How Long Do Barbiturates Stay In One’s System?

Last Updated: June 24, 2020

Authored by Sharon Levy, MD, MPH

Reviewed by Michael Espelin APRN

People who are taking barbiturates, whether prescribed or not, may be concerned about passing a drug test. Barbiturate drug testing may be used by employers, medical professionals, corrections officers, and even concerned parents. Here is what users should know about how long medications of the barbiturate drug class remain in the system.

How Long Barbiturates Stay in the System

Barbiturate is a drug class, which encompasses numerous different medications. As such, there is no one answer to how long barbiturates stay in the system. If a person is using one of the common barbiturates, they should be able to look up the specifics on how long that exact medication remains in the system.

When looking at how long these drugs stay in the body, users should consider how long they are detectable through different samples. For example, how long barbiturates stay in the urine is different than how long they stay in the hair.

In general, most people testing for drug use will rely on the urine test. Given that barbiturates in urine last for quite a while, this means that anyone who is both using the drugs and likely to get tested for barbiturates will most likely turn up a positive result.

Barbiturate Half-Life

As with how long the drugs remain in the system, the half-life of barbiturates varies depending on the medication. Some barbiturates are very short-acting with similarly short half-lives while others are long-lasting and have longer half-lives. However, how long the effects of the drug last does not always line up with the barbiturate half-life. Below are half-lives for a few different barbiturates:

  • Brevital: Under five hour
  • Pentobarbital: 15 hours
  • Butabarbital: 100 hours
  • Primidone: 10 hours

It should be noted that much of what barbiturates treat can also be addressed with medications of other classes. If someone is worried about half-lives and drug testing, they should discuss benzodiazepines vs. barbiturates with their doctor.

patient talking to doctor

Barbiturates and Employment Drug Screenings

Employers will often require drug testing as part of the pre-employment process. Depending on the type of work, employees may be subject to random drug screenings throughout their time with the company. Anyone seeking employment or who has job with such a company should be concerned about passing the drug test.

Most companies that offer drug test use a simple 5-panel drug test. This looks for illegal drugs, amphetamines, and opiates, not barbiturates. Companies choose this test due to its affordability.

Should a company opt for a drug test that has seven panels or more, barbiturates will be tested for. Companies who choose these larger tests usually do so only if there is a great concern regarding intoxication on the job. For example, someone who operates a forklift might need to be tested for barbiturates and other medications that can cause drowsiness.

False Positives With Barbiturates

Someone can have a false positive for barbiturates. This can happen if there is an error with the test. However, there are also specific medications that can trigger false positives for barbiturates. Unfortunately, these medications are quite common.

Positive Test and No Prescription

If someone tests positive for barbiturates and does not have a prescription, the outcome will depend on who administered the test and whether or not it was a false positive.

What barbiturates are used for includes legitimate medical applications. As such, some employers might see a positive result and ignore it, assuming that taking them is not expected to impact performance on the job. However, if the department of corrections is doing the testing, the individual could end up being charged with a crime or having their parole revoked. If the family is administering the test, most likely, they will not turn the individual into the police but seek help in stopping use and getting clean.

If the positive test is a false positive, the person will need to contest the results and demand a more accurate form of testing.

young woman talking to a police officer

Factors That Impact How Long Barbiturates Remain in the System

While there are general guidelines for how long barbiturate medications stay in the system, many factors can alter that length. Some factors can allow users to pass a barbiturate drug test sooner, while others may mean the medication is detectable for longer. Some factors impacting the length of time barbiturates remain in the system include:

  • The type of barbiturate taken
  • The dose taken
  • How long the drug had been used
  • The age, weight, and gender of the user
  • The metabolism of the user
  • Any problems with the internal organs that make processing the medication harder
  • Other medications being taken at the same time
  • Alcohol consumption and illicit drug use

As such, no one can know with certainty how long their use will remain detectable.

How to Eliminate Barbiturates Faster

There is no surefire way to speed up the elimination of barbiturates to ensure someone can pass a barbiturate drug test. Once someone stops their use, they can expect to experience barbiturate withdrawal and should undergo detoxification. Things, like eating well, drinking lots of water, exercising, and getting the right amount of sleep, can all help speed up the detoxification process. However, they do not guarantee that someone will pass the drug test.

If someone is using barbiturates habitually, whether they are prescribed or not, they need to seek addiction treatment help with stopping them. Sudden cessation of barbiturates can trigger dangerous withdrawal. Drug rehabilitation centers have the expertise required to ensure users can get clean safely.

Page Sources

  1. Fritch D, Blum K, Nonnemacher S, Kardos K, Buchhalter AR, Cone EJ. Barbiturate detection in oral fluid, plasma, and urine. Ther Drug Monit. 2011 Feb;33(1):72-9.
  2. Drugs of Abuse Home Use Test. U.S. Food And Drug Administration.

Published on: August 12th, 2019

Updated on: June 24th, 2020

About Author

Sharon Levy, MD, MPH

After successful graduation from Boston University, MA, Sharon gained a Master’s degree in Public Health. Since then, Sharon devoted herself entirely to the medical niche. Sharon Levy is also a certified addiction recovery coach.

Medically Reviewed by

Michael Espelin APRN

8 years of nursing experience in wide variety of behavioral and addition settings that include adult inpatient and outpatient mental health services with substance use disorders, and geriatric long-term care and hospice care.  He has a particular interest in psychopharmacology, nutritional psychiatry, and alternative treatment options involving particular vitamins, dietary supplements, and administering auricular acupuncture.


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  • Kate
    Can a prescription for Sonata turn a (false/any) positive result for barbiturates?