How Long Does Buspirone Stay In Your System For?

In our latest question and answer, the pharmacist discusses how long buspirone (Buspar) stays in your system for.


How long does buspirone stay in your system for?

Asked by Angelo2 On Oct 16, 2022

Answered by
Medical Content Reviewed By HelloPharmacist Staff

Published Oct 16, 2022
Last updated Apr 19, 2024

Key points

  • Buspirone has a short half-life, around 2 to 4 hours.
  • For most individuals, buspirone should be cleared from your system within 24 hours.
  • Taking buspirone with food may increase concentrations in the blood and prolong the elimination half-life.


Buspirone has a relatively short half-life (i.e. the time it takes for 50% of the drug to be metabolized) of around 2 to 4 hours. It is generally thought that it takes around 5 half-lives for a drug to be considered completely metabolized and eliminated from the body.

Therefore, you can expect buspirone to be completely metabolized after about 10-20 hours. In other words, for most individuals, buspirone should stay in your system for less than 24 hours (one day).

It should be noted that taking buspirone with food may prolong the effects of the drug as well as reduce the clearance of the drug from the body.

In fact, according to the prescribing information for buspirone, food can increase the maximum concentration of the drug in the blood by over 100%! Therefore, if you take buspirone with food, it may stay in your system slightly longer than usual.

Buspirone Information

Buspirone is an anti-anxiety medication but is neither structurally nor pharmacologically similar to other anti-anxiety medications like benzodiazepines (e.g. Xanax).

Buspirone is commonly used for mild to moderate cases of anxiety and typically does not cause physical dependence and doesn't significantly affect cognition or motor function. In addition, it isn't associated with withdrawal reactions (for most individuals).

While buspirone is generally considered a safer medication to use for symptoms of anxiety when compared to other classes of drugs, it does not confer immediate relief of anxiety and effects can take up to two weeks to occur. More commonly, it takes around 3 to 6 weeks for full effects to take place.

When taken by mouth, buspirone is quickly absorbed and the onset of action is generally 30 minutes to one hour. Once taken consistently, the effects of each dose last around 8 to 12 hours. Thus, for most individuals, it is commonly dosed two to three times daily to retain the effect. As discussed above, the half-life of buspirone is 2-4 hours.

Lastly, the exact mechanism of action of buspirone isn't well known but is thought to affect certain serotonin and dopamine receptors in the body.

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About the Pharmacist

Dr. Brian Staiger, PharmD

Dr. Brian has been practicing pharmacy for over 13 years and has wide-ranging experiences in many different areas of the profession. From retail, clinical, program development, and administrative responsibilities, he's your knowledgeable and go-to source for all your pharmacy and medication-related questions! Dr. Brian Staiger also has herbalist training and educational certificates in the field of medical ethnobotany. Feel free to send him an email at [email protected]! You can also connect with Dr. Brian Staiger on LinkedIn.

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