These medications (Uric Acid Inhibitors) work by slowing down the process of converting purines to uric acid (Drug Guide). Purines are chemical compounds found typically in meats and seafood (Diet and Gout).
(Gout Diet Dos and Don'ts).
Smaller amounts of uric acid, fewer crystals form, less pain.
Below is a video providing information on allopurinol. It talks about dosages, how to take it, where to store it, and a few risks.