Drug companies say the plans help some patients afford medicines that they otherwise could not.

But health insurers and some consumer groups say that in many cases, the coupons are just marketing gimmicks that are leading to an overall increase in health care costs. That is because they circumvent the system of higher co-pays on costlier drugs that insurers use to encourage consumers to use less expensive products.

“The member is somewhat insulated from the cost of the prescription,” said Kevin Slavik, senior director of pharmacy at the Health Care Service Corporation, which runs Blue Cross and Blue Shield plans in Illinois and three other states. “In essence, it drives up the total cost of providing the prescription benefit.”

The Food and Drug Administration, meanwhile, is studying the effect of the discounts on consumer perceptions, concerned that the coupons will make consumers believe that a drug is safer or better than it really is.

The acne drug that produced higher costs in 2008 for the Albany insurance company was Solodyn, a once-a-day formulation of an antibiotic called minocycline. A month’s supply of Solodyn sells for more than $700 on drugstore.com, compared with about $40 a month for capsules of generic minocycline, which are generally taken twice a day.

Executives at Medicis, the company that sells Solodyn, have told investors that the co-payment card is used by an “overwhelming majority” of patients, and is largely responsible for doubling use of the drug, to 26,000 prescriptions a week.