Buspirone is (DNB June 2010)
a. Buspirone is an azapirone derivative with selective antianxiety action.
b. It is a partial agonist of 5-HT1A receptors and has nothing to do with GABAA receptors which are acted upon by benzodiazepines.
c. It is well absorbed orally, undergoes high first pass metabolism and has a cumulative nature. Though, lack of sedation is a major clinical advantage; slow onset of action is a major problem.
d. It takes 1-2 weeks to achieve plasma study state therefore delaying onset of action. As a result, the drug is unreliable in acute phase.
e. Moreover, it is free from anti-seizure and muscle relaxant property. Tolerance, addiction, dependence do not occur with buspirone.
f. It is particularly useful in patients with generalized anxiety disorder who are substance abusers.
g. It is also sometimes used to augment clinical response to anti-depressants. Importantly, efficacy of this drug is lower than benzodiazepines but several of its derivatives have now appeared.
Side effects include gastrointestinal upset and meiosis. Odd patients may experience dysphoric reactions. Sympathetic stimulation is rare.