Drug copays are changing for thousands of Hawaii Medical Service Association and Kaiser Permanente Hawaii members with some seeing significant increases per prescription.

HMSA said prescription plans changed this year for 55,000 members working for large employers.

In addition to changes in drug copays, the state’s largest health insurer, with 720,000 members, imposed an average 11.1 percent rate hike for large employers this year and raised rates 8.1 percent for small businesses — driven in part by a spike in drug prices.

The out-of-pocket costs for drugs under HMSA’s most prevalent health plan — which most of its members are enrolled in — have jumped in recent years by as much as $100 per prescription for certain specialty drugs, by $10 for brand-name pharmaceuticals and by $2 for generic medicines, according to data from Mercer, a global benefit consulting firm that serves more than 200 Hawaii employers. HMSA declined to confirm those numbers.

“Last year, HMSA employer groups spent 17.4 percent more on prescription drugs to manage chronic conditions like diabetes, high cholesterol, high blood pressure and asthma,” said Elisa Yadao, HMSA senior vice president of consumer experience, in an email. “Some employers chose a drug plan that resulted in a larger co-payment for their employees, others didn’t. We have pharmacists on staff who are ready to work with individuals and their physicians to help ease the impacts of this transition whenever possible.”

Meanwhile, Kaiser Permanente Hawaii — the state’s largest health maintenance organization with 248,000 members — is increasing copays Jan. 1 for about 12,700 patients in its most prevalent plan by $125 for high-cost specialty medications to treat complex conditions. The HMO said that fewer than 1 percent of the members affected by the change currently use specialty drugs.

“Specialty drugs are expensive with some medications costing up to $5,000 or more per dose,” said Kaiser spokeswoman Laura Lott. “This is a national problem. Large pharmaceutical companies are causing a tremendous strain on patients and the entire health care system.”

Large copays are creating barriers to patients getting appropriate care, said Dr. Scott McCaffrey, president of the Hawaii Medical Association, a physicians trade organization with about 1,000 doctors.

“It’s all part of the health care rationing strategy, which creates access-to-care barriers for the patients … shifting the burden of the cost onto the patient or making it difficult to get something done,” he said.

The escalating prices of prescription drugs is largely being driven by high-cost specialty medicines that treat complex diseases such as cancer, multiple sclerosis and hepatitis C, a 2015 Mercer national survey of employer-sponsored health plans shows.

“The reality is the cost of specialty drugs and the utilization of these drugs have increased so dramatically that there’s no free lunch anymore,” said Gary Lee, a principal at Mercer’s Honolulu office. “This is actually what those drugs cost and what they cost HMSA and Kaiser and therefore what HMSA and Kaiser pass on to the employers and members.”