≡ Menu

How Long Does Klonopin (Clonazepam) Stay In Your System?

Klonopin (Clonazepam) is a benzodiazepine medication utilized primarily for the treatment of anxiety disorders and acute epilepsy.  It is also prescribed off-label for a host of other medical conditions including: acute mania, akathisia, bruxism, insomnia, and restless leg syndrome.  As a benzodiazepine, it functions principally by modulating the neurotransmission of GABA (gamma-aminobutyric acid) within the brain.

In particular, the GABAergic modulation is attained as a result of clonazepam’s ability to bind to GABAA receptors.  This occupancy of GABAA receptors facilitates an increase in the opening of chloride ion channels, which in turn enhances the effect of endogenous GABA activity.  As a result, users of Klonopin tend to feel significantly more relaxed (mentally and physically), sedated, and/or drowsy.

Although Klonopin and other benzodiazepines may be beneficial on a short-term basis, frequent long-term ingestion may yield deleterious effects.  For example, there is research suggesting that benzodiazepines are linked to dementia, that they can impair learning/memory, cause depression, and significantly compromise job (or school) performance.  As a result of these effects, many individuals have opted to stop Klonopin and hope to clear the drug from their system.

How long does Klonopin stay in your system after stopping?

If you’ve stopped taking this drug, you’re likely going to experience a cornucopia of Klonopin withdrawal symptoms.  If you haven’t yet ceased usage of Klonopin, it is important to only discontinue under medical supervision – abrupt discontinuation is considered dangerous.  In any regard, assuming you’ve taken your final dose of the drug, you’re probably wondering how long Klonopin stays in your system.

To determine how long it is likely to remain in your body following your final dose, it is necessary to consider the half-life of Klonopin’s active ingredient, clonazepam.  Clonazepam has a long elimination half-life within the range of 30 to 40 hours.  This means that it will take between 1 and 2 days just to have eliminated 50% of the drug from systemic circulation.

Based on the 30 to 40 hour half-life estimation of clonazepam, we can estimate that Klonopin is likely to stay in your system for 6.88 to 9.17 days after your final dose.  Other sources suggest that clonazepam may have a wider ranging half-life between 18.7 hours to 60 hours.  If this is the case, it could take between 4.29 and 13.75 days for complete Klonopin excretion.

Furthermore, it is necessary to understand that as clonazepam is metabolized within the liver, it forms a metabolite known as “7-aminoclonazepam.”  Most speculate that the half-life of 7-aminoclonazepam is either shorter than, or similar to that of clonazepam.  For this reason, your body should have cleared Klonopin, as well as its 7-aminoclonazepam metabolites within 2 weeks of cessation.

  • Source: https://pubchem.ncbi.nlm.nih.gov/compound/clonazepam
  • Source: http://www.ncbi.nlm.nih.gov/pubmed/1233263
  • Source: http://www.ncbi.nlm.nih.gov/pubmed/16239362

Variables that influence how long Klonopin stays in your system

On average, Klonopin and its metabolites are thought to be excreted from a person’s system within 14 days of discontinuation.  However, the “average” time for complete excretion is often subject to significant variation.  Variables that are thought to influence excretion speed include: the individual who took Klonopin, the dosage ingested, term of administration, as well as co-ingestion of other substances.

  1. Individual factors

Two people may take just a single 1 mg dose of Klonopin at the exact same time, yet the drug may stay in the system of one individual for significantly less time than the other.  Differences in time of systemic circulation are largely influenced by individual factors such as: a person’s age, body mass, genetics, and hepatic function.

Age: It could be speculated that age is likely to play a role on how long Klonopin stays in your body post-ingestion.  It is understood that elderly individuals (over 65) exhibit slower clearance rates of other benzodiazepines compared to younger adults.  One study documented that elimination half-life of lorazepam in the elderly was approximately 1.8 hours longer than that of younger adults.

