ORLANDO, Fla. — Give people free prescription drugs and many of them still won’t bother to take their medicine.

Doctors were stunned to see that happen in a major study involving heart attack survivors. The patients were offered well-established drugs to prevent a recurrence of heart trouble, including cholesterol-lowering statins and medicines that slow the heart and help it pump more effectively.

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In a study, a large number of heart patients who were put on cholesterol-lowering statin drugs like Lipitor, above, and other medicines didn’t take them even the pills could prevent more problems. The Associated Press

“My God, we gave these people the medicines for free and only half took it,” said one of the study’s authors, Dr. Elliott Antman of Harvard-affiliated Brigham and Women’s Hospital in Boston.

In fact, the researchers couldn’t even give the stuff away: They had trouble just signing up patients to take part in the study.

Nevertheless, Aetna, the insurance company that footed the bill, thinks this approach will save money in the long run and plans to start offering certain heart drugs free to some patients. In the study, patients offered medicines at no cost suffered fewer heart problems and saved $500 on average over roughly a year.

It is no secret that many Americans don’t follow their doctors’ instructions. In one survey, one-third said they didn’t fill a prescription or used less medicine than they should because of cost. The researchers in this study wanted to see what would happen if they took cost out of the equation.

The results were disheartening. “Adherence in America is miserable,” lamented Dr. Eric Peterson of Duke University, who had no role in the study. He noted that only 10 percent of the patients were taking all the medicines they should one year after a heart attack.

The study was led by Dr. Niteesh Choudhry of Brigham and Women’s, who presented the findings Monday at an American Heart Association conference in Florida. They also were published online by The New England Journal of Medicine.

The study did not examine why people didn’t take their medications. But doctors know that some forget. Most of these drugs mean three pills a day or more, for the rest of a patient’s life. Also, some of these medicines carry side effects such as fatigue, lightheadedness, muscle pains, cough, even sexual difficulties for men.

Still, heart attack survivors like Joan Ferraro, 53, of Freehold, N.J., said they can’t imagine not taking prescribed medicines, though she sometimes forgets her pills over a weekend.

“Why would you want to go through something like that again? It was the most horrific experience of my life. I would never want another one,” she said.

The study enrolled 5,855 Aetna members who had a drug plan as part of their benefits and were going home from the hospital after a heart attack. They were 53 years old on average, and three-fourths were men.

Preventive medicines were offered free to 2,845 patients, and prescribed with the usual co-payments for the rest. Co-pays for these drugs run around $50 a month.

Roughly a year later, the share of patients who filled their prescriptions ranged from 36 percent to 49 percent in the co-pay group, depending on the drug, and was only 4 to 6 percentage points higher in the group that had no co-pays.

The total number of heart attacks, strokes, cases of chest pain or heart failure and other such problems was significantly lower in the group offered free medicine.

That meant that an additional 2 of every 100 people were spared such problems because they were offered free medicines. Doctors suspect the difference between the groups would have been greater if more people had actually filled their prescriptions.

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