How Long Does Klonopin (Clonazepam) Last?

Updated on March 30, 2026

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.

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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

Signs That Klonopin Use Has Become An Addiction

Because Klonopin is a prescription medication, many people do not realize that dependence and addiction can develop even when the drug is taken as directed. The risk increases significantly when the drug is misused, taken in higher doses than prescribed, or used for longer than intended. Some of the earliest warning signs include needing to take more of the drug to feel the same effects, feeling anxious or physically unwell when a dose is missed, and continuing to use Klonopin despite wanting to stop.

Behavioral signs are equally important to watch for. These can include visiting multiple doctors to obtain additional prescriptions, withdrawing from friends and family, neglecting responsibilities at work or home, and spending significant time and energy obtaining and using the drug. Because Klonopin is a long-acting benzodiazepine, its effects can be subtle and gradual, making it easy for dependence to develop without a person fully recognizing what is happening.

If these patterns sound familiar, reach out to a healthcare provider or addiction specialist to get help.

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.

This page does not provide medical advice. See more

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