What medication used for anxiety has a delayed onset of action?

Buspirone (BuSpar) is indeed the medication used for anxiety that has a delayed onset of action. Unlike other anxiolytics such as lorazepam (Ativan), which act quickly due to their benzodiazepine properties, buspirone requires several weeks of consistent use to reach its full therapeutic effects.

The mechanism of buspirone's action is thought to involve selective agonism at serotonin receptors (particularly the 5-HT1A receptor) and to a lesser extent, dopamine receptors, which contribute to its gradually increasing efficacy. This is in contrast to medications with immediate effects on the central nervous system, which provide rapid relief of anxiety symptoms.

The delayed onset makes buspirone more suitable for chronic anxiety conditions rather than acute anxiety attacks, offering a different therapeutic approach compared to faster-acting options. Its long-term use does not carry the risk of dependence often seen with benzodiazepines, making it a preferred option for some patients in managing anxiety disorders.