Furthermore, systemic clearance of the drug was 22% reduced in elderly individuals compared to non-elderly adults.  For this reason, it is logical to conclude that Klonopin and its metabolites may linger for a longer duration among elderly individuals compared to adults and adolescents.  The longer half-life and decreased clearance may be due to age-related changes such as: decreased hepatic blood flow, reduced plasma proteins, other health problems/medications, and/or poorer physiologic function.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/36252

Body mass + Fat (%): In most cases, the greater your body mass (height/weight) relative to the dosage of Klonopin your take – the quicker you should excrete it.  Individuals who are larger in size can usually metabolize and excrete drugs (of equal dose) faster than those who are smaller sized.  In other words, if a 6’5″ man was taking 1 mg of Klonopin – he would likely metabolize and excrete it faster than a 4’1″ woman taking the same dose.

In addition to body mass relative to dose, body fat percentage should also be considered.  Klonopin is known to be highly lipophilic, meaning it is soluble in fat and can accumulate within fat stores throughout the body.  Therefore, someone with a high body fat percentage will likely retain more clonazepam (and its metabolites) for a longer duration than a person with a low body fat percentage.

Genetics: Variation in alleles is thought to influence the speed by which clonazepam is metabolized and excreted.  Since clonazepam is thought to be metabolized by CYP3A4 isoenzymes within the liver, CYP3A4 variants could result in faster-than-average or slower-than-average metabolism.  A person who metabolizes the drug poorly may retain it for longer than usual with an increased elimination half-life.

Though CYP3A4 variants may play influence excretion speed, NAT2 variants may as well.  A small percentage of the population has mutations of the NAT2 gene, which could extend the duration over which clonazepam is retained prior to excretion.  Should someone be a poor CYP3A4 metabolizer and have a suboptimal NAT2 mutation – they may retain the drug for weeks longer than a person with normative CYP3A4 and NAT2 expression.

Food intake: Simultaneous ingestion of food along with Klonopin may prolong its absorption.  The extent to which absorption is prolonged may depend on the size of the meal and possibly the type of food consumed.  Assuming food ingestion prolongs absorption, a person who ate a meal with their final Klonopin dose may take longer to excrete it than someone who took their last dose on an empty stomach.

Hepatic function: Individuals with hepatic impairment may metabolize clonazepam less efficiently than those with normative liver function.  This is due to the fact that hepatic impairment interferes with enzymatic function, particularly CYP3A4 function. Should a person with a condition like cirrhosis ingest clonazepam, ability to metabolize clonazepam will likely be compromised.

Compromised metabolism leads to greater accumulation of the drug and a slower excretion rate.  For this reason, individuals with hepatic impairment are often instructed to take lower average doses than others.  The extent to which elimination half-life of Klonopin is affected by liver function may be due to the degree of impairment.

Metabolic rate: A person’s BMR (basal metabolic rate) is known to influence metabolism and excretion speed of drugs.  Literature suggests that individuals with high BMRs tend to metabolize and excrete drugs substantially quicker than those with low BMRs.  If you have a high BMR, it essentially means your body is burning more energy at rest.

The increased energy expenditure at rest is thought to facilitate faster breakdown of certain drugs.  If you have a low BMR, your body is burning less energy at rest, and therefore may take longer to excrete Klonopin.  Furthermore, since high BMR is often correlated with low body fat percentage (and vice versa) – and Klonopin is stored in body fat – those with high BMRs are likely to excrete the drug at a faster pace.

Urinary pH: A person’s urinary pH is thought to also influence how long Klonopin stays in their system.  Individuals with a low urinary pH, characterized by acidic urine, are thought to exhibit the fastest clearance speeds.  In other words, acidic urine is thought to maximize the rate of clonazepam clearance, as well as the amount that is excreted.

Individuals with a high urinary pH, characterized by alkaline urine, are thought to exhibit slower clearance speeds.  This is due to the fact that alkaline urine allows clonazepam to get reabsorbed prior to excretion.  Reabsorption resulting from alkaline urine may substantially increase the elimination half-life of clonazepam, whereas acidic urine may decrease it.

  1. Term of Administration

The duration over which someone has taken Klonopin can affect how long it stays in their system following their final dose.  A person that has taken Klonopin consistently for over a year will likely exhibit an increased elimination half-life of clonazepam compared to someone who took it for just a few days.  As a result of clonazepam’s lipophilicity, long-term users will accumulate a significant amount of the drug within bodily tissues.

