UPDATE: The bill discussed in this post passed the Senate at around 3:30 a.m. Friday by a vote of 57-2.

Legislation that would mandate a $10 “dispensing fee” for filling prescriptions has been amended to exclude self-insured employers and union-negotiated benefits – mostly limiting its impact to smaller employers and individuals.

The bills’ sponsors in the Assembly and Senate made the changes over the past week, apparently in hopes of defusing opposition from big business and organized labor and moving the bill toward passage in the closing days of the legislative session.

The proposal would require the companies that process prescription drug claims on behalf of most health plans – known as pharmacy benefit managers – to pay pharmacies minimum prices for prescription drugs, plus a dispensing fee of $10.18 for each prescription filled. Supporters contend the measure, known as Patient Access to Pharmacy Act, is necessary to protect pharmacists from underpayment by the few large companies that control most of market.

Sponsored by Sen. James Skoufis and Assemblyman John McDonald (who formerly owned a pharmacy) the bill mirrors a regulatory proposal that was dropped by the Department of Financial Services in the face of broad opposition from labor unions, public and private employers, and the health insurance industry.

In testimony against the rule, the Empire Center estimated that the dispensing fee alone would add billions to prescription drug spending, which would contribute to higher costs for taxpayers, employers and health insurance consumers.

The narrowed version of the Skoufis-McDonald bill would reduce that impact by excluding a large share of the state’s insured population. However, it would still tend to increase costs for small employers and individuals, who already pay substantially higher premiums than larger employers.

The time for acting on the revised bill is short: The Senate was due to adjourn for the year on Thursday, and the Assembly was planning to wrap up early next week.