How long do benzos stay in your system?

Benzodiazepines (Benzos) can stay in your system for weeks to months after last dose. Learn more about short and long acting benzos, their half lives and detection times here.

minute read
Reviewed by: Dr. Dili Gonzalez, M.D. Dr. Juan Goecke, M.D.

ARTICLE OVERVIEW: Benzodiazepines can be detected up to 30 days in urine although chronic use (1+ years) can be detected 4–6 weeks after last dose in urine. Benzos can also be detected in serum and plasma for 12 hours to 2 days after last dose.


Taking Benzos

Benzodiazepines, or “Benzos”, are one of the most powerful tranquilizer sedatives prescribed by doctors. As a central nervous system depressant, benzodiazepine can be highly effective. However, benzos vary in terms of uses, active times and addictive qualities. When taken recreationally, people use these meds for sedative effect, or to enhance the effects of alcohol or opioids…but also increase addictive potential.

Medically, benzodiazepines are prescribed to induce sleep, relieve anxiety, to sedate, treat muscle spasms and prevent seizures. Benzos can also be prescribed during alcohol withdrawal, or used to treat anxiety related disorders of the gastrointestinal tract. They should only be prescribed for short periods of time.

Benzodiazepines are usually prescribed and taken orally, but some people use benzos without a prescription from a doctor. This is illegal and can be very dangerous. Some use intravenous injection after preparing a solution from crushed tablets. Commercially available liquid forms can also be injected, and gel forms can be rectally administered.

The list below shows some of the different generic and brand names of benzodiazepines:

  • Bromazepam: Lexotan.
  • Clonazepam: Rivotril.
  • Diazepam: Valium, Ducene, Antenex.
  • Flunitrazepam: Rohypnol, Hypnodorm.
  • Lorazepam: Ativan.
  • Nitrazepam: Mogadon, Alodorm.
  • Oxazepam: Serepax, Murelax, Alepam.
  • Temazepam: Euhypnos, Normison, Temaze.

Some slang names for benzos are rowies, serries, moggies, vals, V, normies, downers, tranks and sleepers.

Main Effects

The effects of benzodiazepines can be divided into immediate and long-term effects and may last from a few hours to a few days, depending on the dose and type of benzo you take.

The immediate effects can include that you:

  • Become confused or dizzy.
  • Cannot judge distances or movement properly.
  • Cannot remember things from just a short time ago.
  • Feel drowsy, sleepy or tired.
  • Feel really good.
  • Feel relaxed.
  • Have blurred or double vision.
  • Have mood swings.
  • Have no energy.
  • Slur your words or stutter.

If you use benzodiazepines often for a long time, you may:

  • Be cranky.
  • Be depressed.
  • Be hungrier and put on weight.
  • Experience fatigue or drowsiness.
  • Feel sick in the stomach.
  • Get skin rashes.
  • Have dreams that make you feel bad.
  • Have headaches.
  • Have menstrual problems if you are a woman.
  • Have no energy or interest in doing normal things.
  • Lose interest in sex, or your body will not work properly during sex.

Factors that Influence Metabolism

Not everyone reacts to benzos the same way. In fact, there are a number of factors that play into how these types of drugs effect you and how you metabolize them. For example, your current mood, past experience with benzodiazepines, and whether you use alone or with others, at home or at a party can also include outcomes.
Generally, benzodiazepine metabolism depends on:

  • How many tablets and what dose you take.
  • Route of administration.
  • Whether you use benzos on their own or with other drugs.
  • Your general health.
  • Your height and weight.

Peak Levels And Half-Life

Peak levels and drug half life of benzos depend upon the particular drug prescribed, dosage, interval between doses, and route of administration. Longer half-life benzodiazepines have a more sustained effect, although some may accumulate. In general, benzos can be divided into these three categories:

Ultra short acting benzos: The half-life of ultra short acting benzodiazepines is less than 5 hours. These drugs are essentially non-accumulating.

