How Long Does Klonopin Stay in Your System?

Woman about to take klonopin pill with a glass of water

Klonopin is the brand name for clonazepam, which belongs to the benzodiazepine class of drugs. Because the length of time that Klonopin stays in the system can vary depending on factors like metabolism, extent of use and length of use, it can take anywhere from four to 14 days to leave the system completely. However, Klonopin may be detectable on some drug tests for longer than 14 days. 

Duration of Effects of Klonopin

Klonopin starts working in about one hour, and the effects can last as long as 12 hours. Klonopin accumulates in the body, and taking a lot of the medication can cause doses to “stack.” Taking high doses of Klonopin can cause it to stay in the system for longer.

Klonopin Half-Life

The half-life of a drug is the amount of time it takes for half of the drug to be eliminated from a person’s system. The half-life of Klonopin is between 20–60 hours. With a half-life this long, it typically takes about 13 days to metabolize in the body completely.

How Long will Klonopin Show in Drug Test?

Klonopin drug tests do not look specifically for Klonopin but instead look for shared benzodiazepine metabolites. Drug tests are most effective at finding the metabolites of other benzodiazepines like chlordiazepoxide, diazepam, oxazepam and temazepam.

While Klonopin is detectable in drug tests, it tends to produce a high rate of false-negatives. Drug tests have a harder time picking up Klonopin use because it has a unique set of metabolites.

Klonopin drug test detection times range from a few weeks to over a month, depending on the type of test.

  • Urine: Klonopin is detectable in urine for over 30 days.
  • Blood: In theory, Klonopin should be detectable in the blood for as long as it takes the drug to metabolize, which takes .approximately 13 days
  • Saliva: Klonopin is detectable in saliva drug tests for approximately 5–6 days. However, saliva tests for benzodiazepines are fairly uncommon and must be ordered specifically.
  • Hair: Hair tests measure the deposition of the drug into growing hair. Therefore the detection window is based on how fast hair grows. Hair tests take three months of hair growth, or 1.5 centimeters, and can usually detect Klonopin use in the past 90 days.

Factors Affecting How Long Klonopin Stays in Your System

Clonazepam stays in the body for at least 13 days, but this window increases based on several factors.

Heavy and frequent usage will increase detection times and extended-release formulations may be detectable for longer periods. Klonopin will also stay in the system longer for older people and those with liver problems.

Other factors that affect how long Klonopin stays in your system include:

  • Amount used
  • Age
  • Frequency of use
  • Formulation
  • Method of use
  • Overall health

False Positives for Klonopin

The following drugs are known to cause false-positive benzodiazepine results:

  • Efavirenz
  • Oxaprozin
  • Sertraline

If a drug test returns positive, it will be sent to another lab to confirm the positive results. The specimen will be tested with gas chromatography/mass spectrometry (GC-MS). GC-MS is very sensitive and specific and can detect the “fingerprint” of individual drugs.

Note that Klonopin has a high false-negative rate and will often not show up on tests for benzodiazepines. False-negatives are more likely with lower and less frequent use of Klonopin.

How to Get Klonopin Out of Your System

Klonopin is broken down by the liver. Because of this, people with liver dysfunction may metabolize Klonopin more slowly, meaning that it may stay in their system longer. The only way to remove Klonopin from the body is time. The body must metabolize and remove it naturally. There is no safe and healthy way to speed up this process.

Key Points: How Long Does Klonopin Stay in Your System?

  • Klonopin is prescribed for seizure and panic disorders
  • Since Klonopin can be abused, many workplaces will test for it
  • Klonopin drug tests are designed to test for the drug class benzodiazepine and not Klonopin specifically
  • Klonopin stays in the body for several weeks but can go undetected on many drug tests

If you or someone you know needs help with a Klonopin addiction, call The Recovery Village Ridgefield. We have teams of addiction professionals that can help you learn about treatment options that best fit your needs.

DailyMed. “Clonazepam Package Insert.” 2019. Accessed Aug 4, 2019.

Moeller, Karen E., et al. “Clinical Interpretation of Urine Drug Tests.” Mayo Clinic Proceedings, May 2017. Accessed Aug 4, 2019.

Nordal, Kristin, et al. “Detection Times of Diazepam, Clonazepam, and Alprazolam in Oral Fluid Collected From Patients Admitted to Detoxification, After High and Repeated Drug Intake.” Therapeutic Drug Monitoring, 2015. Accessed Aug 4, 2019.

‌Psychemedics. “Hair Drug Testing Facts.” 2015. Accessed Aug 4, 2019.

Medical Disclaimer: The Recovery Village aims to improve the quality of life for people struggling with a substance use or mental health disorder with fact-based content about the nature of behavioral health conditions, treatment options and their related outcomes. We publish material that is researched, cited, edited and reviewed by licensed medical professionals. The information we provide is not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be used in place of the advice of your physician or other qualified healthcare provider.