The invention is directed to novel pharmaceutical compositions comprising chemicals agents that are useful in the treatment and prevention of cystic fibrosis and the prevention of signs and symptoms of this disease. These pharmaceutical compositions are surprisingly successful in the treatment disorders related to cystic fibrosis including disorders of blood production. Many of these compositions of the invention are even more effective when administered to a patient in pulses. Pulse therapy is not a form of discontinuous administration of the same amount of a composition over time, but comprises administration of the same dose of the composition at a reduced frequency or administration of reduced doses.