Short-term users, on the other hand, are unlikely to have accumulated as much of the drug within their tissues.  Someone that used just a single dose of the drug or a person who took it for just a couple days wouldn’t have even reached steady state concentrations.  Steady state concentrations of the drug within the bloodstream are attained within 5 to 7 days of dosing.

This indicates that if you used the drug for under 5 days, you’ll probably clear it from your body faster than someone who’s been using it for a longer duration.  In addition to greater accumulation within bodily tissues of long-term users, most individuals taking Klonopin for an extended period are on high doses.  This is due to the fact that tolerance is rapidly established on benzodiazepines, resulting in constant upward titrations in dosing.

Both increases in dosing and neurophysiological tolerance are associated with an increase in the elimination half-life of drugs.  Since a short-term user is unlikely to have built up significant tolerance, and is likely to be taking a low dose, the drug will be excreted quicker from their system.  Long-term, frequent users may take over 2 weeks for complete systemic clearance of clonazepam.

  1. Dosage (Low vs. High)

It is understood that the dosage of Klonopin taken can affect its elimination speed.  Someone who takes a single dose of 0.25 mg will likely excrete it quicker than a person taking 4 mg per day.  This is because at higher doses a larger quantity of the drug undergoes metabolism within the liver, leading to less efficient metabolic breakdown.

Reduction in efficiency of metabolic breakdown leads to an increased elimination half-life.  The liver is only capable of metabolizing a certain amount of the drug at a time.  When a low dose is administered, CYP3A4 enzymes aren’t overtaxed and clonazepam is efficiently processed.  However, when a high dose is administered, a greater burden is placed on liver enzymes and the drug’s metabolism is slowed.

Additionally, a high dose means that more of the clonazepam will circulate throughout the body (along with its metabolites).  A greater amount of circulating clonazepam leads to increased accumulation within fat stores, and also a greater total amount to excrete.  Those taking low doses are unlikely to accumulate clonazepam to the extent of high dose users and should have a reduced amount to excrete – resulting in quicker elimination.

  1. Co-administration of drugs (CYP3A4)

If you took another drug (or supplement) along with Klonopin, it is necessary to realize that the other substance may affect its metabolism.  Since clonazepam is speculated to be metabolized by CYP3A4 isoenzymes, drugs that affect CYP3A4 function may affect how long it stays in your system.  Certain drugs, known as “inhibitors” of CYP3A4, interfere with isoenzymes responsible for metabolizing clonazepam.

Examples of CYP3A4 inhibitors include: Chloramphenicol, Clarithromycin, Indinavir, Ketoconazole, Nelfinavir, Ritonavir, and Saquinavir.  The aforementioned agents will likely prolong excretion times of clonazepam (and its metabolites) with some variation based on the dosage administered and specific substance.  Other agents, known as “inducers” of CYP3A4, enhance isoenzymes in the liver responsible for metabolizing clonazepam.

Various examples of known CYP3A4 inducers include: Carbamazepine, Efavirenz, Modafinil, Phenytoin, Pioglitazone, Rifampicin, and St. John’s wort.  Should you have taken a CYP3A4 inducer, you’ll metabolize clonazepam at a faster rate, and as a result, should also excrete it more quickly.  Understand that variability in enzymatic induction may be related to the dosage and specific CYP3A4 inducer administered.

Klonopin (Clonazepam): Absorption, Metabolism, Excretion

Following ingestion of Klonopin, the pharmacologically active ingredient clonazepam is rapidly and extensively absorbed by the gastrointestinal (GI) tract.  As a result, clonazepam is documented as having a bioavailability of approximately 90%.  Research suggests that following administration of a 2 mg oral dose, blood concentrations peak (between 6.5 to 13.5 ng/ml) within 1 to 2 hours post-ingestion in healthy adults.

Additional research indicates that peak blood concentrations may be reached between 4 and 8 hours in other individuals.  Healthy adults taking 6 mg of clonazepam daily (in the form of three separate 2 mg doses) are thought to attain plasma concentrations between 20 and 80 ng/ml.  Around 85% of a clonazepam dose binds to plasma proteins, and due to its lipophilic properties, it may be extensively distributed throughout the body.

