Emily Doe
Author: Emily Doe Medical Reviewer: Amy Shelby Last updated:

Clonazepam, commonly known as Klonopin, is a benzodiazepine that is primarily used in the treatment of panic disorder and seizures. [1] Clonazepam is a medication that should only be taken when prescribed by your doctor, as misuse of the drug can be dangerous.

Clonazepam brand names

Clonazepam is also known as Klonopin and Rivotril.

What is clonazepam prescribed for?

Clonazepam is mainly used to treat panic disorders and seizures, including epileptic seizures.

This anti-anxiety medication can also be used to treat seasonal affective disorder, epilepsy in adults and children, involuntary muscle spasms (myoclonic seizures) in adults, and restless leg syndrome.

How does clonazepam work?

Clonazepam is a type of benzodiazepine, which is a group of drugs that work in similar ways and are used to treat similar conditions. Benzodiazepines increase gamma aminobutyric acid (GABA) in the body, which is a chemical that prevents panic attacks and seizures by sending signals throughout the nervous system.

How is clonazepam usually taken?

Clonazepam should be taken exactly as prescribed by your doctor. It is taken orally either through a tablet or a dissolvable tablet. The amount of clonazepam prescribed will vary from person to person, depending on the frequency and severity of symptoms, medical history, age, and the form of clonazepam taken.

Clonazepam is usually started on low daily doses and increased until the dose is effective for that individual.

You can take clonazepam with or without food. Try to take clonazepam at the same time each day and avoid missing doses to get the full benefits from the medication.

How long does clonazepam stay in your system?

Clonazepam has a half-life of between 20 and 50 hours, which means that it stays in your body a relatively long time. The effects of clonazepam can last for up to 12 hours, so if you are taking the drug to reduce anxiety, you might need to dose less than some other prescription medications, such as Xanax.

Clonazepam can be detected in the saliva for 5-6 days and up to 30 days in the urine.

Clonazepam side effects

Clonazepam can cause adverse effects and you should be monitored by a doctor whilst taking the medication. [1] Side effects can be mild or severe.

Common side effects

  • Feeling drowsy
  • Dizziness
  • General fatigue
  • Slow reflexes or feeling uncoordinated
  • Memory problems
  • Low mood or depression

Mild side effects may stop after taking the medication for a couple of weeks, although serious allergic reactions are possible, albeit rare. If you have any symptoms of an allergic reaction, or are experiencing severe or long-lasting side effects, you should speak with your doctor immediately.

Serious side effects

  • Depressed mood lasting longer than two weeks
  • Thoughts of self-harm or suicide
  • Seizures (this can also be a side effect from stopping taking this medication too quickly)
  • Slowed or shallow breathing
  • Yellowing of the skin or eyes, which can be a sign of jaundice, possibly indicating a liver problem
  • Hallucinations/delusions
  • Swollen ankles, fast heartbeat, and cough and/or fatigue (may signify heart problems)

If you are having thoughts of suicide or self-harm, call 911 (or the emergency services in your country) if you are in immediate danger.

Withdrawal symptoms and addiction

Clonazepam can be addictive, even if taken as prescribed, and should be taken under medical supervision. It is unlikely to cause addiction if taken for less than 2-4 weeks.

If you miss a dose of clonazepam, or stop taking it completely, you may experience painful physical withdrawal symptoms. Abrupt withdrawal can even be life-threatening depending on the length of time you have taken it, your physical health, and the dose.

Clonazepam precautions

Before taking clonazepam, you should discuss your full medical history with the prescribing doctor, as some medical conditions make it unsafe to take clonazepam. Additionally, some drugs will interact with benzodiazepines (including clonazepam), and increase the risk of dangerous side effects, or even death.

Clonazepam is a central nervous system (CNS) depressant and can lead to impaired judgement and slow reaction times. When you first start taking the medication, it is important to avoid activities that require you to be alert until you know exactly how the medication affects you. This includes activities such as driving, operating machinery, or certain sports like climbing or swimming.

You should never stop taking the drug without support from your doctor. Clonazepam needs to be titrated, which means you should allow for the drug to slowly build up or be released from the body. Ceasing the drug too quickly can lead to withdrawal symptoms, including trouble sleeping or insomnia, feeling irritable, seizures, or even death.

The doctor will monitor you whilst taking clonazepam to make sure you stay safe. They will regularly check your kidney function and mental health, and observe you for seizures.

After taking clonazepam for a long time, you may build a tolerance, rendering the medication less effective. If you feel that the medication has stopped working as effectively, you should talk to your doctor.

