Can buspirone (anxiolytic medication) cause drowsiness?

Can Buspirone Cause Drowsiness?

Yes, buspirone can cause drowsiness, but it occurs significantly less frequently than with benzodiazepines and is reported in approximately 10% of patients in controlled trials. 1

Incidence of Drowsiness

• In placebo-controlled clinical trials, drowsiness occurred in 10% of buspirone-treated patients compared to 9% of placebo patients, indicating only a minimal increase over baseline 1
• Drowsiness was among the more common adverse events leading to drug discontinuation during premarketing trials, though overall discontinuation rates remained low at approximately 10% for all causes combined 1

Comparative Sedation Profile

Buspirone is distinctly less sedating than traditional anxiolytics:

• Unlike benzodiazepines, buspirone lacks hypnotic, anticonvulsant, and muscle relaxant properties, earning it the designation as "anxioselective" 2
• Studies in healthy volunteers demonstrate that buspirone does not impair psychomotor or cognitive function and appears to have no additive sedative effect when combined with alcohol 2, 3
• The drug produces minimal sedation compared to benzodiazepines, which is a key distinguishing feature 3, 4

Clinical Context and Warnings

Despite lower sedation risk, the FDA label includes important precautions:

• Patients should be cautioned about operating automobiles or complex machinery until they are reasonably certain that buspirone does not affect them adversely, as CNS effects in any individual patient may not be predictable 1
• The most commonly reported CNS adverse effects in controlled trials were dizziness (12%), nervousness (5%), and lightheadedness (3%), with drowsiness ranking fourth at 10% 1

Special Populations

• In elderly patients with anxiety, buspirone can be used with gradual titration starting at 5 mg twice daily, though drowsiness remains a potential side effect 5
• For patients requiring immediate anxiolysis where sedation is acceptable, benzodiazepines like lorazepam remain preferred over buspirone due to buspirone's 2-4 week onset of therapeutic effect 5

Practical Considerations

When drowsiness does occur with buspirone, it is typically:

• Mild in severity and less functionally impairing than benzodiazepine-induced sedation 3
• Not associated with the psychomotor impairment or next-morning residual effects seen with sedative-hypnotics 2, 4
• Less likely to potentiate alcohol's sedative effects compared to benzodiazepines 1, 2