Despite wide variations in drugs covered by Medicare prescription plans, seniors generally have access to at least one drug in the treatment category they need. The problem, according to a study released this week, is that doctors have a tough time figuring out which drug is covered. Patients often discover their drug isn't covered only when they arrive at a pharmacy. 

"It's virtually impossible for the doctor to get reasonable cost information about a drug for a specific patient ahead of time," said Dr. R. Adams Dudley of UCSF, one of the authors of the study published Tuesday in the Journal of the American Medical Association. 

Medicare, through private companies, began in 2006 to offer a drug benefit to its nearly 44 million elderly or disabled beneficiaries, many of whom had no prescription drug coverage. 

The federal government requires the plans to offer medications in certain classes, but does not dictate exactly which drugs the plans have to cover. Complicating matters further is the large number of plans sold throughout the country. 

Researchers looked at the recent Medicare drug-benefit plans offered in California, which has 69 plans and the highest number of beneficiaries, and Hawaii, which has 33 plans and a relatively small number of patients. 

The study, which concentrated on 75 medications, found that just 45 percent were widely covered. 

But that's not as bad as it sounds. When researchers looked at specific classes, such as cholesterol-lowering agents called statins, they found at least one widely covered drug in almost every class. For example, among statins, all plans covered generic Mevacor while 71 percent covered Zocor and 65 percent covered Lipitor. The latter two are patented brand-name drugs. 

But without knowing which plans cover which drugs, doctors don't know what drugs to prescribe their patients, UCSF's Dudley said. And simply prescribing generic medications, which are more widely covered than brand-name drugs, doesn't solve matters because about 10 percent of generics are not covered. 

"Fundamentally, this is not a coverage problem. This is an information problem," he said. 
Dudley said the problem could be solved through technology, such as a Web site that would provide current, easy-to-find drug coverage information. 

Medicare officials said they are constantly looking for ways to improve the prescription drug program. 

"Obviously, we want to minimize the burden on the physician. It's in everyone's best interest," said Aaron Hase, spokesman for the Centers for Medicare and Medicaid Services. Hase said he is not aware of an effort to provide drug information for doctors online.