Upon distribution, the drug is capable of binding to fat stores and accumulating within tissues.  Steady state concentrations of clonazepam are thought to be attained within 5 to 7 days of consistent administration.  Though the metabolism of clonazepam isn’t fully elucidated, it undergoes nitroreduction acetylation via hepatic enzymes CYP3A4 and NAT2.

Some sources imply that CYP3A4 facilitates the conversion of clonazepam to its primary metabolite 7-aminoclonazepam.  The 7-aminoclonazepam metabolite is then converted via NAT2 enzymes to form a secondary conjugated metabolite known as “7-acetaminoclonazepam.”  A majority clonazepam is excreted via urine in the form of metabolites, conjugated glucuronides, and conjugated sulfates.

Less than 2% of an ingested dose will be excreted as unchanged clonazepam.  Elimination of Klonopin (and its metabolites) is subject to variation based on the half-life spanning from 18.7 to 60 hours.  A majority of users will have excreted Klonopin in less than 10 days, but others may take up to 14 days.  Nearly all users will have cleared the drug from their system after 2 weeks of cessation.

  • Source: https://pubchem.ncbi.nlm.nih.gov/compound/clonazepam
  • Source: https://www.pharmgkb.org/pathway/PA165111375
  • Source: http://paindr.com/wp-content/uploads/2015/10/Revised-BZD_-9-30.pdf

Types of Klonopin Drug Tests

If you took Klonopin, there are several types of drug tests that could be administered to detect the presence of clonazepam and its metabolites.  Examples of drug test modalities capable of detecting Klonopin include: urine tests, hair tests, saliva tests, and blood tests.  Most standardized drug tests such as the SAMHSA-5 panel will not screen for benzodiazepines like Klonopin, but extensive panels are capable of detection.

Urine tests: A urine test involves collection of a fresh urine sample that is sent to a laboratory and screened for Klonopin metabolites.  Since less than 2% of a clonazepam dose is excreted unchanged within urine, most urinalyses will assess levels of its metabolite 7-amino-clonazepam (7-ACLO).  Some sources suggest that the 7-amino-clonazepam metabolite remains detectable within urine for up to 5 days post-ingestion.

However, more prominent sources suggest that the 7-ACLO metabolite can be detected for a much longer duration within urine.  One study reported that gas chromatography/mass spectrometry (GC/MS) detected significant amounts of 7-ACLO – in a majority of 1 mL urine samples – 21 days (3 weeks) post-ingestion.  An outlier in the study retained detectable levels of 7-ACLO for over 28 days after ingestion.

Due to the long window of detection associated with urine tests, they are often preferred over blood tests.  Furthermore, urine tests are considered convenient, non-invasive, and fast.  Based on detectability of metabolites for nearly 30 days in a single dose user, higher-dose/chronic users may test positive for 7-ACLO for over month after their last dose.

  • Source: http://paindr.com/wp-content/uploads/2015/10/Revised-BZD_-9-30.pdf
  • Source: http://www.ncbi.nlm.nih.gov/pubmed/12845398

Hair tests: A collection of hair follicles from a person’s head (or other body parts) is capable of determining whether they’ve ingested clonazepam.  A prominent advantage of utilizing hair tests to detect clonazepam ingestion is that they provide a long window of detection.  Research shows that hair tests are able to detect clonazepam’s chief metabolite “7-ACLO” for a period of up to 4 months following administration.

Perhaps a disadvantage of hair tests is that they are sometimes inaccurate in detecting a very recent ingestion of clonazepam.  In other words, if someone had taken the drug today (or yesterday) and had a hair test an hour from now, the drug nor its metabolites would be likely appear in hair outgrowths.  It can take days or weeks after ingestion for the 7-ACLO metabolites to appear within proximal hair segments.

