WASHINGTON  Congressional Democrats said Thursday that they intended to push the Obama administration to back away from its deal with the drug industry to cap its share of the costs in a health care overhaul.

A spokesman for Speaker Nancy Pelosi said she stood by her position that the House was not bound by any such agreement. Ms. Pelosi supports House efforts “to squeeze more money out of the system, including from the pharmaceutical industry,” her spokesman, Nadeam Elshami, said in a statement.

Representative Henry A. Waxman, the California Democrat who heads the Energy and Commerce Committee and helped write the House health care bill, vowed to fight the White House, asserting that it was conceding too much to the powerful drug industry lobby, PhRMA.

“PhRMA would like to see if they can get a bargain,” Mr. Waxman said. “I think that PhRMA should contribute more than PhRMA wants to contribute.”