Buspirone Half-Life: Can It Influence Screening Results?

Last Updated: July 10, 2020

Authored by Isaak Stotts, LP

There is a myth that taking Buspar before a drug test may skew the results. Though Buspirone leaves the system quite rapidly, its metabolites can be found in different body systems for a certain period of time. Does Buspar show up on a drug test? If yes, how long does Buspar stay in one’s urine? What is the half-life of Buspirone? Follow the article to find out the answers to these questions.

Buspirone On Drug Test

Naturally, one might wonder if there are special drug tests for Buspirone and its metabolites. The answer is – no. First of all, this medicine is not a controlled one. Secondly, it is not included in standard drug tests (5-12 panel tests). At the same, there is a concern that Buspirone may show up as benzos. As of now, there is no evidence that would support this claim.

Half-Life Of Buspar

On the average, the half-life and full elimination time of a single Buspirone 5mg to 40mg dose is 2 to 3 hours. However, several factors can influence the half-life of Buspirone.
Laboratory Worker Notes Test Results
Buspirone is metabolized by the liver and excreted by the kidneys, so any damage to either of these organs can prolong the half-life (the extent depends on the individual case). This is why Buspirone is not recommended for patients with impaired renal or hepatic function. It has been discovered that people living with these health conditions may experience increased plasma levels and a prolonged half-life of Buspirone in the body.

Additionally, the dosage used won’t affect how long Buspar stays in the system. People that overdose in a bid to get high won’t experience a noticeable increase half-life of the drug. For instance, a Buspirone 15mg high will result in milder drowsiness than from a 60 mg tablet but the half-life of the drug remains the same.

Additionally, there is no evidence that would state that Buspar interactions affect half-life. So, using Buspar and Prozac together, for instance,  won’t result in an extended half-life.

The Detection Window For Buspirone

There are a number of drug screening methods that are used for drug tests. Some of the most common options are the saliva test, the blood test, and the urine test – the sample types required for each are fairly obvious. When using Buspirone, one needs to be wary of the elimination time of the medication in relation to each type of drug test.

Vanspar And Urine Test

Does Buspirone show up in a urine test? No, it doesn’t, because these tests are not even aimed at identifying Buspar presence. Yet this doesn’t mean that the medicine can’t be found in urine samples. According to a study carried out by the US Food and Drug Administration, it takes up to 24 hours for 29% to 62% of Buspirone to be eliminated in urine as metabolites.
The Equipment For The Drug Screenings

Buspirone Stay In Saliva And Blood Samples

With its relatively short half-life, Buspar only leaves the blood and saliva within 18 to 24 hours after use. Contrary to the case with urine screenings, there is no empirical evidence to show that Buspar affects blood and saliva drug screenings in any specific way.

False-Positive Results On Buspar

The similarity between Buspar and benzos was briefly mentioned earlier. However, will Buspar test positive for benzos on a drug test? No, it won’t because Buspar is anti-anxiety medicine and not a benzodiazepine. Moreover, Buspar should not show up on a drug test at all because it is not a controlled substance. It can only affect the results of clinical urine screenings. In fact, the FDA indicated a false laboratory result where Buspar was incorrectly read as metanephrine during a routine assay testing for pheochromocytoma.

Weaning Off Buspar

One may not have the luxury of stopping Buspar up to 48 hours before a drug test. This may lead to thoughts about weaning off Buspar to flush it out of the system manually through unapproved methods. It is important to stress the fact that this action is not recommended and it is best to wait for the full elimination of the med.

Keeping The Drug Record Clean

With a relatively short half-life, Buspirone is a medication that won’t cause any trouble on the screenings. Besides, the possibility of the false-positive on Buspar is close to zero. However, Buspar addictive properties are very weak, yet the probability of medication abuse is still present. Buspar common side effects like relaxation and sedation are primary reasons for abuse. There are a variety of ways one can abuse Vanspar. In this case, routine tests won’t help uncover the presence of addiction.

If a close or a loved one is suspected of abusing the Vanspar, it is the time to contact a local drug rehabilitation facility. There, a patient will undergo either a long-term or short-term drug rehabilitation program. These programs are usually multi-staged and include not only the initial detox but also physical and psychological treatment. The idea of such a treatment is to identify the initial cause of the problem, resolve the issue, and provide supportive therapy afterward.

Page Sources

  1. Mahmood I, Sahajwalla C. Clinical pharmacokinetics and pharmacodynamics of buspirone, an anxiolytic drug. Clin Pharmacokinet. 1999;36(4):277-287. https://pubmed.ncbi.nlm.nih.gov/10320950/
  2. Gammans RE, Mayol RF, Mackenthun AV, Sokya LF. The relationship between buspirone bioavailability and dose in healthy subjects. Biopharm Drug Dispos. 1985;6(2):139-145. https://pubmed.ncbi.nlm.nih.gov/2860931/

Published on: July 10th, 2020

Updated on: July 10th, 2020

About Author

Isaak Stotts, LP

Isaak Stotts is an in-house medical writer in AddictionResource. Isaak learned addiction psychology at Aspen University and got a Master's Degree in Arts in Psychology and Addiction Counseling. After graduation, he became a substance abuse counselor, providing individual, group, and family counseling for those who strive to achieve and maintain sobriety and recovery goals.


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