The effect of the 14-fold price increase on Aug 27, 2007 of ACTH treatment of infantile spasms in the US was evaluated at University of Colorado, Denver, in 97 patients treated 2007-2009. Before the price increase, patients were more likely to be treated with ACTH as first choice, and were hospitalized for 2.2+/-0.5 SD days for initiation. After price increase, oral AEDs were a more likely first treatment (P<0.002), and those selected for ACTH were hospitalized significantly longer (5.1+/-0.6 days, SD P<0.001). ACTH is considered the most effective treatment for infantile spasms and before 2007, 88% of child neurologists in the US used ACTH as initial therapy. In late 2009, vigabatrin became the only approved drug for infantile spasms in the US. UK studies in 2004 and 2005 found that hormonal treatment more often stopped spasms and improved outcomes than vigabatrin. Since the studies, treatment practices in the UK changed in 2008 in favor of steroids. Whereas the natural form of ACTH is used in the US, accounting in part for the price increase, a synthetic form is used elsewhere. Pricing and availability are influencing the choice of treatment and hospitalization for infantile spasms.