The letters were sent after a group of Democrats unveiled legislation last week aimed to forcing price reductions for prescription drugs, a rare issue where Democrats and President Donald Trump find themselves in some agreement - at least on the basics - of forcing drug companies to lower prices.
Democrats though say that while President Trump has talked about letting Medicare negotiate with major drug companies, the Trump Administration has not followed through on that promise to help consumers deal with rising drug prices.
An initial hearing is scheduled for January 29.
"The cost of prescription drugs is too high in our country and prices just keep rising," said Sen. Kamala Harris (D-CA).
"Don’t let Big Pharma claim that innovation is the reason why the cost of prescription drugs continue to rise," said Rep. Ro Khanna (D-CA).