Pre-existing conditions

You should avoid clonazepam if you have certain pre-existing conditions, as the drug may make them worse or cause harmful effects. These conditions include:

  • Depression. You should be careful when taking clonazepam if you have depression, as your symptoms may get worse. Clonazepam can cause suicidal thoughts.
  • Liver disease. We rely on the liver to break down substances in the body, including medications. People with liver disease may struggle to clear the body of clonazepam, causing dangerous levels to build up in the body.
  • Acute narrow angle glaucoma. This is an eye condition that is worsened by clonazepam.
  • Sleep apnea. This condition causes you to have breathing issues when sleeping, and can be exacerbated if you take clonazepam.
  • Previous addictive behaviors. [2]
  • You should not take clonazepam if you are going to have an anesthetic, including for dental treatment.

Pregnancy and breastfeeding

If you are pregnant, it is not recommended to take clonazepam unless the potential benefit justifies the risk, as the medication can negatively affect the fetus. This decision will assessed and determined by a medical professional. If you become pregnant whilst taking this medication, do not suddenly stop taking it, as this can cause serious side effects. Instead, speak to your doctor immediately.

You cannot breastfeed and take clonazepam, as the drug passes into the breast milk and can cause harm to the child.

It is recommended that you consult with your doctor if you are planning in becoming pregnant and you currently take clonazepam.

Clonazepam interactions

Clonazepam can interact with other drugs to cause negative side effects. You should discuss all the prescribed, unprescribed, and recreational drugs that you take with your doctor before you are prescribed clonazepam. This includes herbal remedies and vitamins.

Clonazepam vs drugs that cause drowsiness

If clonazepam is taken with other drugs that cause drowsiness such as other benzodiazepines, barbiturates and sleep drugs, and antiepileptic drugs that treat seizures such as gabapentin and pregabalin. It increases the risk of adverse reactions, such as drowsiness, poor judgement, loss of consciousness, or respiratory depression. Taking more than one medication that causes drowsiness at the same time increases the risk of overdose.

Clonazepam vs Opioids

Clonazepam is a CNS depressant, as are opioids. Taking too much of these, or taking them together, can lead to severe symptoms, such as drowsiness, slowed breathing, or even death. Commonly prescribed opioid medications include codeine, tramadol and hydrocodone. If you are prescribed clonazepam with an opioid, you will be monitored by your doctor.

Clonazepam vs Alcohol

Alcohol use whilst taking clonazepam can increase the sedative effects of the medication, including slowed reflexes, lack of coordination, or drowsiness. This can be dangerous, and you should talk to your doctor about your alcohol use if you are taking clonazepam.

Clonazepam vs Street drugs

Using street drugs whilst taking clonazepam can be very dangerous.

Clonazepam and herbal medicines

Avoid taking clonazepam with herbal medicines that could increase drowsiness, such as passionflower or valerian root.

Clonazepam storage

Clonazepam should be stored between 15 and 30 degrees in a dark, dry place. Bathrooms are not appropriate for storing medication, as the humidity and moisture can damage them, causing the oral tablets not to work in the ways that they are intended.

Clonazepam should be stored safely and securely, such as in a high locked cupboard out of reach of others, particularly children and pets. If you do not store clonazepam securely, someone else may accidentally take the medication and come to harm.

What to do if you overdose on clonazepam

If you take more clonazepam than you have been prescribed, it can have dangerous effects on the body. Taking too much can lead to feeling confused, drowsy, having slow reflexes, or becoming unconscious and going into a coma.

If you think you or someone else has taken too much clonazepam, you should seek medical attention immediately. Call 911 (or the emergency service number in your country) if the symptoms are severe.

Frequently asked questions about clonazepam

Clonazepam vs Lorazepam: What’s the difference?

Clonazepam and lorazepam are both benzodiazepines. Lorazepam has a shorter half-life than clonazepam and is known as an immediate-acting medication, which means it can be used to treat anxiety and help with sleep. Clonazepam has a longer half-life, and is prescribed to treat seizures, as well as anxiety.

Clonazepam vs Diazepam: What’s the difference?

Clonazepam and diazepam are both benzodiazepines used to treat anxiety and seizures. Diazepam is more likely to cause addiction and has more severe side effects when withdrawing.

  1. Dokkedal-Silva, V., Berro, L.F., Galduróz, J.C., Tufik, S., & Andersen, M.L. (2019). Clonazepam: Indications, side effects, and potential for nonmedical use. Harvard Review of Psychiatry, 27.
  2. Taipale H, Särkilä H, Tanskanen A., et al. Incidence of and characteristics associated with long-term benzodiazepine use in Finland. JAMA Netw Open. 2020;3(10):e2019029.
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Emily Doe
Author Emily Doe Writer

Emily Doe is a medical writer with 8+ years of experience, holding a Bachelor of Arts (B.A.) degree in English from the University of Leeds.

Published: Nov 9th 2022, Last edited: Sep 22nd 2023

Amy Shelby
Medical Reviewer Amy Shelby M.S. Counseling Psychology

Amy Shelby is a medical reviewer with a B.A. in Psychology from Northwestern and an M.S. in Psychology from Chatham University.

Content reviewed by a medical professional. Last reviewed: Nov 10th 2022