regularly should not stop suddenly without medical guidance. A supervised taper may be needed to reduce withdrawal danger. The same guideline recommends gradual dose reductions under clinical supervision when tapering is appropriate (Brunner et al., 2025).

How To Prevent Taking Too Much

The safest way to reduce harm is to take the medication only as prescribed. Do not increase the amount, take extra pills, or mix it with alcohol, opioids, sleep medications, or sedatives unless your prescriber specifically says it is safe.

To lower the chance of a serious reaction:

• Take it only as directed
• Do not mix it with alcohol
• Do not combine it with opioids or sedatives unless directed
• Avoid taking someone else’s prescription
• Tell your prescriber about all medications and substances you use
• Store it securely away from others
• Ask your provider before changing the amount
• Seek help if you feel unable to control your use

If the medication no longer works as prescribed or you feel unable to stop, treatment support may be needed.

When to Call a Doctor Immediately

Treatment may be helpful when use has become difficult to control, unsafe, or connected to alcohol, opioid, or other drug use.

Call a doctor immediately or reach out for professional support if you or a loved one:

• Takes more than prescribed
• Runs out early
• Takes the medication without a prescription
• Mixes it with alcohol or opioids
• Has blackouts, falls, or injuries
• Feels unable to function without it
• Has cravings
• Experiences withdrawal symptoms
• Has tried to stop but keeps returning to use
• Has had a near-fatal reaction or emergency

Treatment can address dependence, co-occurring alcohol or opioid use, anxiety, panic disorder, trauma, sleep problems, depression, and relapse concerns. Addiction treatment may include therapy, detox when clinically appropriate, medication management, and structured recovery planning.

Rehab Treatment for Klonopin Addiction

Avoiding Klonopin overdose requires an understanding of the appropriate dose and extreme caution when using other substances or alcohol. Addiction can make it difficult to stop taking Klonopin, even if the risks are known. Klonopin and other benzos generally have a higher risk of addiction, since people can take more to avoid Klonopin withdrawal.

To effectively manage benzodiazepine addiction, treatment in a facility for substance use is recommended. Addiction centers often have different treatment levels, including outpatient, intensive outpatient (IOP), and inpatient/residential. The level of treatment depends on a person’s needs.

For more severe addictions, medical detox may be necessary as the person navigates withdrawal symptoms. Doing this in a treatment center is more likely to lead to better outcomes because the person is under supervision, with additional medication if needed. Medical detox can also include a taper.

If you or someone you know is living with a Klonopin addiction, The Recovery Village Ridgefield can help. Contact us today to discuss treatment options available for Klonopin addiction.

Frequently Asked Questions

Can you take too much?

Yes. Taking too much can happen when someone uses extra pills, uses them too close together, takes medication without a prescription, or mixes it with alcohol, opioids, sleep medications, or other sedatives.

What are the warning signs?

Signs may include extreme drowsiness, confusion, slurred speech, poor coordination, slow breathing, low blood pressure, slow heart rate, vomiting, loss of consciousness, or coma (Kang et al., 2023).

Is there a lethal amount?

There is no single lethal amount that applies to everyone. Fatal danger depends on the amount used, tolerance, age, health conditions, alcohol or opioid use, and how quickly emergency care is received.

Is it usually fatal?

A fatal outcome is more likely when alcohol, opioids, or other sedatives are involved. Clonazepam alone can still be dangerous, especially at high amounts or in people with low tolerance, older age, liver disease, or breathing problems. In CDC data from January–June 2020, most benzodiazepine-involved overdose deaths also involved opioids (Liu et al., 2021).

What should I do after taking too much?

Do not use more medication, drink alcohol, or use other sedatives. Call Poison Control at 1-800-222-1222 if you are awake and stable. Call 911 for slow breathing, severe confusion, loss of consciousness, blue or gray lips, repeated vomiting, or inability to stay awake.

Is it more dangerous with alcohol?

Yes. Alcohol and this medication both slow the central nervous system. Mixing them can increase sedation, poor coordination, memory loss, slowed breathing, coma, and fatal danger. Research on opioid-related fatalities found frequent co-involvement of alcohol and sedatives, reinforcing the danger of combining these substances (Tori et al., 2020).

Is it more dangerous with opioids?

Yes. Opioids and Klonopin can cause profound sedation, breathing failure, coma, and death when used together. This combination should be avoided unless a prescriber determines it is medically necessary and closely monitors the patient (U.S. Food and Drug Administration, 2021).

Will naloxone reverse it?

Naloxone will not reverse clonazepam itself. However, if opioids may be involved, naloxone can reverse the opioid part of the emergency and may save a life. Call 911 even if naloxone is given (Centers for Disease Control and Prevention, 2024).

How is it treated?

Care is usually supportive and may include airway support, oxygen, breathing support, IV fluids, monitoring, and observation. Flumazenil may be considered in select cases but can be risky for people with dependence, seizure disorders, or mixed-substance poisoning (Kang et al., 2023; Shoar et al., 2024).

Can withdrawal be dangerous?

Yes. Withdrawal can cause anxiety, insomnia, tremors, agitation, confusion, and seizures or delirium in severe cases. People who use this medication regularly should talk with a medical professional before stopping suddenly (Brunner et al., 2025).

When should someone seek treatment?

Treatment may be needed if someone takes more than prescribed, mixes the medication with alcohol or opioids, has cravings, experiences withdrawal, cannot stop, or has had a near-fatal reaction.

References

Brunner, E., Chen, C.-Y. A., Klein, T., Maust, D., Mazer-Amirshahi, M., Rastegar, D., Terplan, M., & Lin, L. A. (2025). Joint clinical practice guideline on benzodiazepine tapering: Considerations when risks outweigh benefits. Journal of General Internal Medicine.
Full link: https://pmc.ncbi.nlm.nih.gov/articles/PMC12463801/

Centers for Disease Control and Prevention. (2024). Lifesaving naloxone.
Full link: https://www.cdc.gov/stop-overdose/caring/naloxone.html

Kang, M., Galuska, M. A., & Ghassemzadeh, S. (2023). Benzodiazepine toxicity. StatPearls Publishing.
Full link: https://www.ncbi.nlm.nih.gov/books/NBK482238/

Liu, S., O’Donnell, J., Gladden, R. M., McGlone, L., & Chowdhury, F. (2021). Trends in nonfatal and fatal overdoses involving benzodiazepines — 38 states and the District of Columbia, 2019–2020. Morbidity and Mortality Weekly Report, 70(34), 1136–1141.
Full link: https://www.cdc.gov/mmwr/volumes/70/wr/mm7034a2.htm

Peppin, J. F., Raffa, R. B., Schatman, M. E., & Prommer, E. (2020). The polysubstance overdose-death crisis. Journal of Clinical Medicine, 9(7), 2343.
Full link: https://pmc.ncbi.nlm.nih.gov/articles/PMC7751289/

Shoar, N. S., Bistas, K. G., & Saadabadi, A. (2024). Flumazenil. StatPearls Publishing.
Full link: https://www.ncbi.nlm.nih.gov/books/NBK470180/

Tori, M. E., Larochelle, M. R., & Naimi, T. S. (2020). Alcohol or benzodiazepine co-involvement with opioid overdose deaths in the United States, 1999–2017. JAMA Network Open, 3(4), e202361.
Full link: https://pmc.ncbi.nlm.nih.gov/articles/PMC7146101/

U.S. Food and Drug Administration. (2021). Klonopin prescribing information.
Full link: https://www.accessdata.fda.gov/drugsatfda_docs/label/2021/017533s061lbl.pdf