That being said, one study found that 7-ACLO metabolites appeared in hair outgrowths within just several hours of ingestion.  For this reason, hair testing may be used by law enforcement agents to detect clonazepam administration in the case of a drug-related crime.  This involves collecting a hair sample (15-20 follicles) of a victim and sending it for lab analysis with gas chromatography/mass spectrometry (GC/MS) to detect 7-ACLO content in pg/mg.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/12423002
  • Source: http://www.ncbi.nlm.nih.gov/pubmed/15451083

Saliva tests: An oral fluid (salivary) sample can be collected from a person’s mouth, and assessed in a lab for the presence of clonazepam and its metabolites.  Cutoff levels to avoid a false positive are considered 1 ng/ml of clonazepam, which is significantly less than that in a urine sample (30 ng/ml).  Research suggests that clonazepam and 7-ACLO metabolites are only capable of being detected in a saliva sample for between 5 and 6 days after ingestion.

Assuming you’re subject to a saliva test, an oral fluid sample of approximately 0.4 ml may be collected from your mouth.  This sample will be then diluted with around 0.8 ml of a preservative and analyzed with liquid chromatography/mass spectrometry (LC/MS).  Unfortunately the ability to detect 7-ACLO metabolites in oral fluid is considerably reduced compared to other forms of testing.

Although a saliva test is convenient and non-invasive, its accuracy may be suboptimal for detection of clonazepam metabolites. That said, clonazepam and its 7-ACLO metabolites is thought to appear within oral fluid during intoxication.  For this reason, saliva testing has been suggested as an alternative to urine testing in cases of acute intoxication or abuse.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/17725884
  • Source: http://www.ncbi.nlm.nih.gov/pubmed/25549207

Blood tests: It is easiest to detect clonazepam within a blood sample collected approximately 1 to 2 hours after ingestion because this is when levels peak.  Smaller amounts of clonazepam will be detectable well before its peak – likely within minutes of administration.  Following peak levels in the bloodstream, clonazepam content will decrease, but should still remain easily detectable.

Due to clonazepam’s long half-life, it will likely be detectable within a blood sample for days after ingestion.  Furthermore, since it is highly lipophilic and is stored in bodily tissues, trace amounts may appear within the bloodstream for longer durations.  Despite the fact that a blood test may seem like an effective way to detect clonazepam – it provides a shorter window of detection compared to urine testing.

Additionally, blood tests are significantly more invasive than urine testing.  As a result of its drawbacks in detection time and invasiveness, other testing modalities may be preferred.  For this reason, a blood draw to detect clonazepam may be reserved for a hospitalized patient or individuals in a scenario where a urine sample cannot be attained.

Who may get tested for Klonopin?

Although Klonopin (and benzodiazepine) testing is uncommon, certain individuals are more likely to get tested than others.  Individuals that are most likely to get tested include: pilots, truck drivers, military troops, and drug addicts.  Others that may be subject to random testing include: top-level athletes and criminals.

  • Athletes: A high-level collegiate, professional, or Olympic athlete may be subject to extensive drug testing panels. Though extensive drug tests are not common due to their additional cost, in rare cases they may be administered.  Though taking Klonopin isn’t considered a performance enhancer, it may reduce performance anxiety – which could be viewed as an advantage.
  • Criminals: If a law enforcement agent suspects that a criminal may have ingested a sedative or hypnotic agent, the criminal may be tested for benzodiazepines and non-benzodiazepines (Z-drugs). If the individual tests positive for clonazepam or its 7-ACLO metabolites, he/she may face additional jail time and/or sentencing, especially if attained without a medical prescription.
  • Drug addicts: Individuals at rehabilitation facilities are often trying to stay sober and are tested extensively for drug ingestion. Workers at these facilities are aware of the fact that many drug addicts will do whatever they can to find their next “high,” including abusing prescription benzodiazepines like Klonopin.  Should an addict in rehab test positive for clonazepam on a drug test, he/she may necessitate a longer stay at the clinic.
  • Employees: Certain occupations require optimal alertness and vigilance or the consequences could be disastrous. For this reason, it is necessary to ensure that truck drivers, pilots, and those operating heavy machinery abstain from sedatives and hypnotic agents.  These occupations are regularly tested for the presence of CNS depressants and if they’re caught with a drug like clonazepam in their system, they’ll immediately lose their job.
  • Hospital patients: A hospital patient may be tested for benzodiazepines in the case of a suspected overdose and/or for general medical information. For example, a doctor may want to know how much clonazepam is circulating throughout a person’s system after their dosing as to avoid contraindications with another drug.
  • Military troops: Individuals in the military are required to maintain peak mental alertness for a variety of reasons. Foremost, lack of alertness is associated with an increased likelihood of errors and mistakes – both of which could lead to death.  To avoid fatal mistakes as a result of drug ingestion, troops are required to avoid benzos like clonazepam.  Should a troop test positive for clonazepam, he/she may be delisted.

