[10][11] Common side effects of buspirone include nausea, headaches, dizziness, and difficulty concentrating.

[21] The drug is similarly effective in the treatment of generalized anxiety disorder (GAD) to benzodiazepines including diazepam, alprazolam, lorazepam, and clorazepate.

[26] SSRI and SNRI antidepressants such as paroxetine and venlafaxine, respectively, may cause jaw pain/jaw spasm reversible syndrome, although it is not common, and buspirone appears to be successful in treating antidepressant-induced bruxism.

[3] Buspirone is relatively well tolerated and is not associated with sedation, cognitive and psychomotor impairment, muscle relaxation, physical dependence, or anticonvulsant effects.

[31] In one clinical trial, buspirone was administered to healthy male volunteers at a dosage of 375 mg/day, and produced side effects including nausea, vomiting, dizziness, drowsiness, miosis, and gastric distress.

[16][17][19] In early clinical trials, buspirone was given at dosages even as high as 2,400 mg/day, with akathisia, tremor, and muscle rigidity observed.

[3] It is thought that the main effects of buspirone are mediated via its interaction with the presynaptic 5-HT1A receptor, thus reducing the firing of serotonin-producing neurons.

[38][49] However, buspirone has been reported to have shown "significant and selective intrinsic efficacy" at the α1-adrenergic receptor expressed in a "tissue- and species-dependent manner".

[3][50] Buspirone has a low oral bioavailability of 3.9% relative to intravenous injection due to extensive first-pass metabolism.

[5] Buspirone is metabolized primarily by CYP3A4, and prominent drug interactions with inhibitors and inducers of this enzyme have been observed.

[46][48] Buspirone is a member of the azapirone chemical class, and consists of azaspirodecanedione and pyrimidinylpiperazine components linked together by a butyl chain.

Next, reduction of the nitrile group is performed either by catalytic hydrogenation or with lithium aluminium hydride (LAH) giving (4).

[71] In 2010, in response to a citizen petition, the FDA determined that Buspar was not withdrawn from sale for reasons of safety or effectiveness.