BuSpar (buspirone) is a non-benzodiazepine anxiolytic (antianxiety and antipanic) primarily prescribed to teens and adults to relieve anxiety and associated symptoms. BuSpar was initially developed to be used as an antipsychotic, but it did not prove successful. Instead, it became adopted by clinicians as a non-sedating anxiolytic.

How Does BuSpar Work?

BuSpar is a central nervous system (CNS) selective drug that acts on a single subtype of serotonin (5-HT) receptor. It has high affinity for type 1 serotonergic receptors (5HT-1). The relative affinity is greater for the 5HT-1A receptor compared to that of 5HT-1B and acts as a partial or mixed agonist. This is what causes BuSpar’s anxiolytic activity.

This medication also has moderate affinity for dopamine receptors and may improve the quality of sleep for those experiencing anxiety without having hypnotic or sedative effects.

Dosage FAQs

  • What is a safe dose of this drug?
    To relieve anxiety, a dose of 5 mg should be given two to three times every day. This dose can be increased to 15 mg to 30 mg, but should not exceed 45 mg per day. This medication has a slow onset of action of and may require a period of three to four weeks to attain the proper therapeutic effect.
  • How is this drug processed in my body?
    This medication’s onset of action appears within the first two weeks, but individuals taking this medication may only begin to experience the effects after three to four weeks. This corresponds with a bioavailability beginning at 4%. The protein binding of this medication is around 90% where it mainly binds with albumin. It is metabolized in the liver and is excreted through the body’s passing of urine and feces. It has a half-life of two to three hours. Food may affect its absorption and the timing of administration should be adjusted accordingly.
     

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    Is this drug safe to use during pregnancy?
    BuSpar should only be used during pregnancy if absolutely needed. A thorough assessment should be performed by you and your doctor to determine risk to the mother and fetus. The U.S. Food and Drug Administration (FDA) classifies this medication as a pregnancy category B drug, meaning animal reproduction studies have not demonstrated a risk to the fetus. However, there are no well-controlled studies available for human pregnancies.
     
  • Are there ways to complement my mental health treatment with this drug?
    This medication is primarily prescribed to teens and adults for anxiety-related issues, many of which have a demonstrated history of being effectively treated with types of psychotherapy. Medication can be useful to dull symptoms, but it cannot teach coping strategies, social skills, or self-care in the same manner as a therapist. Pairing your drug treatment with psychotherapy may help you achieve a longer-lasting, better mental health outcome than treatment with drugs alone.

Possible Side Effects

Although BuSpar is well-tolerated by many individuals, some of its adverse effects on various organ systems include:

  • CNS effects: Compared to other anxiolytics, central nervous system effects like psychomotor dysfunction and sedation occur less frequently with this medication. The most common adverse effects of BuSpar include dizziness, headache, and lightheadedness combined with drowsiness.
  • Gastrointestinal effects: Compared with placebos, nausea has been reported in some patients taking this medication. In some clinical studies individuals also experienced dry mouth, gastric distress, diarrhea, constipation, and vomiting.
  • Other effects: Urinary retention or increased frequency of urination, cramps, hyperventilation, dyspnea (shortness of breath), blurred vision, menstrual irregularities, galactorrhea, and thyroid abnormalities have be reported by some individuals, however, there is no formal relation between any of these side effects and BuSpar.

Additionally, although the sedative effects of this drug are less severe when compared to other anxiolytics, individuals must be cautioned about its use when performing activities requiring motor coordination (such as driving or operating machinery). Practice caution until you are sure you know how this drug will affect you.

Adverse Drug Interactions

Like many other anxiolytics, this medication has several interactions of which to be aware, including:

  • Monoamine oxidase inhibitors (MAOIs): The administration of tranylcypromine with this medication may increase blood pressure. It is not recommend to combine this drug with MAOIs.
  • Fluoxetine: During the concomitant administration of BuSpar with trazodone (a tricyclic antidepressant) for individuals experiencing panic attacks, generalized anxiety, and depression, the anxiety symptoms may increase if fluoxetine is added to the regime.
  • Haloperidol: Haloperidol’s concentration in serum increases when it is administered with this medication.
  • Aspirin: Aspirin can increase this medicaton’s serum concentration by displacing it from the plasma protein.
  • Erythromycin, Itraconazole and Nefazodone: These drugs inhibit the liver enzyme responsible for the metabolism of BuSpar. Dosage should be adjusted if combined with these medications.
  • Verapamil and Diltizem: Combining these drugs with BuSpar causes an increase in serum concentration.
  • Rifampin: Rifampin decreases the plasma concentration of this drug due to increased stimulation of liver metabolic activity.
  • Grapefruit juice: Grapefruit and products containing grapefruit should be avoided while taking this medication.
  • Food: Food may delay gastrointestinal absorption.
  • Alcohol: The effects of administering alcohol and this medication together are unpredictable. Alcohol should be avoided while using this medication.

Safe Withdrawal from BuSpar

This drug is not associated with any significant withdrawal symptoms. However, individual physiology may affect the manifestation of symptoms when discontinuing this medication. If you are concerned about withdrawal symptoms, or if you have been taking this drug for an extended period of time, you should consult with your doctor and make sure he or she does not recommend tapering off your dosage. Develop a safe plan to discontinue this medication with your health care provider.

References:

  1. ASHP therapeutic position statement on the recognition and treatment of depression in older adults. (1998). American Journal of Health-System Pharmacy, 55, 2514–2518.
  2. Boyer, E.W. and Shannon, M. (2005). The serotonin syndrome. New England Journal of Medicine, 352, 1112–1120.
  3. Buspirone 10mg Tablets. 10 September 2012.  Electronic Medicines Compendium. Actavis UK Ltd. Retrieved 14 November 2013.
  4. Mendolwicz, M.V. and Stein, M.B. (2000). Quality of life in individuals with anxiety disorders. American Journal of Psychiatry, 157, 722–728.
  5. Rickels, R. and Ryan, M. (2002). Pharmacotherapy of generalized anxiety disorder. Journal of Clinical Psychiatry, 63(suppl. 14), 9–16.
  6. Sramek, J.J., Zarotsky, V., and Cutler, N.R. (2002). Generalised anxiety disorder. Drugs, 62, 1635–1648.

Page content reviewed by James Pendleton, ND.