Television drug ads that mention a product by name will direct consumers to the drugmaker’s website for additional price information starting April 15, 2019, the largest drug lobbying group said Oct. 15.

That information will include the drug’s list price but also a range of potential out-of-pocket costs patients might have to pay for the drug. Every member of the Pharmaceutical Research and Manufacturers of America agreed to participate in the new initiative, the group’s president, Stephen Ubl, said. That...