Short acting and intermediate benzos: This class of benzodiazepines have half-life values from 5-24 hours and can be dosed more frequently. Accumulation during multiple dosage is less extensive than with the long-acting group, and diminishes as the half-life becomes shorter.

Long acting benzos: Long acting benzodiazepines have half-life values usually exceeding 24 hours. Drugs in this category have long acting pharmacologically active metabolites, which accumulate extensively during multiple dosage.

Blood, Hair, And Urine Sample Tests

Testing cutoff concentrations for benzodiazepine are at 200 ng/ml. So how long do benzos stay in the body?

Blood: Benzos can be detected in serum and plasma for 12 hours to 2 days after last dose.

Hair: Hair samples are usually not used to detect benzodiazepines. While some popular medicines like diazepam may regularly be detected via this method, false negative results and variability in performance make this test less standard.

Urine: Benzodiazepines can be detected up to 30 days in urine although chronic use (1+ years) can be detected 4–6 weeks after last dose in urine.

You can find a full list of Drug Tests approved by the FDA here. [1]

Benzodiazepines are now part of most routine drug screening procedures. Most standard drug screens are usually unable to distinguish between different benzodiazepines. Since a number of benzodiazepines share common pathways of metabolism, it is not possible to test for the abuse of specific benzodiazepines such as diazepam or temazepam. It is also difficult for drug tests to detect ‘low’ dose benzodiazepine use.

Tolerance and Dependence

Anyone can develop a ‘tolerance’ to benzodiazepines. Tolerance means that you must take more of the drug to feel the same effects you used to have with smaller amounts or lower doses. This may happen very quickly with benzodiazepines.

Physical dependence occurs when you regularly take benzos for period of a few weeks or longer. In fact, most of the drugs in this class of medications should be prescribed for 6 weeks or less, due to the phenomenon of dependence. According to this 2015 article published in the Australian Prescriber [2]:

Any patient who has taken a benzodiazepine for longer than 3–4 weeks is likely to have withdrawal symptoms if the drug is ceased abruptly. The risk of inducing dependence can be reduced by issuing prescriptions limited to 1–2 weeks supply.

When you become drug-dependent, your brain has adapted to the psychoactive chemicals found in the benzodiazepine by compensation, in this cases, “speeding up” certain processes or functions. It does this to balance out the sedative, depressant effects of the strong benzo drug in your system. When you significantly lower dosage or quit altogether, it takes time for the brain to find homeostasis again. So, withdrawal symptoms occur.

However, benzo dependence is not limited to physical dependence. ‘Psychological dependence’ on benzodiazepines is also possible. When a benzo takes up a lot of your thoughts, emotions, and activities…you might be hooked on it. People who are psychologically dependent spend a lot of time thinking about using benzodiazepines, looking for them, using them, and getting over the effects of using them. You may also find it difficult to stop using or control how much you use. This kind of dependence, also known as addiction, can lead to a variety of health, money, legal, work and relationship problems.

Not all people who ever use benzodiazepines become dependent. But it is very easy to become dependent on benzodiazepines and it can happen within four weeks.


People who are dependent on benzodiazepines find it very hard to stop using them or cut down because of withdrawal symptoms. Withdrawal often involves “rebound” symptoms related to the original problem. So, if you were taking the meds to control anxiety, your anxiety can be amplified. Likewise for sleeping problems.
Still, suddenly stopping using benzodiazepines can be dangerous. You should get help and withdraw gradually if you have been using benzos regularly or using high doses of them. Tapering guidelines outlined by Dr. Heather Ashton are consider the go-to medical guidance for safely coming off these strong drugs. [3]

Symptoms of benzo withdrawal can include:

  • Being confused or depressed.
  • Convulsions.
  • Disturbed sleep.
  • Feeling nervous or tense.
  • Feeling afraid or thinking other people want to hurt you.
  • Feeling distant or not connected with other people or things.
  • Flu-like symptoms.
  • Heavier menstrual bleeding and breast pain in women.
  • Pain, stiffness or muscle aches or spasms.
  • Panicking and feeling anxious.
  • Shaking.
  • Sharpened or changed senses (e.g. Noises seem louder than usual).

