How long does Klonopin stay in my system?

When starting Klonopin, you might have questions like how long does Klonopin stay in my system or how long does Klonopin last? We have the answers.


Ilchi Lee

Medically reviewed by

John Doe

May 28, 2021

Klonopin (clonazepam) is a well-known anxiety disorder medication that doctors and advanced practice nurses can prescribe to help us cope with a spectrum of anxiety disorders, like generalized anxiety disorder, social anxiety, and panic attacks. Klonopin also is used to help other conditions, such as sleep problems, seizures, and muscle spasms. When someone is prescribed Klonopin, just like with any medication, it’s essential to know the answers to our important questions.

Knowing the risks, benefits, side effects, and symptoms of possible withdrawal of Klonopin will help you determine if it's the best choice for your needs. You might be wondering how long Klonopin lasts, or how long it stays in your system, so you can know if it will show up on a drug or urine test. Understanding Klonopin better can improve your experience taking it.

Here’s our guide for what you need to know about Klonopin, including:

  • The basics of Klonopin
  • How long Klonopin stays in your system
  • Side effects of taking Klonopin
  • Best practices for taking Klonopin
  • Withdrawal management for Klonopin
  • Klonopin and addiction

This is intended for medical informational purposes only. Please consult with your doctor before switching medication.

Klonopin 101

Klonopin is the brand name for clonazepam. It is a prescription-only medication that comes in tablet or liquid form, taken orally. The dosage depends on our needs and personal factors, including our age and weight. The amount typically varies from 0.25-1 mg/per dose; your prescriber may prescribe 2-3 doses/day. Klonopin falls into the benzodiazepine (benzos) category of medications, which includes Xanax, Ativan, and Valium.

One of Klonopin’s main uses is to help with mental health concerns like anxiety, including GAD (generalized anxiety disorder), panic disorders, and social anxiety. It can also help with conditions created or affected by anxiety-related insomnia. As a benzodiazepine, Klonopin enhances the natural brain chemical GABA (gamma-aminobutyric acid), which calms down the central nervous system. This, in turn, helps lessen our anxiety.

People taking Klonopin for anxiety often report feeling immediate relief within hours or days after intake. Those improvements can mean feeling a sense of calm and improved sleep quality — which can be a relief for those of us struggling.

Doctors also prescribe Klonopin for conditions such as seizures, restless leg syndrome, and muscle spasms. For those with seizure disorders, Klonopin can help with certain types of epilepsy like Lennox-Gastaut syndrome and myoclonic absence seizures. When using it for this purpose, the medication can take a few days for noticeable improvements.

Klonopin is prescribed for various conditions.

There are certain medical conditions that Klonopin can negatively affect or worsen. Take note if you have specific conditions, including narrow-angle glaucoma, certain blood disorders (like porphyria), liver or kidney disease, depression, sleep apnea, or if you’re prone to addiction. Klonopin can also cause allergic reactions in some people, so verify it is not a medication that will worsen your allergies.

How long does Klonopin last?

Klonopin has a long half-life (the half-life of a drug is the time it takes for its peak blood level to fall by 50) at 30-40 hours, and its effects last 8-12 hours, with peak levels around 4 hours. It can stay in our bodies for a few days or up to 2 weeks. Other factors that influence the period of time that Klonopin and its metabolites (other active agents produced as the body breaks down a medication, including 7-aminoclonazepam) remain in our bodies include how long a person is taking it (duration of use), our age and weight, and our overall health.

How fast our bodies process Klonopin depends on our metabolisms. A younger person might have a faster metabolism than an older person, for example. Healthy organ function can speed up the process; a higher body mass index (BMI) can slow it down because Klonopin is soluble in our fat cells. That means the drug’s metabolites may attach to fat cells, thereby staying in our body longer.

If you’re wondering how long Klonopin stays in your system after one use versus after long-term usage, it depends. The longer we take the medication, the longer it will stay in our body, with a range from 4-14 days.  


Side effects of Klonopin

When you’re taking any medication, it’s important to be aware how your body may react. Some reported side effects include drowsiness, dizziness, lightheadedness, depression, poor coordination, muscle aches, and muscle weakness. Other side effects might be interrupted sleep, lack of concentration, or blurred vision.

Klonopin also can cause more serious side effects. Seek immediate medical support or emergency services if you notice slowed breathing, shortness of breath, hallucinations, or if you’re having suicidal thoughts.

Check with your doctor for any discomfort with Klonopin’s side effects so you can learn how best to manage/minimize your side effects. You also can consult one of the experts at Minded, available through our 24/7 clinical support email at or our helpline at 909-442-0618.

Best practices for taking Klonopin

Although your dosage and frequency of use will vary based on your doctor’s recommendation, it’s essential that you take the medication around the same time every day. Klonopin can be taken with or without food, depending on your preference. The most critical factor is to take your dosage consistently as prescribed. Any variation in how you take it can disrupt its effectiveness.

Due to its sedative effect, Klonopin can cause drowsiness, dizziness, or lack of coordination. It’s important to be mindful that we may not be as alert as usual, which means we should avoid activities like operating heavy machinery or driving a car if we experience these side effects.

What happens if you miss a dose of Klonopin

If you miss a dose of Klonopin, take it as soon as you remember, unless it’s near the time of your next dose. In that case, just wait until that next dose. If you forget to take a dose, you might notice some withdrawal symptoms. Don’t take 2 doses to make up for the forgotten dose. Taking 2 doses will increase how long Klonopin stays in your system and can cause a greater chance of overdose.

Stay on top of your dosage and use of Klonopin by getting your prescription through Minded, which sends reminders when it’s time to renew your medication.

