Clonazepam: Uses, Side Effects, Dosages, and More

Published March 8th, 2021 by Erik Rivera
Fact Checked by
Camille Freking
Medically Reviewed:
Dr. Gerardo Sison
Updated Date: Mar 18th, 2021

Panic disorder is estimated to affect about 2.7 percent of adults in the United States. Left untreated, the condition can be debilitating and lower a patient’s quality of life dramatically. 

One well known treatment for panic disorder is clonazepam, which is a prescription drug that was initially developed for the treatment of seizure disorders. The medication acts on the GABA-benzodiazepine receptor complex and increases the effects of GABA, a chemical that slows down activity in the brain. 

If you are living with panic disorder or seizures that can be treated with clonazepam, here’s everything you need to know about the medication, its side effects, dosage, and more.

What is clonazepam?

Clonazepam belongs to a class of drugs called benzodiazepines, which are typically used to treat acute anxiety symptoms, seizures, and insomnia. Clonazepam is also considered an anticonvulsant or antiepileptic drug and was originally developed for the purpose of treating and preventing certain types of seizures. 

The drug is closely related to other benzodiazepine medications like Ativan (lorazepam), Valium (diazepam), and Xanax (alprazolam). Clonazepam is also sold under the brand name Klonopin and can be purchased in the form of an oral tablet that comes in a variety of strengths. The medication is classified by the U.S. Drug Enforcement Administration (DEA) as a Schedule IV controlled substance because it carries a risk of abuse and addiction.

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What is clonazepam used to treat?

Clonazepam is approved by the U.S. Food and Drug Administration (FDA) for the treatment of anxiety disorders like panic disorder with or without agoraphobia, and it is also used for the treatment of Lennox-Gastaut syndrome and certain types of seizures, including absence seizures. 

Unlike other benzodiazepines, such as Ativan and Xanax, clonazepam is only used to treat symptoms of panic disorder and is not used for the treatment of other types of anxiety or insomnia. 

Absence Seizures

Absence seizures are a type of seizure that typically have a duration of less than 15 seconds in total. Absence seizures are caused by abnormal electrical activity that creates a disruption in normal brain function, causing an affected person to stare off into space without realizing what is happening. Absence seizures are most common in children between the ages of 4 and 12 but typically affect people under the age of 20. This type of seizure typically occurs as a result of overactivity in the brain. 

Lennox-Gastaut Syndrome

Lennox-Gastaut syndrome is a severe form of childhood epilepsy in which the patient can experience a number of different types of seizures. The two types of seizures most commonly associated with Lennox-Gastaut syndrome include atonic, or “drop,” seizures and tonic, or “stiffening,” seizures. 

The symptoms associated with Lennox-Gastaut syndrome are so severe that children with the condition commonly experience intellectual impairment and may exhibit behavioral issues that include aggression, hyperactivity, agitation, and autism. 

Seizures caused by Lennox-Gastaut syndrome are extremely difficult to control and may continue even with treatment. Although most patients are diagnosed with the condition during childhood, it is common for people to experience symptoms and seizures throughout their teenage and adult years.

Panic Disorder

Panic disorder is a type of anxiety disorder that is characterized by the occurrence of panic attacks. Panic attacks are episodes of intense fear and anxiety that come on suddenly and cause significant physical symptoms despite the lack of a clearly identifiable cause or threat. 

The physical symptoms caused by panic attacks can feel so severe that people with the disorder may feel like they are having a heart attack, and it is common for patients to visit the emergency room thinking they are having a heart attack when they experience a panic attack for the first time. 

Many people will experience one or two panic attacks at some point during their lives, but panic disorder is diagnosed in people who regularly experience these episodes without an obvious cause or trigger. 

Symptoms of panic attacks include:

  • Sense of impending doom or danger

  • Nausea

  • Chest pain

  • Hot flashes

  • Abdominal cramping

  • Dizziness, lightheadedness or faintness

  • Rapid, pounding heart rate

  • Trembling or shaking

  • Chills

  • Feeling detached from reality

  • Shortness of breath or tightness in your throat

  • Fear of loss of control 

  • Sweating

  • Headache

  • Numbness or tingling sensation

How long does clonazepam stay in your system?

Most benzodiazepines, including Ativan, Xanax, and Valium, are fast-acting medications that work quickly to reduce symptoms of anxiety but also wear off quickly. By contrast,  clonazepam is a longer lasting benzodiazepine, but the medication does start working quickly. 

After taking a dose of clonazepam, most patients will begin to experience relief of their symptoms within as little as 20 minutes to an hour. The medication reaches its full effect anywhere from one to four hours after a dose is taken. 

Depending on how quickly patients process the drug, they will experience the effects of the medication for anywhere from 6 to 12 hours. Clonazepam’s half life is about 30 to 40 hours, and depending on the size of your dose, the medication may be detected in your system for up to two weeks.

What are the benefits of using clonazepam?

Benzodiazepines like clonazepam do have a number of downsides, but there are also important benefits associated with the use of clonazepam in particular. 

Clonazepam works longer than shorter-acting benzodiazepines like Ativan and Xanax, which means that patients experience calming effects of the drug for a longer period of time and do not need to take the medication as frequently.  

Additionally, clonazepam begins to work quickly, so it is a good option for patients who need a quick reduction in their symptoms but cannot wait for a long-term anxiety medication, such as Lexapro, to start working. When taken as prescribed and used only as directed, clonazepam is an effective medication that can help patients manage their panic disorder symptoms and control and prevent seizures. 

The drug can be prescribed in conjunction with a long-term antidepressant or anti-anxiety medication for use on an as-needed basis. 

