Buspirone (BuSpar) is a serotonin 5-HT1A receptor partial agonist (SRA) FDA-approved for generalized anxiety disorder (GAD). It is unrelated to other anxiolytics. Buspirone is non-addictive and generally non-sedating. Unlike other medications in this chapter, buspirone works in a slow and steady fashion, like an antidepressant. Contrast this with benzodiazepines, which work immediately but are addictive. Unlike benzodiazepines, buspirone is generally not useful as a PRN anxiolytic because optimum efficacy usually requires 2 to 4 weeks of regular administration. Some patients regard buspirone as an effective PRN, likely due to placebo effect.
“Buspar is benign.” Buspirone is one of the safest psychotropic medications, with no need for laboratory monitoring. There are no absolute contraindications (other than allergy to buspirone). No deaths have been reported with single-drug overdose. It is generally well tolerated, but potential side effects include nausea, headache and jitters. It does not cause weight gain. Withdrawal is not an issue if buspirone is stopped without tapering.
“Buspirone doesn’t have to be used alone!” (Madalyn Hoke, PA-S). Buspirone can be combined with practically any other psychotropic medication, with a couple of exceptions.
Buspirone is avoided with MAOIs, although there is evidence that buspirone does not cause serotonin syndrome (The scoop on serotonin syndrome; Foong et al; Canadian Pharmacists Journal, 2018)
It is redundant to combine buspirone with vilazodone (Viibryd) because vilazodone has intrinsic 5-HT1A receptor partial agonist activity. Pharmacologically, “Viibryd is like a hybrid” of an SSRI and buspirone.
Buspirone is commonly prescribed along with an antidepressant, although caution is advised due to a small possibility of serotonin syndrome. An SSRI plus buspirone is good for anxiety, but there is better evidence for other augmenting agents for treatment-resistant depression (TRD). More effective adjuncts for PLACEHOLDER
TRD include lithium, aripiprazole (Abilify), quetiapine (Seroquel), risperidone (Risperdal), and liothyronine (Cytomel—T3 thyroid hormone). However, buspirone is safer and better tolerated than these more proven adjuncts.
Unlike most serotonergics, buspirone may enhance sexual functioning. Buspirone shares some properties with flibanserin (Addyi), a 5-HT1A receptor agonist approved for hypoactive sexual desire disorder.
Buspirone can serve as an antidote for SSRI-induced bruxism (tooth grinding). Buspirone is used off-label at high dose for treatment of movement disorders including chorea, tardive dyskinesia and levodopa induced dyskinesias. It may improve cognitive functioning in schizophrenia and Alzheimer’s disease. When used for anxiety with alcohol use disorder, it decreases drinking days (Kranzler et al, 1994).
“This school bus ain’t for kids”—Although there are no safety issues, buspirone does not appear to be effective for treatment of GAD in individuals under age 18.
Buspirone has a short half-life of 2–3 hours, so it requires BID or TID dosing (usually TID). Although inconvenient, some patients prefer multiple daily dosing for better perceived control of symptoms. However, it is not expected to be immediately effective. Benefit is achieved gradually over 2–4 weeks, but placebo effect can be a powerful thing.
Dosing: Buspirone is typically started 7.5–10 mg BID or TID and titrated quickly to a target dose of 15 mg TID or 20 mg BID, with FDA maximum dose of 60 mg/day. Starting at 15 mg BID is ok. It is recommended to take buspirone consistently with food or consistently without food, because it is better absorbed when taken with meals. For off-label treatment of movement disorders, it may be necessary to titrate buspirone as high as 180 mg/day. A higher dose of buspirone will be needed if it is combined with a strong 3A4 inDucer such as carbamazepine (Tegretol). Unless the dose is very high, buspirone may be discontinued without tapering.