How to get Klonopin out of your system

When most people stop taking a drug like Klonopin, their goal is to detoxify as fast as possible.  They may start exercising more, drinking a lot of water, eating healthier, and taking supplements – all of which may provide benefit.  Assuming you want to expedite the excretion of Klonopin, you may want to discuss some of the suggestions below with a medical professional.

  1. Stop taking it: If you want to ensure that Klonopin leaves your body as fast as possible, it’s necessary to fully discontinue. The discontinuation process is not easy, and should always be done under medical supervision. Realize that in order to completely excrete the drug, you’ll need to stay off of it for awhile.  The sooner you cease usage, the quicker it’ll be out of your system.
  2. Burn body fat: It is necessary to acknowledge that Klonopin is highly lipophilic, meaning it binds to fat stores and is distributed throughout bodily tissue. In these tissues it may accumulate, sometimes to a significant extent in long-term users. Doing exercises to efficiently burn body fat should theoretically expedite the elimination of clonazepam from fat stores – thereby facilitating quicker excretion.
  3. Activated charcoal: A supplement you may want to consider taking for the purpose of systemic detoxification is that of activated charcoal. Even if your final dose of clonazepam has been absorbed and distributed, any remnants or toxins associated with the drug that could be circulating throughout your body will likely get picked up by the charcoal. I believe that activated charcoal is among the best supplements for drug withdrawal.
  4. Acidification: Many speculate that a host of drugs are excreted more slowly and less efficiently when a body is alkalinized compared to when it is acidified. Acidification of your urinary pH and body may aid in the clearance rate and urinary excretion of clonazepam’s primary and secondary metabolites. To acidify your body, you can increase your intake of acidifying foods such as meats, cranberries, grains, etc.  Obviously you shouldn’t go overboard as to avoid inducing a state of acidosis.
  5. Hydration: It is known that a substantial portion of a clonazepam dose is excreted as metabolites within the urine. In addition to lowering urinary pH (via acidification), another trick is to stay hydrated. Overhydration is never smart because water can be toxic in excess.  However, staying optimally hydrated and drinking more water than usual can increase urinary flow rate.  Increases in urinary flow rate are associated with expedited drug excretion.

How long has Klonopin stayed in your system after stopping?

If you’ve stopped taking Klonopin, how long do you believe it stayed in your system before completely clearing?  Do you think there’s a chance that any of the drug or its metabolites may still be lingering within your bodily tissues or fat stores?  Share a comment below mentioning whether you think you cleared the drug quicker-than-average from your system or slower-than-average.

To help others get a better idea of your personal situation, discuss factors that may have had a substantial impact on Klonopin’s excretion from your body including: your age, the dosage you were taking, how long you had taken it, whether you have poor liver function, etc.  Understand that for most people, the drug will have fully been cleared from systemic circulation within 10 days of their final dose.  Only in extreme cases could the drug take around 14 days to fully excrete with its metabolites.

Related Posts:

{ 3 comments… add one }
  • Christopher June 8, 2016, 7:59 pm

    I took clonazepam since November 24th last year .25mg twice daily I recently went to .25mg for 1 week. Then half of that for 3 days, then stopped. Was that a good way to stop?

  • Shauna ward July 14, 2016, 12:04 am

    If I take two .5 clonazepam, how long will it take to be out of my system weighing 170 pounds and 5’8 and sweat a lot?

  • Southerner July 15, 2016, 11:24 am

    2 mg a day. Was recommended I decrease a pill by 1/4 every week until stopped. I’d rather get through pain quickly and be done with it. Not with this RX. I’m down to .25 mg a day with no note of withdrawals. On the other hand, any daily change (like forgetting to take 1 mg when taking 2mg a day) was disastrous. For me, it was impossible to sleep but I was very tired. And I have zero problems with sleeping cycles.

Leave a Comment