The pressure on the benefit managers is taking several forms.

The company's experience interests company benefits managers because many are considering the same approach.

Coverage would be administered by a single private benefits manager in each region.

They said it would be open to all pharmacies, health plans and other benefit managers.

Corporate benefits managers said that in spite of efforts to control costs, health care continued to be a big problem for them and their employees.

The money was on the table, and they gave it away to the benefit manager who issued the card.

The system could also lead doctors to switch patients to drugs preferred by benefit managers.

But some corporate benefits managers estimate that their companies are paying 10 to 35 percent less than under conventional programs.

The nation's pharmacy benefits managers handle about 75 percent of the $235 billion spent on prescriptions every year.

Private employers, health plans and consumers also are challenging the benefit managers' practices.