Antianxiety drugs, also called anxiolytics, include some of themost commonly prescribed drugs in the United States. They are used primarily to treat anxiety disorders. The three main types of antianxiety drugs are benzodiazepines (discussed in a previous section), barbiturates (also discussed in a previous section), and buspirone.
Buspirone is the first antianxiety drug in a class of drugs knownas azaspirodecanedione derivatives. This drug’s structure and mechanism of action differ from those of other antianxiety drugs.
Buspirone has several advantages, including:
· less sedation
· no increase in CNS depressant effects when taken with alcohol or sedative-hypnotics
· lower abuse potential.
Buspirone is absorbed rapidly, undergoes extensive first-pass ef-fect, and is metabolized in the liver to at least one active metabo-lite. The drug is eliminated in urine and stool.
Although the mechanism of action of buspirone isn’t known, it’s known that buspirone doesn’t affect GABA receptors like the ben-zodiazepines do.
Buspirone seems to produce various effects in the midbrain and acts as a midbrain modulator, possibly due to its high affinity for serotonin receptors.
Buspirone is used to treat generalized anxiety states. Patients who haven’t received benzodiazepines seem to respond better to bu-spirone.
Because of its slow onset of action, buspirone is ineffective when quick relief from anxiety is needed.
Unlike other antianxiety drugs, buspirone doesn’t interact with al-cohol or other CNS depressants. When buspirone is given with MAOIs, hypertensive reactions may occur. (See Adverse reactionsto buspirone.)