medicines. still, prices of some generics have shot up. a bottle of 500-pill doxycycline has increased from $20 to $1849. these were some of the price increases presented at a congressional hearing in november. congress sent these letters to 14 generic drugmakers calling the ceos of three companies to the hill, but no one came to testify. >> this is rebecca jarvis with abc news. >> we called the companies, too. >> what's going on here? >> all declined interviews. some referred us to the generic pharmaceutical association. >> sometimes there are market forces. there can be drug shortages. there can be an absence of supply or active pharmaceutical ingredients. >> reporter: the generic drug ministry called the hearing misguided, questioned the price information and said its products have saved american consumers billions of dollars. back in salem, new york, some residents now have to drive 30 miles to bring their medications home. one way to push prices lower according to analysts, greater competition.