How Long Does Klonopin (Clonazepam) Last?

Medically Reviewed by Johnelle Smith, M.D. on March 22, 2023

Klonopin is a benzodiazepine medication that is commonly prescribed to treat anxiety, panic, and seizure disorders. There are several factors that may influence the length of Klonopin’s effects.

How Long Klonopin Lasts

Clonazepam, also known by the brand name Klonopin, is a prescription benzodiazepine (benzo) drug used to treat anxiety and panic disorders. Klonopin’s effects can last up to 12 hours.

Due to some potential for abuse, dependence, and addiction, Klonopin is currently classified as a Schedule IV controlled substance by the Drug Enforcement Administration (DEA).

How long drugs last in the body varies depending on a number of factors including drug half-life, food consumption, metabolic rate, frequency of use, and more.


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What Determines The Length Of A Klonopin High?

The effects of most benzos, including central nervous system depressants (CNS) Xanax, Ativan, Restoril, and Valium, last anywhere from three to four hours.

Clonazepam is known to last much longer due to its comparatively long half-life. Typically, it takes two to three days for 50% of Klonopin to be eliminated from the body.

Other factors that influence how long Klonopin stays in the body include:

  • age of the person using Klonopin
  • height
  • weight
  • genetic dispositions
  • polysubstance abuse (abusing more than one illicit or
  • prescription drug at the same time)
  • liver function
  • dosage
  • duration of use
  • length of time since the last dose of Klonopin
  • tolerance level

Methods for detecting Klonopin in a person’s body include saliva tests, blood tests, hair tests, and urinalysis testing.

How Method Of Administration Effects The Length Of A Klonopin High

While clonazepam is typically taken orally in pill form, people who abuse Klonopin may begin using the drug in other ways to feel the effects more quickly and intensely.

Snorting Klonopin

Snorting Klonopin is accomplished by crushing clonazepam pills into a fine powder and inhaling it through the nasal passage.

This method of abuse allows a person to feel the euphoric effects of Klonopin much faster, as it bypasses the digestive system.

Plugging Klonopin

Rectal insertion, also known as “plugging” Klonopin, is done by dissolving the substance into a liquid and injecting it into the rectum with a syringe.

While this method of use will cause a more intense high, it is also very dangerous due to the bioavailability of the drug, which increases the risk of overdose and prescription drug addiction.

Effects Of Klonopin Abuse On The Mind And Body

There are several short-term and long-term side effects that may result from chronic use of clonazepam.

Short-Term Effects Of Klonopin

The most common short-term effects of Klonopin include relaxation in the mind and reduction of anxiety, mild euphoria, and drowsiness.

People can quickly develop a tolerance to clonazepam, which may entice some people to adjust their dosage so they can feel the pleasurable effects of the drug.

Long-Term Effects Of Klonopin

When misused over time, people may develop Klonopin addiction and physical dependency.

Side effects of long-term Klonopin abuse may include:

  • dizziness
  • fainting spells
  • heaviness in the extremities
  • impaired cognition
  • confusion
  • reduced sex drive
  • suicidal ideation

Dangers Of Long-Term Klonopin Addiction

Taken as directed by a doctor, Klonopin can be a safe and effective medication. When misused, however, there is a range of health risks involved.

Risks of clonazepam abuse include:

  • doctor shopping
  • life-threatening Klonopin overdose
  • delirium
  • coma
  • slurred speech
  • clonazepam dependency
  • dangerously low blood pressure
  • reduced judgment
  • slowed reaction time

Klonopin Withdrawal Symptoms

Below are some of the withdrawal symptoms that may occur when someone who has been abusing Klonopin suddenly stops taking the drug.

Withdrawal symptoms may include:

  • shortness of breath
  • nausea
  • mood swings
  • increased anxiety
  • agitation
  • depression
  • shakiness

Many people who abruptly stop taking clonazepam and other antidepressants will experience a health condition called a rebound effect.

The rebound effect will result in an intense resurgence of symptoms that the drug was intended to treat including anxiety, agitation, and nervousness.

How To Treat Klonopin Addiction

Benzodiazepine addiction is serious, but help is available at a substance abuse treatment center.

Behavioral healthcare services for Klonopin abuse may include:

  • medically supervised Klonopin detox
  • cognitive behavioral therapy (CBT)
  • dual diagnosis treatment
  • aftercare services
  • drug tests
  • inpatient or residential treatment
  • intensive outpatient programs (IOP)

The amount of time a person must spend at a rehab center will vary depending on the severity of the addiction, the presence of co-occurring mental disorders, and their overall health.

Find Substance Use Disorder Treatment Today

Call our helpline today for more information on Klonopin addiction treatment programs in your area. Our team can assist you or your loved ones in your journey to long-term recovery.

This page does not provide medical advice. See more

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Medically Reviewed by
Johnelle Smith, M.D. on March 22, 2023


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