Signs of a Problem

There is significant concern regarding overprescribing of benzodiazepines and the resultant harms. People who are benzodiazepine dependent or at risk because of misuse should be identified and appropriately assessed to determine their risk of harm.

You may have a problem if you present any of these characteristics:

  • Amnesia.
  • Appearance of dementia.
  • Benzodiazepine overdose.
  • Blurry vision.
  • Confusion.
  • Disturbing dreams.
  • Drowsiness.
  • Hostility.
  • Instability when walking or moving.
  • Irritability.
  • Judgment alteration.
  • Lack of coordination.
  • Reduced inhibition.

Furthermore, these medicines can be addictive. Since many benzodiazepine addictions start out as prescriptions, it can be challenging to notice when a person becomes addicted. Once a person has become addicted to benzodiazepines, they may appear detached and apathetic. They may begin removing themselves from normal family and social activities and lose interest in hobbies and maintaining relationships.

The main signs of benzodiazepine addiction include:

  1. Continued use, despite harm to health, work, or relationships.
  2. Feeling that you cannot function without the medicine.
  3. Trying to quit but being unable to stop.
  4. Using benzos to get high.

Prescribing interventions, substitution, psychotherapies and pharmacotherapies all contribute to the management of benzodiazepine dependence.

Risks of Misuse

The way a person uses benzodiazepines can also cause some problems. If you take a very high dose of benzodiazepines alone or with other drugs, you can depress the respiratory system, go into a coma or die. Injecting benzodiazepines that are intended to be swallowed in tablet/capsule form can also cause severe damage to veins, leading to loss of limbs from poor circulation, organ damage or stroke. Injecting benzodiazepines with used or dirty injecting equipment makes you more likely to get infected with HIV, hepatitis B or C, get blood poisoning and skin abscesses.

NOTE HERE: To minimize possible harm, avoid injecting benzos. If you do, DO NOT SHARE fits (needles and syringes), spoons, water, filters, alcohol swabs, or tourniquets.

Benzos and Addiction

Do you have problems with Benzodiazepines? If you think that you have a problem (with any chemical or drug), you probably do. Ask yourself, why you are taking it? And you will have an answer. We understand some benzodiazepines are more addictive than others and the problems they can cause.

You are not alone. In fact, once you are ready to face potential addiction to drugs, help is available. If you think that you are addicted to benzos, please email us or write us a comment below. We would love to hear from you and are here to help you get treatment.

Reference Sources: [1] FDA: Drugs Of Abuse Test
[2] NCBI: Management Of Benzodiazepine Misuse And Dependence
[3] New Castle University: Benzodiazepines: How They Work And How To Withdraw
FDA: Drug Safety
NIDA: Well-Known Mechanism Underlies Benzodiazepines’ Addictive Properties
NIH: Detection OF Benzodiazepines AND Z-Drugs IN Hair Using AN Uhplc-Ms/Ms Validated Method: Application TO Workplace Drug Testing
SAMHSA: FDA Regulation Of Drugs Of Abuse Tests
STATE OF NJ: Benzodiazepine Addiction Help And Treatment In New Jersey
About the author
Lee Weber is a published author, medical writer, and woman in long-term recovery from addiction. Her latest book, The Definitive Guide to Addiction Interventions is set to reach university bookstores in early 2019.
Medical Reviewers
Dr. Dili Gonzalez, M.D. is a general surgeon practicing women's focused medici...
Dr. Goecke is a medical doctor and general surgeon with personal experience of...

All of the information on this page has been reviewed and verified by a licensed medical professional.

I am ready to call
i Who Answers?