Xanax bars are 2-milligram alprazolam pills that are rectangular. These long, tubular pills are sold in 2 mg doses instead of the standard pill Xanax, typically 0.5mg, which means people need to take fewer of them to get a higher amount. While Xanax bars can function as a prescription medication for anxiety, they can also cause harmful side effects, overdose, and dependence. Blue Xanax bars, like most Benzodiazepines, increase the potency of GABA, a neurotransmitter that inhibits neuronal connectivity. This effect calms the nervous system by suppressing neural hyperactivity, the source of anxiety and panic attacks. As a result, a person who consumes a Xanax bar may feel tired and relaxed. A Xanax bar can cause a person to fall asleep in some cases. As a result, some people use Xanax to treat insomnia.