Other substance use with Klonopin

Don’t take alcohol and other sedating drugs with Klonopin. Period. Alcohol or marijuana can increase Klonopin’s side effects and can put us in a deep sleep, which can cause breathing problems. Taking Klonopin with substances, such as opioid pain medications (e.g., Oxycontin, Vicodin, and codeine, as well as methadone) may be a dangerous combination. Combining Klonopin with any of these drugs (alcohol, cannabis, and opioids) can make it more addictive to you.

Also, because of Klonopin’s relaxing quality, take precautions with caffeinated beverages such as coffee or soda, as they might negate the medication’s calming effects.

If you’re taking any other medication, check to see how it interacts with Klonopin.

Pregnancy and Klonopin

There are risks associated with taking Klonopin while pregnant, so it is not usually suggested. But if you depend on Klonopin to manage your anxiety, panic or seizures, and want to continue it, be sure to discuss with your prescribing clinician or obstetrician about how to best proceed.  

Be sure to inform your primary care doctor as soon as you can about the Klonopin you are taking because of its potential effects on pregnancy, fertility, and breastfeeding. There have not been sufficient studies done regarding human fertility and Klonopin, but a study in rats did show a lower pregnancy rate in those being given this medication.

Klonopin passes into breast milk. If you and your doctor decide to continue this medication, be sure to pay extra attention to any unexpected changes in your baby’s behavior, like seeming more tired than usual or slow breathing.

Since Klonopin does have a long half-life and stays in our body for a few days, it is often recommended for someone who is breastfeeding to take a lower dosage or choose another medication with a shorter half-life.

Ending Klonopin use and withdrawal symptoms

It can be difficult to know when a medication isn’t the right choice for you. If you’re not sure if your Klonopin prescription is working, Minded can help you consider that question and adjust the dose or timing of taking this medication. Our care team will work with you in figuring out the best course of action, whether your dosage is too high, too low, or if you may benefit from another medication.

When reducing the dose of Klonopin, there may be risks of withdrawal, so you can benefit from speaking with your doctor or Minded’s clinical professionals in order to best avoid withdrawal complications. If you stop taking Klonopin suddenly, you may experience headaches, fatigue, seizures, tremors, sweating, nausea, or diarrhea. You also could experience psychological withdrawal symptoms, including mood swings, confusion, depression, anxiety, memory lapses, and hallucinations. There are tapering off methods to better ensure a safe withdrawal, which Minded can help you understand.

Keep track of your dosage, so you know how long Klonopin will stay in your unique body systems. Knowing how long Klonopin lasts will help you and your prescriber understand the amount of time it will take to detox from it. Acute withdrawal generally reaches peak levels after approximately 14 days from your last dose, though it may last from a week to over a month.

Drug testing and Klonopin

Klonopin will appear in a drug screening that tests for benzodiazepines. Some employers have started drug screening due to prescription drug abuse. So, how long does Klonopin stay in your system that a drug test can identify?

Klonopin is detectible for various amounts of time depending on which test we take, such as:

  • Urine drug test: Up to 1 month
  • Hair test: 1-3 months
  • Saliva test: 5-6 days
  • Blood test: Up to several days

These detection times can also help you understand how long Klonopin stays in your system after you stop taking it. If you know you have an upcoming screening, plan accordingly with your prescriber as to your use of Klonopin.

Addiction and Klonopin

There is not a high risk of addiction to Klonopin if taken for a short time, such as 2-4 weeks. However, a person may develop dependence — which means tolerance (needing a higher dose to achieve its effects) and/or withdrawal (a variety of symptoms if the dose is suddenly reduced) — after 2 weeks or more of daily doses. The longer we take Klonopin, the higher the chance of developing a Klonopin addiction. We can avoid the risk of addiction by taking it as prescribed and letting our doctor know if we feel we are becoming dependent on this medication.

Signs of a Klonopin overdose

Lack of coordination, trouble speaking, excessive sleepiness, irregular or slowed heartbeat, delayed reflexes, confusion, coma, and delirium are some signs you might have taken too much Klonopin. If you’re concerned about a potential overdose, contact medical help or 911 for emergency services.

Be cautious of situations that could increase your chance of overdosing on Klonopin. Don’t mix any substances like alcohol or sedating drugs with your Klonopin because the combination could heighten Klonopin’s effects. And as we said earlier, do not double up on Klonopin dosages if you missed one.

Final thoughts: How long does Klonopin last? + Other Klonopin answers

Klonopin can be very helpful in taming your anxiety and allowing you to have a fuller, more productive life. Its side effects include drowsiness and muscle aches. How long Klonopin lasts and those symptoms depend on how long we’ve been taking it, our age, weight, and our overall health.

Klonopin appears on drug screenings, including saliva or hair follicle tests. Knowing how long Klonopin stays in your system can help you determine if you, and your prescriber, should decide to continue taking it.

There’s a high chance of becoming addicted to Klonopin if taken for an extended period of time. Be sure to know the symptoms of an overdose. If you and your prescriber think you are becoming addicted, seek out the help of a clinical program, such as outpatient rehab or inpatient addiction treatment center.

Klonopin can help us improve our physical health by reducing the stress anxiety produces on a number of our body’s organs. By knowing answers to your questions, you can feel more confident about your Klonopin use.

Do you want to renew your prescription medication online? Try Minded for a quick, easy solution today. Contact us to learn more.

Mental health


Stay mindful with Minded

Get mental health and wellness resources delivered right in
your inbox every month.

Thank you! Your submission has been received!
Oops! Something went wrong while submitting the form.
Get started