Buspirone

Buspirone, sold under the name Buspar among others, is an anxiolytic medication primarily used for the treatment of generalized anxiety disorder. Unlike benzodiazepines, buspirone does not produce significant sedation, dependence, or withdrawal effects. Its principal mechanism of action involves partial agonism at postsynaptic serotonin 5-HT₁A receptors and full agonism at presynaptic 5-HT₁A autoreceptors, which initially reduces serotonergic neuron firing. Over time, autoreceptor desensitization occurs, leading to increased serotonin release and enhanced serotonergic tone, which may contribute to its clinical efficacy. Buspirone also has weak antagonistic effects at dopamine D2, D3, and D4 receptors and α1- and α2-adrenergic receptors.

Buspirone is approved for the management of generalized anxiety disorder. It is sometimes used off-label for other anxiety disorders, depression augmentation, and certain behavioral conditions. Buspirone is not effective as a sedative-hypnotic or muscle relaxant and does not have anticonvulsant properties.

Common side effects of buspirone include nausea, headaches, dizziness, and difficulty concentrating. Serious side effects may include movement disorders, serotonin syndrome, and seizures. Its use in pregnancy appears to be safe but has not been well studied, and use during breastfeeding has not been well studied either.

Buspirone was developed in 1968 and approved for medical use in the United States in 1986. It is available as a generic medication. In 2023, it was the 40th most commonly prescribed medication in the United States, with more than 15 million prescriptions.

Buspirone is used for the short-term and long-term treatment of anxiety disorders or symptoms of anxiety. It is generally preferred over benzodiazepines because it does not activate the receptors that make drugs like alprazolam addictive.

Buspirone has no immediate anxiolytic effects, and hence has a delayed onset of action; its full clinical effectiveness may require 2–4 weeks to manifest itself. The drug is effective in the treatment of generalized anxiety disorder (GAD) similar to benzodiazepines including diazepam, alprazolam, lorazepam, and clorazepate. Buspirone is not known to be effective in the treatment of anxiety disorders other than GAD.

There is some evidence that buspirone on its own may be useful in the treatment of hypoactive sexual desire disorder (HSDD) in women. Buspirone may also be effective in treating antidepressant-induced sexual dysfunction.

Buspirone is not effective as a treatment for benzodiazepine withdrawal, barbiturate withdrawal, or alcohol withdrawal.