Clonazolam is a widely misused designer benzodiazepine that is sold online as a research chemical. Its effects are similar to other benzodiazepines and include sedation, reduced anxiety, and muscle relaxation. Clonazolam is highly potent and has been associated with severe health risks, including respiratory depression, cognitive impairment, coma, and in some instances, fatal overdose. [1][2][3]
- Clonazolam is a designer benzodiazepine that can be purchased online as an unregulated research chemical in many countries around the world.
- Clonazolam is a highly potent and addictive drug that can have life-threatening effects when abused.
- Clonazolam risks include addiction, withdrawal, extreme sedation, coma, overdose, and death.
What is clonazolam?
Clonazolam was first synthesized in 1971, but it was never approved or marketed as a pharmaceutical medication. As a result, it later emerged as a Novel Psychoactive Substance (NPS), often sold online as a “research chemical” in various parts of the world. [1][2]
Clonazolam belongs to a group of substances known as designer benzodiazepines, which are chemically modified versions of existing prescription benzodiazepines. Many of these compounds are significantly more potent than traditional benzodiazepines.
Designer benzodiazepines like clonazolam may carry an increased risk of harmful effects such as dependence, severe withdrawal symptoms, and overdose. In addition, most designer benzodiazepines have not been extensively studied, so their full health risks remain poorly understood. [3]
Clonazolam began appearing in recreational drug markets around 2014. Since then, an increased number of emergency department visits, toxicology investigations, and clonazolam overdoses have been reported. Growing concerns about its potency and public health risks led the DEA to classify clonazolam as a Schedule I controlled substance in 2023, making it illegal to purchase or possess in the U.S. [1][2]
How clonazolam works
Clonazolam is an analog of the drugs alprazolam (Xanax) and clonazepam (Klonopin), and has a similar structure, mechanism of action, and effects. Clonazolam is a central nervous system (CNS) depressant, meaning it slows brain activity to induce sedative, relaxing, and anxiolytic effects. [1][3]
Like other benzodiazepine drugs, clonazolam works by binding to GABA receptors in the brain, acting like a brake pedal to the CNS. Within minutes of taking the medication, users begin to feel drowsy, relaxed, and slower to process information and respond to stimuli. These effects are dose-dependent, and large doses can result in extreme sedation, coma, overdose, and in some cases, death. [1][2]
Clonazolam vs. Prescription benzodiazepines
Because clonazolam is a relatively new drug of abuse, there is not enough research to fully understand its effects, risks, and comparisons to traditional benzodiazepines. There is some research that suggests that the effects of clonazolam are stronger and longer-lasting than traditional benzodiazepines, but this has not been confirmed. [1][3]
Unlike prescribed benzodiazepines, research chemicals like clonazolam are unregulated and don’t go through the same rigorous safety and quality control testing. For example, there is no research that documents a toxic or lethal dose of clonazolam. This places users at increased risk of adverse effects, accidental poisoning, or exposure to harmful contaminants. [3]
For these reasons, clonazolam is considered a Schedule I controlled substance in the U.S., meaning it has no approved medical use and carries significant risks for abuse, addiction, and other health complications. In comparison, most benzodiazepines are Schedule IV controlled substances, meaning they have approved medical uses and carry a much lower risk for abuse, addiction, and health problems.
Effects of clonazolam
The effects of clonazolam are similar to those of other benzodiazepines, but may be stronger and longer-lasting in nature, especially at high doses. In some case studies, it has been reported that the effects of clonazolam can take several hours or even up to a day to wear off. Prolonged sedation has been commonly reported, especially in people who have consumed high doses. [2]
Here are some of the reported effects of clonazolam: [1][2][3]
- Sedation or drowsiness.
- Muscle relaxation.
- Reduced anxiety.
- Cognitive impairment.
- Slowed responsiveness.
- Mental confusion.
- Amnesia.
- Motor impairment.
Intoxication and health risks
Additional research is needed to better understand the health risks associated with clonazolam use and to identify the dose or frequency most likely to produce these harmful effects. The available research is limited to individual case studies that come from emergency departments, rather than from larger-scale studies. [1][3]
From these small samples, the following intoxication and health risks have been reported: [1][2][3]
- Extreme sedation
- Loss of consciousness
- Coma
- Respiratory distress or respiratory depression
- Overdose
- Death
The long-term risks of clonazolam are unknown, as there is not sufficient research on this topic. It is likely that long-term use of clonazolam significantly increases the risk for dependence, addiction, and withdrawals. [1]
Dependence and withdrawal risks
There is no research on the specific addictive potential of clonazolam, but it is likely that it is similar to other benzodiazepines. Benzodiazepines can be addictive, even after only a few weeks of regular use. Because of this, the US Food and Drug Administration added a boxed warning on all prescription benzodiazepines noting their potential to lead to dependence and withdrawals. [4]
Signs of drug dependence (addiction) include: [5]
- Using more often or in higher doses than intended.
