The urea cycle is a process in which ammonia is removed from the body. When proteins are eaten, the body breaks them down into amino acids. Ammonia is produced from leftover amino acids, and it must be removed from the body. People with a urea cycle disorder are missing a gene that makes the enzymes needed to break down ammonia in the body. Urea cycle disorder agents are prescribed along with changes in diet for long-term treatment of urea cycle disorders. They work by helping rid the body of excess nitrogen waste by bypassing the urea cycle.