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Jun 28, 2021
4 min read

Buspirone (Buspar): dosage, uses, side effects

Buspirone (brand name Buspar) treats generalized anxiety disorder (GAD) and short-term symptoms of anxiety. It works by mimicking serotonin, a naturally occurring substance in our brains that affects how our brain cells communicate. Common side effects of buspirone include dizziness, drowsiness, and nausea.

Reviewed by Chimene Richa, MD

Written by Michael Martin

Disclaimer

If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.

Anxiety is more than just worrying about work or home stresses—it is an excessive worry that can make it difficult to function. Fortunately, there are treatments available. Buspirone, brand name Buspar, is one of the medication options that may help. 

But before you start buspirone for anxiety, you should know more about it. Read on to learn about Buspar’s uses, side effects, and more.

What is buspirone (Buspar)?

Buspirone (brand name Buspar; see Important Safety Information) is used to treat generalized anxiety disorder and short-term anxiety. It’s part of a class of anxiety medications known as anxiolytics. They work by changing the levels of certain chemicals in the brain, called neurotransmitters (Wilson, 2020).

Buspirone is a serotonin receptor agonist, which means that Buspar binds to the serotonin receptor in the brain, stimulating that receptor. Scientists know that increasing serotonin in the brain seems to improve symptoms of conditions like anxiety. Buspirone may also affect dopamine receptors—dopamine is another neurotransmitter involved in mental health (Wilson, 2020).

Unlike benzodiazepines (like diazepam and alprazolam) and barbiturates, buspirone is not habit-forming. It has a low risk of dependence or abuse, making it more helpful in treating anxiety. However, buspirone does not work immediately. It begins to kick in after two to four weeks of use (Wilson, 2020).

Today, buspirone is only available as a generic medication—Buspar has been discontinued.

Buspirone uses

The U.S. Food and Drug Administration (FDA) approves buspirone to treat (UptoDate, n.d.):

  • Generalized anxiety disorder (GAD): People with GAD feel excessive anxiety; they may worry about anything and everything, including everyday things like family, relationships, work, etc. This anxiety can interfere with work, school, social interactions, and other aspects of daily life. Taking Buspar for anxiety may help.
  • Short-term relief of the symptoms of anxiety (not for normal stresses of everyday life) 

Clinical trials have shown that buspirone is as effective as benzodiazepines (like Xanax, Valium, etc.) for generalized anxiety disorder. However, because buspirone can take two to four weeks to work, it is not used for episodes of acute anxiety (Wilson, 2020). 

Drugs are sometimes used “off-label,” which means that the drug is being used for a condition that it is not FDA-approved to treat. One off-label use of buspirone includes treating depression when used along with another antidepressant.

Buspirone also helps reduce the sexual side effects of SSRI (selective serotonin reuptake inhibitor) medications. SSRIs are drugs commonly used to treat depression (Wilson, 2020). 

Buspirone side effects

Like many medications, buspirone can cause adverse effects. Some of the common side effects of buspirone include (UptoDate, n.d.):  

  • Dizziness
  • Nausea
  • Headache
  • Nervousness
  • Lightheadedness
  • Excitement

There is also the potential for serious side effects when taking buspirone. These include (UptoDate, n.d.):

  • Movement disorders like akathisia or dyskinesia (inability to sit still or control body movements)
  • CNS (central nervous system) depression, which happens when the body’s neurological functions slow down. Because of this possible side effect, you should not drive or operate heavy machinery while using this medication. 

If you experience any of these possible side effects while taking buspirone, seek medical advice.

Buspirone dosage

Buspirone hydrochloride tablets are available in 5 mg, 7.5 mg, 10 mg, 15 mg, and 30 mg tablets. The recommended starting dose for generalized anxiety disorder is 10–15 mg daily, divided into two doses of 7.5 mg or three doses of 5 mg. The maximum daily dosage is 60 mg a day (Wilson, 2020). 

It doesn’t matter if you take buspirone with or without food, but you should be consistent and take it around the same time each day. Avoid taking this drug with large amounts of grapefruit juice. If you miss a dose of buspirone, take it as soon as you remember. But you should skip the missed dose if it’s almost time for your next dose. Never take two doses at one time (MedLinePlus, 2019).

Buspirone warnings

You should not take buspirone if you are allergic to it, especially if you have a severe allergic reaction like hives, swelling, or trouble breathing.

People with severe liver disease or reduced kidney function should not use buspirone because the liver metabolizes it and the kidneys excrete it (UptoDate, n.d.).

Buspirone is a pregnancy Category B drug, meaning there is not enough data to know whether buspirone is safe to take during pregnancy or if the medication is expressed in breast milk. Buspirone should be only taken by pregnant or breastfeeding people when necessary and after consulting with a healthcare provider.

Alcohol can intensify the drowsiness and impairment that buspirone might cause. You should not drink alcohol while taking buspirone (Wilson, 2020).   

Some studies have found that drinking grapefruit juice while taking buspirone can increase drug levels in the blood. Therefore, you should avoid drinking large amounts of grapefruit juice while taking buspirone (UptoDate, n.d.). 

Buspirone drug interactions

Buspirone can cause dangerous drug interactions—be sure to let your healthcare provider know about any other medications (prescription, over-the-counter, herbal products, etc.) you’re taking. 

You should not use buspirone with medications known as MAOIs (monoamine oxidase inhibitors) as it can lead to serotonin syndrome, a potentially life-threatening condition. Serotonin syndrome symptoms include confusion or agitation, muscle twitching or rigidity, increased heart rate, elevated body temperature, nausea/vomiting, high blood pressure, sweating, and dilated pupils (Simon, 2021). 

Don’t take buspirone within 14 days of taking an MAOI, including (UptoDate, n.d.):

  • Isocarboxazid 
  • Linezolid
  • Methylene blue injection
  • Phenelzine
  • Rasagiline
  • Selegiline
  • Tranylcypromine

MAOIs are not the only medications that may cause a serotonin syndrome drug interaction. Taking antidepressants like SSRIs (e.g.fluoxetine; see Important Safety Information), SNRIs (serotonin-norepinephrine reuptake inhibitors), trazodone, or any other drug that increases serotonin levels can lead to serotonin syndrome (Simon, 2021).

Taking buspirone with medications that block or stimulate liver enzyme CYP3A4 may change the levels of buspirone in your blood because this enzyme breaks down the drug—your healthcare provider may need to adjust your dosage if you’re taking these medications. 

Medicines that affect CYP3A4 include diltiazem, verapamil, erythromycin, itraconazole, nefazodone, rifampin, ketoconazole, ritonavir, dexamethasone, and certain seizure medicines (DailyMed, 2019). 

This does not include all potential drug interactions, and others may exist. Talk to your healthcare professional or pharmacist for more drug information. 

References

  1. DailyMed – BUSPIRONE HCL- buspirone hydrochloride tablet. (2019). Retrieved Sept 17, 2020 from https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=33999f17-f689-40a1-955a-fb19c0590e0e
  2. MedlinePlus. (2019). Buspirone. Retrieved on June 23, 2021 from https://medlineplus.gov/druginfo/meds/a688005.html
  3. Simon, L. V. & Keenaghan, M. (2021). Serotonin syndrome. [Updated Jul 22, 2021]. In: StatPearls [Internet]. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK482377/
  4. UpToDate. (n.d.). Buspirone: drug information. Retrieved on June 23, 2021 from https://www.uptodate.com/contents/buspirone-drug-information
  5. Wilson, T. K. & Tripp, J. (2020). Buspirone. [Updated Aug 12, 2021]. In: StatPearls [Internet]. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK531477/