WASHINGTON - Consider it the other drug problem: Millions of people don't take their medicine correctly - or quit taking it altogether - and the consequences can be deadly.

On average, half of patients with chronic illnesses like heart disease or asthma skip doses or otherwise mess up their medication, says a report being issued later this week that calls the problem a national crisis costing billions of dollars.

The government is preparing new steps to try to persuade patients and their doctors to do better.

But with contributors that range from too-hurried doctor visits to confusing pill bottles, there's no easy solution.

"We go into this with some humility," says Dr. Carolyn Clancy, director of the Agency for Healthcare Research and Quality, which is planning what she calls an "in your face" campaign to improve medication adherence. "It's really pretty appalling how badly we do."

This goes far beyond the issue of affording prescriptions. Often people buy their drugs but misunderstand what they're supposed to take, or how. Or forget doses. Or start feeling better and toss the rest of the bottle. Or skip doses for fear of side effects.

It's not just a problem of poverty or poor education. Even the rich and highly educated skip their medicine. Perhaps the most high-profile example is former President Clinton, who stopped taking his cholesterol-lowering statin drug at some point and later needed open-heart surgery to avoid a major heart attack. Statins offer significant heart protection, but about half of patients on statins quit using them within a year.

And remember the globe-trotting tuberculosis patient who was briefly quarantined in May after ignoring doctors' orders not to travel by airplane? He's out of the hospital now but, like all patients with hard-to-treat TB, must take his remaining antibiotics while health workers watch. So many TB patients skip their pills when they feel better — but before all the bacteria are wiped out — that health departments now enforce what's called "directly observed therapy."

For most diseases, however, patients must choose to take their medicines. The new report combs a decade of research to conclude people generally do a lousy job. Among findings from the nonprofit National Council on Patient Information and Education:

_Particularly at risk are people whose diseases are initially symptom-free. Although high blood pressure more than triples the risk of heart disease, for example, just 51 percent of patients stick with their prescribed antidote.

_Also at high risk are the elderly, but adherence is a problem for all ages. As few as 30 percent of teenagers correctly take drugs to prevent asthma attacks, for example.

_Dire consequences aren't always a deterrent. Among patients already blind in one eye from glaucoma, only 58 percent were protecting the other eye. Another study found 18 percent of kidney transplant recipients weren't following instructions to prevent organ rejection.

_Even doctors mess up, acknowledging in one study adhering to their own prescriptions just 79 percent of the time.

_Poor medication adherence can cost an extra $2,000 a year for each patient in extra doctor visits alone, and it's associated with as many as 40 percent of nursing home admissions, even more costly.

_Add preventable hospitalizations and premature death, and the report estimates that poor medication adherence could be costing the country $177 billion in medical bills and lost productivity.

Why is taking medicines correctly so tough? One reason is the general confusion surrounding drugs, says Dr. Ruth Parker of Emory University, a co-author of the new report who has studied the issue for the American College of Physicians Foundation.

When the pharmacy hands over your prescription, there are bunches of papers — stapled to the bag, outside the box, glued to the bottle — that all bear drug information, but often with different wording. Bottles are covered in warning stickers — such as "Take with food" or "Swallow whole" or "Don't use with XYZ other drug" — in so many colors that Parker compares pill containers to Christmas trees.

What in that jumble should patients pay most attention to?

Then there's the wording. Parker recently helped test the seemingly simple instruction "Take two tablets twice daily." Did that mean a total of two, or a total of four? A third of patients who were deemed literate got confused. A more clear instruction would be: "Take two tablets in the morning and two tablets at night."

Beyond literacy, poor eyesight plays a role. Pill-bottle instructions are pretty tiny.

Whatever the cause, Clancy hopes to make "take your medicine" a new priority. Her Agency for Healthcare Research and Quality is starting discussions with the new report's authors, the Food and Drug Administration and health groups about steps to do that. Options range from attention-grabbing ads about the dangers of misusing medicines to better drug labels.

And in October, the National Council on Patient Information and Education will release Web-based videos designed to train seniors about adhering to their meds.