- Unsuccessful efforts to cut back, moderate, or stop using.
- Strong cravings, thoughts, or urges to use.
- Needing to use more to get the same effects (tolerance).
- Giving up other recreational or social activities to use more.
- Neglecting responsibilities at work or home because of use.
- Using in situations where it is risky or hazardous.
- Negative effects on physical or mental health related to use.
- Relationship problems related to use.
- Withdrawals when cutting back or stopping.
Withdrawal symptoms
When someone develops an addiction to benzodiazepine drugs, they will experience unpleasant withdrawal symptoms when they cut back or stop using suddenly. Withdrawals can be physical or psychological in nature, and many individuals report a mix of both.
Common withdrawal symptoms include: [6]
- Rebound anxiety or panic attacks.
- Depressive symptoms.
- Increased irritability.
- Trouble sleeping.
- Sweating or chills.
- Shaking, tics, or tremors.
- Nausea or GI pain.
- Perceptual changes.
Withdrawals from benzodiazepines can be dangerous, especially after using the drug at high doses for a long time. Serious signs of withdrawal include psychosis, seizures, and severe agitation. [6]
Counterfeit pill risk
Because designer benzodiazepines like clonazolam are unregulated, there is a significant risk that products purchased online may contain different substances or dosages than advertised. Some individuals treated for clonazolam overdose in ER settings were unknowingly exposed through counterfeit pills obtained online. [2] Specialized laboratory testing, which is generally unavailable to most users, is needed to confirm clonazolam purity and dose.
Signs of overdose and emergency
There have been reports of clonazolam overdose and medical emergencies, including some resulting in coma and death. The signs of clonazolam overdose are similar to those involving other benzodiazepine drugs, and include: [6]
- Extreme sedation, dizziness or confusion.
- Lack of responsiveness.
- Loss of consciousness.
- Shallow, staggered or slow breathing.
- Blue lips or fingertips.
- Severe withdrawals involving seizures.
What to do if someone overdoses on clonazolam
If someone overdoses on clonazolam or another benzodiazepine drug, it is important to seek emergency medical attention. Calling 911 or reporting to your nearest emergency room is necessary to prevent life-threatening complications like respiratory depression or coma. [2][6]
Is clonazolam a controlled substance?
In 2023, the DEA passed a temporary rule to classify clonazolam as a Schedule I controlled substance. This rule was extended in 2025 and made permanent in 2026, making it illegal to purchase, possess, or sell clonazolam in the United States. In many other nations, clonazolam is unregulated and legal to purchase online.
Harm reduction
The best way to prevent risks associated with clonazolam use is to stop using it completely, but this may need to happen slowly and under the supervision of a licensed medical professional. People who have been using heavily, frequently, or for long periods of time may be especially at risk for withdrawal. Consulting with a medical provider on advice for safe tapering is advisable in these situations. [6]
The risk for serious adverse effects, including overdose, is greatly increased when clonazolam is used in combination with alcohol or other drugs, particularly other CNS depressants. Avoiding polysubstance use is another strategy to reduce the potential for serious risks associated with clonazolam use.
Treatment options for problem use
There are many effective treatments for people struggling with an addiction to clonazolam or other drugs. These include therapy, sometimes in addition to medications, which may be provided in inpatient, residential, intensive outpatient, or outpatient settings. The specific type of treatment indicated will depend on a number of factors, including the severity of the addiction.
For most people, the first step in seeking treatment is a substance abuse evaluation provided by a licensed health or mental health provider. During this assessment, you may receive a diagnosis of a substance use disorder and/or other mental health condition. You will also receive information about recommended and available treatments.
Final thoughts
Clonazolam is a potent and highly dangerous designer benzodiazepine associated with serious risks including addiction, withdrawal, overdose, respiratory depression, and death. Because clonazolam is unregulated and poorly studied, users may be exposed to unpredictable doses, counterfeit products, and health effects that are not well understood. [1][2][3]
Although more research on clonazolam is needed, available evidence suggests that its effects may be stronger and longer-lasting than many traditional benzodiazepines. [1][2][3] Similar to other benzodiazepines, it is likely that clonazolam can lead to addiction after a few weeks of regular or heavy use. [4] Once an addiction has formed, users may experience severe withdrawal symptoms that require gradual tapering, in addition to long-term treatment for the underlying addiction. [6]
