According to the Times, the co-pay for a 30-day supply of Lipitor will drop to $10 -- the same co-pay as generic versions.
"From a patient perspective, if the copay is the same because the manufacturer is giving a large discount then it's not a major concern," said McBride. "But if the cost of the plan goes up, that's a problem."
But the plan has some doctors crying foul.
"I'm not a pharmacy benefit manager, but it seems to me like it's a bare attempt to maintain some price elevation, some revenue flow from Lipitor sales for as long as possible," said Kesselheim, adding that generic statins are as effective as the brand name drugs. "Certainly there isn't any public health reason that pharmacy benefit managers should stick with brand name Lipitor."
In 2010, Lipitor earned Pfizer more than $5.3 billion in U.S. sales.
ABC News' Kim Carollo contributed to this report.