How Long Do Benzodiazepines Stay in Your System?

Last Updated: September 4, 2019
The benzodiazepines are a large class of drugs that are primarily used in the treatment of anxiety that is clinically severe as a result of a psychiatric disorder or neurological condition, but they are also used for numerous other purposes. Benzodiazepines include familiar drugs like Valium (diazepam) and Xanax (alprazolam), and drugs that are not so familiar like Restoril (temazapam).

How Benzos Work

Pill bottle on its side with controlled substance pills falling out of the bottle with a white background.

All of the benzodiazepines are believed to have a similar mechanism of action although the exact mechanism has never been fully described. They are believed to work by affecting a specific brain chemical, a neurotransmitter known as gamma-aminobutyric acid, or GABA. Neurotransmitters are the messengers for the neurons in the brain and spinal cord, and responsible in one way or another for the vast majority of human behavior. GABA is an inhibitory neurotransmitter, meaning that it suppresses the functioning of the neurons in the brain and spinal cord.

Because many of the conditions that benzodiazepines address are believed to be associated with rapid-firing rates of neurons, such as seizures or anxiety, these medications offer viable medical treatments for some of these conditions. Even though they are all similar, the benzodiazepines will differ in:

  • How fast they take effect (rate of onset of action)
  • How long their effects last (duration of action)
  • Their potency (how much of the drug can cause an effect)
  • Their tendency to remain in the system or build up in the body

There are numerous uses for benzodiazepines that include to treat anxiety, to reduce seizure activity, and to help individuals sleep. Benzodiazepines can also be used for:

  • Anesthesia or to induce sedation prior to surgery or some diagnostic procedure
  • Relaxation
  • Nausea and vomiting, in some cases
  • Withdrawal symptoms from alcohol and some other drugs

There are numerous drugs in the benzodiazepine class. In general, benzodiazepines are interchangeable in their use, but some are more commonly used for specific types of conditions.

  • Anxiety disorders are most commonly addressed by Xanax, Librium (chlordiazepoxide), Ativan (lorazepam), and Valium.
  • Seizure disorders are most often addressed by Ativan, Valium, Klonopin (clonazepam), and Onfi (clobazam).
  • The benzodiazepines that are commonly used as anesthesia include Valium, Ativan, and Versad (midazolam).
  • Benzodiazepines that are commonly used to address insomnia or issues with sleeping are Restoril, Halcion (triazolam), and Prosom (estazolam).
  • Withdrawal from alcohol is most often treated with Valium or Librium.
  • Valium and Xanax may also be used as muscle relaxants in some cases.

Benzodiazepines were hoped to be used as replacements for another class of drugs, the barbiturates, which was commonly used in the treatment of anxiety and seizures. Barbiturate abuse became a significant societal concern, and benzodiazepines were believed to have a lower potential for abuse than barbiturates.

However, all benzodiazepines are controlled substances (most often classified by the Drug Enforcement Administration as Schedule IV controlled substances), and all benzodiazepines have the potential for abuse. The Substance Abuse and Mental Health Services Administration (SAMHSA) reports that in 2016:

  • Over 30.5 million Americans over the age of 12 used some form of benzodiazepine.
  • Approximately 5.6 million individuals admitted to at least one misuse of a benzodiazepine.
  • About 18.4 million individuals use alprazolam (Xanax), and of this group, about 4.3 million reported misusing the drug at least once.
  • About 7 million individuals used diazepam (Valium), and nearly 1 million reported misusing it at least once.
  • About 7.3 million individuals reported using lorazepam (Ativan), and about 786,000 of these individuals reported misusing it at least once.

SAMHSA and other organizations report that benzodiazepines are not often primary drugs of abuse and are most often abused in conjunction with other drugs. The most common drugs used and abused with benzodiazepines include other benzodiazepines, opiates, alcohol, cannabis, and some stimulants.

How Long Do Benzodiazepines Remain in the Body?

The answer to this question is not as simple as it may seem. Different benzodiazepines have different durations of action and different half-lives even though they all are relatively similar. This means that some benzodiazepines will be eliminated from the body relatively quickly, whereas others may remain in the body for a longer period of time.

  • Valium is a long-acting benzodiazepine and may be detectable in a person’s system for up to 10 days after using it.
  • Xanax, Ativan, Restoril, Librium, and Klonopin have intermediate durations of action and may be detectable in the system for five days.
  • Halcion is a short duration and may be detectable the system for up to two days.

The above figures are general estimations, and there will be quite a bit of individual variability regarding the length of time any particular benzodiazepine remains in a person’s system. The type of detection test will also result in different detection times with blood testing having the shortest window of detection followed by urinalysis with an intermediate duration of detectability, and then hair follicle testing with the longest window of detectability.

Again, the length of time any benzodiazepine remains in the system is dependent upon its duration of action. For instance, in one study, Valium was detected in an individual’s system for a period of seven days, whereas Xanax was only detectable in the person’s system for 2.5 days.

Long-acting benzodiazepines include Librium and Valium. Intermediate-acting benzodiazepines include Xanax, Ativan, Klonopin, and Restoril. Short-acting benzodiazepines include Halcion.

Certain metabolites that are produced when benzodiazepines are broken down in the body may be detectable in drug tests for significantly longer periods of time than the drug itself. This complicates the situation.

More on How Long Drugs in the Body

Influencing Factors

glass of alcohol and pills on table

It should be noted that factors other than the properties of the drug itself can influence how long the drug remains in a person’s system. Since benzodiazepines are commonly abused with other drugs, this may result in the benzodiazepine being metabolized more slowly.

The classic example is taking benzodiazepines with alcohol. The liver, which is the organ that is primarily responsible for metabolizing most drugs, gives priority to metabolizing alcohol over all other substances. Alcohol is metabolized first at the rate of about one ounce of pure alcohol per hour. When the alcohol is metabolized, then the liver begins metabolizing other substances. Thus, individuals who mix different drugs may retain the drugs in their system for longer than they would normally.

There are other factors that can affect the length of time drugs remain in the system.

  • There are individual variations in liver functioning and metabolism.
  • Age is always a significant factor because older individuals tend to metabolize drugs more slowly than younger individuals.
  • Body size, particularly weight, can influence how fast the drug is metabolized. In most cases, drugs are metabolized more quickly in heavier people, although this is not always the case.
  • Hydration may influence the rate at which a drug is eliminated from the body. Since the majority of drugs are primarily eliminated through urine, individuals who urinate more frequently may eliminate certain drugs quicker.
  • A person’s general health would obviously affect their metabolism and the rate at which drugs remain in the system.
Last Updated on September 4, 2019
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