Even for people with health insurance, brand-name prescription drugs can be expensive. If the companies that sell those drugs want to give some patients a little help covering the cost, well, what could be the harm in that?

A lot, it turns out. In the world of health care financing, the battle between drugmakers and insurers is fought with coupons – and the Affordable Care Act might give insurers, and the rest of us, the upper hand.

Coupons for pricy drugs are a bit of a racket. It works like this: Your doctor says you need a drug to, say, treat your depression. Perhaps you ask for a particular brand-name antidepressant; your doctor says a generic version has just been approved but agrees to prescribe the brand you want.

Insurers could refuse to cover brand-name drugs, but then who’d buy their policies? Instead, companies charge you a higher co-payment.

Drugmakers know this, and they offer some patients coupons offsetting that co-payment. You stick with the brand-name drug; the drugmaker gets more revenue, and your insurer is hit with a much higher cost.

Coupons will increase U.S. pharmaceutical spending by up to $32 billion from 2012 to 2021, according to a study paid for by pharmacy benefit managers, who help insurers manage drug costs. That extra spending is passed on to consumers in higher premiums.

Medicare and Medicaid don’t allow coupon programs; until last fall, it looked as though Obamacare might impose the same prohibition on insurance bought on the new state exchanges. Then Health and Human Services Secretary Kathleen Sebelius said the rule didn’t apply; drugmakers say they’re awaiting a final verdict.

For a law with “affordable care” in its title, failing to block coupon programs would be a missed opportunity.