RxList says that Xanax comes in tablets containing 0.25, 0.5, 1 or 2 milligrams of the drug alprazolam. The 0.5 milligram tablet is yellow, and the 1 milligram tablet is blue. The 2 milligram tablet is scored, allowing it to be broken into two or four equal parts easily.
Drugs.com explains that patients with anxiety disorders are prescribed 0.25 to 0.5 milligrams to be taken three times daily. Individuals with panic disorder may require much higher doses to control their symptoms, with some requiring as much as 10 milligrams per day. Individuals with anxiety or panic disorder often need to experiment with dosages in order to find the lowest possible effective dose.