How do I use clonazepam to treat panic disorder?

Due to clonazepam’s potential to cause abuse and addiction, the medication should only be taken for short periods of time -- typically no longer than nine weeks. If a patient needs to take clonazepam for a longer period of time, they should do so only with the supervision of a healthcare professional. 

Patients may use clonazepam as a type of “rescue” medication for the treatment of panic attack symptoms while they wait for a longer-term anxiety medication to start working. 

When taken for panic disorder, the typical starting dose for an adult is 0.25 mg taken twice a day for the first three days. After the first three days, your doctor may increase your dose to 0.5 mg taken twice per day. The maximum dose of clonazepam is 4 mg per day. 

Are there any side effects associated with clonazepam?

Common side effects of clonazepam include:

  • Difficulty thinking or remembering

  • Muscle or joint pain

  • Problems with coordination

  • Increased saliva

  • Blurred vision

  • Drowsiness/Sleepiness

  • Unsteadiness

  • Dizziness

  • Frequent urination

  • Changes in sex drive or ability

Serious adverse effects requiring medical attention include:

  • Rash

  • Hives

  • Difficulty breathing or swallowing

  • Swelling of the eyes, face, lips, tongue, or throat

  • Hoarseness

  • Difficulty breathing

Symptoms of psychological and/or physical dependence on clonazepam may include:

  • Body aches

  • Anxiety

  • Depression 

  • Sweating

  • Nausea

  • Muscle weakness

  • Nightmares

  • Vomiting 

If you experience an allergic reaction to clonazepam, you should seek medical attention immediately. Symptoms of an allergic reaction include:

  • Swelling of lips, tongue, or face

  • Rash or hives

  • Trouble breathing or swallowing

  • Rapid heartbeat

Does clonazepam come with any warnings for use?

Clonazepam is associated with several different warnings for use and has the potential to cause serious side effects and dangerous drug interactions. Benzodiazepines, including clonazepam, have the potential to cause respiratory depression when taken in large doses or by patients who have existing respiratory issues. 

Additionally, the combination of benzodiazepines like clonazepam with central nervous system depressants (CNS depressants) has the potential to cause severe respiratory depression. Medications commonly associated with this drug interaction include opioid painkillers, barbiturates, and other benzodiazepines that are used simultaneously with clonazepam.  

Clonazepam is known to be potentially addictive and can contribute to dependence on the drug when used over an extended period of time or at a higher dose than prescribed, particularly in people with known substance abuse issues. Therefore, it is recommended that patients use clonazepam for the shortest amount of time possible and at the lowest possible dose that is effective at managing their symptoms.

Patients should never discontinue their use of clonazepam or change their dose without first seeking medical advice, as the drug can cause severe withdrawal symptoms in patients who do not give their bodies time to adjust. Worsening suicidal thoughts and behaviors is one potentially life threatening symptom of clonazepam withdrawal. 

Individuals taking antihistamines, muscle relaxers, certain antifungals, or other antidepressant medications should speak to their doctor or pharmacist before using clonazepam due to the potential for dangerous drug interactions to occur. 

Patients with liver disease or narrow angle glaucoma should discuss their medical history with their healthcare provider and may need to take a lower dose of the drug. Additionally, pregnant women and those breastfeeding should not take clonazepam as it can pass into breast milk.

Are there any withdrawal symptoms associated with clonazepam?

Clonazepam is known to cause withdrawal symptoms in patients who have been taking the drug for more than two weeks and who abruptly stop or decrease their dose dramatically. 

If you have been taking clonazepam for more than two weeks, make sure you speak to a healthcare provider before changing your dose of the drug in order to prevent withdrawal symptoms from occurring. 

Common physical withdrawal symptoms include:

  • Headache

  • Irregular heart rate or heart palpitations

  • Fatigue

  • Tremors

  • Insomnia

  • Impaired coordination and motor functions

  • Dizziness

  • Blurred vision

  • Muscle spasms and cramps

  • Feeling lightheaded

  • Stomach pain

  • Sweating

  • Diarrhea

  • Seizures

Common psychological withdrawal symptoms include:

  • Anxiety

  • Difficulty concentrating

  • Hallucinations

  • Confusion

  • Anger and hostility

  • Nightmares

  • Depression

  • Panic attacks

  • Short-term memory lapses

  • Irritability

  • Distorted perceptions of reality

Is it possible to overdose on clonazepam?

While it is rare for patients to overdose on clonazepam alone, it is possible. Overdose most commonly occurs when clonazepam is taken while drinking alcohol or when used in conjunction with opioid medications. 

People who abuse clonazepam or take the drug for longer than it is intended may start taking higher and higher doses of the medication in order to receive the same effects. 

Increasing the dose of clonazepam may eventually lead to an accidental overdose, which is why clonazepam should only be taken as prescribed and under the supervision of a doctor. 

Signs of a clonazepam overdose include: 

  • Confusion

  • Muscle weakness

  • Weak or shallow breathing 

  • Slow heartbeat

  • Extreme drowsiness

  • Lightheadedness

  • Slurred speech

  • Loss of balance or coordination

  • Coma

Medical attention should immediately be sought in the event of an overdose or possible overdose of clonazepam.


Clonazepam is an effective treatment option for panic disorder and certain types of seizures. Compared to other drugs in its class, clonazepam is a longer acting medication and does not need to be taken as often as medications like Ativan or Xanax. 

Clonazepam carries a potential for abuse and addiction and can cause potentially dangerous withdrawal symptoms when use of the medication is stopped abruptly. 

Patients can save on the cost of generic clonazepam or brand name Klonopin with a pharmacy discount card from USA Rx.


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