How Long Does Klonopin Stay in Your System?

Learn everything you need to know about Klonopin and how long it stays in your system.

Understanding Klonopin

Klonopin is one of a few brand names for clonazepam, a medication used to prevent and treat seizures, panic disorders, anxiety, and akathisia. For this article, we’ll be referring to the drug clonazepam by one of its most popular brand names, Klonopin, and you can learn the answer to the question “how long does Klonopin stay in your system?

Klonopin is a powerful drug and can often be misused. As a result, it is often checked for during drug tests. In addition, there is a lot of online activity for searches, such as:

  • How long does Klonopin stay in your system?
  • What is the Klonopin half-life?
  • How to beat a Klonopin drug test
  • Klonopin drug test detection time
  • Klonopin in urine

A word of caution must be given to anyone abusing this drug and attempting to cheat on urine or blood Klonopin drug tests. Klonopin abuse is hazardous and potentially fatal. Thus, it is crucial to speak to a medical professional immediately if you feel that you or someone you know needs help.

Understanding Klonopin


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What Is Klonopin?

Klonopin, a benzodiazepine, is available as scored tablets with a K-shaped perforation containing 0.5 mg of clonazepam and unscored tablets with a K-shaped perforation containing 1 mg or 2 mg of clonazepam. A normal dose of Klonopin depends on the patient’s condition and specific needs prescribed by a medical professional. 

Each tablet contains lactose, magnesium stearate, microcrystalline cellulose, and cornstarch, with the following colorants: 0.5mg—FD&C Yellow No. 6 Lake; 1 mg—FD&C Blue No. 1 and FD&C Blue No. 2 Lake.

The answer to how long Klonopin remains in your system and its half-life is dependent on several factors, including age, weight, height, and a few others. We will discuss this in depth shortly.1


The precise mechanism of how Klonopin exerts its anti-seizure and anti-panic effects is unknown. Nonetheless, it is believed to be related to its ability to enhance the activity of gamma-aminobutyric acid (GABA), the major inhibitory neurotransmitter in the central nervous system.1

How Long Does Klonopin Take to Work?

Klonopin is rapidly and completely absorbed after oral administration. The absolute bioavailability of Klonopin is about 90% and is approximately 85% bound to plasma proteins. In addition, Klonopin is highly metabolized, with less than 2% unchanged clonazepam being excreted in the urine.1

Klonopin takes approximately twenty to sixty minutes to start working. The peak effects of the active ingredient, clonazepam, may be reached in several days.2 This range is dependent on body weight, height, age, and other factors. 

The Klonopin duration of action is not connected to how long Klonopin stays in the system, and this should not be assumed. It is also not an indication of Klonopin drug test results—more about this shortly.

Important Tips When Taking Klonopin

The following tips can be essential to taking Klonopin safely and properly:3

  • Swallow tablets whole with water.
  • Klonopin is potentially addictive and can cause physical and psychological dependence. Take only as directed by your doctor. 
  • Do not take Klonopin with opioids (be aware that some opioids are contained in over-the-counter cough or cold products). Always talk with your pharmacist or doctor before buying over-the-counter medications to check that they are compatible with Klonopin.
  • Do not drive or operate machinery if Klonopin makes you drowsy or impairs your judgment.
  • Do not drink alcohol while taking Klonopin because this may worsen side effects, such as respiratory depression and sedation.
  • If your mood changes or you develop depression, a worsening of depression, or a worsening of seizures, talk with your doctor.
  • See your GP immediately if you experience Klonopin tolerance symptoms, such as a lessening effect or no effect, see your GP immediately.
  • Do not start or discontinue Klonopin during pregnancy without speaking to your provider first.
  • Women should not breastfeed while taking Klonopin.

Factors That Affect Klonopin Duration and Elimination

For those questioning how long Klonopin stays in your system and what the Klonopin half-life is—we provide answers below. Please remember to be cautious and only use the drug when prescribed for you and as indicated. 

The following factors influence Klonopin duration and elimination:


As age increases, the functions of tissues and organs in the body gradually decline. Due to this decline in organ function, drug absorption, distribution, metabolism, and excretion (ADME processes) in older adults are worse than in young people. 

Furthermore, drug sensitivity is different in the elderly, who have adverse drug reactions. Thus, it is imperative to design medications according to the characteristics of older adults.4


People with serious health issues should be cautious when taking any drug, especially those with high schedules like Klonopin. Patients need to consult closely with their doctor when prescribed this type of medication. 

Anytime your healthcare provider writes a new prescription for you, you should ask a few questions before agreeing to take it. By doing so, you will not only better understand the medication you are taking and how to use it, but you also will learn why you need to take it and what to expect.5

Body Mass Index

The effect of body weight on drug action may vary in extent. In some cases, weight can primarily determine the dosage; in others, the weight effect may be minimal, or dosage can be effected only when weight is combined with other factors.6

Klonopin Drug Testing

Klonopin can be detected in one’s:

  • Blood 
  • Saliva  
  • Urine
  • Hair

A Klonopin drug test includes a glucose test to check blood sugar along with a urine test. Compared to urine samples, blood samples are difficult to alter the results. So, some employers can require the employees to provide a blood sample.

Klonopin Half-Life

Unlike other illegal or medically prescribed drugs, Klonopin’s half-life is very long. Although most of the drug will be excreted as urine, some metabolites will stay in the system. These will eventually show up in a Klonopin medical drug test.

As per a recent study, the Klonopin half-life can extend from twenty to fifty hours, which is how long the drug stays in the body.

Klonopin Employer Drug Tests

The legal statute for the Klonopin drug test may differ from state to state; however, no rule encourages Klonopin drug tests for all employees according to federal law. 

Nevertheless,  an employer can test for Klonopin if it is suspected that an employee is abusing the medication. An employer can also recommend a Klonopin drug test for pre-employment candidates if the particular candidate is under medication. The CPS may require a Klonopin drug test from the parents or guardians and pregnant mothers taking Klonopin if they suspect Klonopin abuse.7

How Long Does Klonopin Stay in Your Body?

Klonopin drug test detection time depends on which type of Klonopin drug test is being administered, along with other factors. 

  • Clonazepam’s major metabolite can stay in the system for twenty-eight to thirty days.
  • Klonopin in urine can be detected for twenty-eight to thirty days.
  • Klonopin can remain in the blood for almost five to fourteen days.
  • With a hair sample, the metabolites can be detected for twenty-one to twenty-six days. The days may vary based on several human factors.
  • With a saliva sample, the metabolites can be detected for up to a week. It may be shorter for some people.
  • Along with these factors, some human factors can also affect the drug test, including the person’s age, gender, weight, urine concentration, sample amount, and test period.7

Klonopin Side Effects and Withdrawal Risks

Klonopin Side Effects and Risks

Apart from the most common questions, such as “How long does Klonopin stay in your system?” and “What is the half-life of Klonopin,” another prevalent online search is regarding the side effects and withdrawal symptoms of the drug.

Klonopin Side Effects

Klonopin Withdrawal Risks

Klonopin is a powerful and potentially addictive drug that should only be administered and taken when prescribed by a medical professional. Nonetheless, Klonopin therapeutic doses can be highly effective for specific conditions and improve millions of lives when taken responsibly.