State health officials are encouraging an estimated 26,000 senior citizens to consider signing up for the Medicare prescription drug plan well before the May 15 deadline to avoid a backlog.

Pamela Cunningham, program director of the state's Executive Office on Aging Sage PLUS Program, wants senior citizens to enroll in what's known as "Medicare Part D" by Thursday to avoid a bottleneck of applications when the deadline hits on May 15.

"Nationwide, everybody's concerned that we don't want everyone calling in on May 15," Cunningham said.

An estimated 186,157 senior citizens in the Islands are believed to be eligible for the program, but 150,000 have prescription drug plans that are as good as or better than the new Medicare program. Another 10,000 senior citizens signed up for new plans, leaving an estimated 26,000 who may still benefit from Medicare Part D, Cunningham said.

"It's OK if they feel they don't need it, as long as they realize that down the road there might be a penalty or they might not get into it later," Cunningham said. "It's a personal choice — as long as they know."

Cunningham's office has been receiving as many as 60 calls per day from senior citizens seeking help in comparing the various plans.

"A lot are still sitting back and waiting," she said. "If they want to enroll, that's great. If they don't want to, that's OK, too — as long as they understand that if something catastrophic happens they might not have coverage."

Medicare's goal is to provide a drug benefit program beginning in January that officials call the most sweeping change in the organization's 40-year history.

Locally, state and Medicare officials say that retired county, state and federal employees have plans that are better than what Medicare will offer. The same is true of many retired union members and many veterans.

The premium for the Medi-care drug plan is estimated at about $27 each month in Hawai'i, which would be the lowest in the country after Minnesota.

Senior citizens in the plan also will have to pay the first $250 of their drug costs each year — and 25 percent of their drug costs from $250 to $2,250.

For many senior citizens, the most difficult part will be figuring out whether their current — or future — drug costs will run from $2,250 to $5,100 per year. If their costs fall into what the AARP calls the "doughnut hole" of $2,250 to $5,100 per year, senior citizens in the program will have to pay 100 percent of their drug costs.

But if their costs are higher, Medicare will then pay 95 percent of their expenses after the senior citizen has paid $3,600 per year in out-of-pocket costs.

It's those kinds of calculations — and the forecasts of their future drug needs — that are confusing senior citizens across the country.