The statins are a landmark test of the FDA's thinking on over-the-counter medicines. Traditionally, drugstores carry remedies for short-term problems, such as headaches. But statins have to be taken for a long period of time to tame chronically high cholesterol, which doesn't have symptoms. Patients would have to decide for themselves whether they need the drug, and monitor their own progress.

In the United Kingdom, regulators allow consumers to buy a different statin, Zocor, over-the-counter. But that program included a big role for pharmacists in advising patients, a structure that may not be easy to duplicate in the U.S., where consumers are used to grabbing their medicines off the shelf.

STATIN TARGETS   A proposed over-the-counter 20 milligram dose of Mevacor would be aimed at:   • Men 45 and older and women 55 and older   • With LDL between 130 and 170   • And at least one of these heart-disease risks: a smoker; HDL (good cholesterol) of 39 or under; high blood pressure; heart disease in a father or brother before age 55 or in a mother or sister before 65     Source: Merck & Co.

In the U.S., where an FDA advisory panel in 2000 turned down over-the-counter requests for Mevacor and Pravachol, many doctors remain skeptical that consumers can manage their own risks for something as serious as heart disease. "Statins are strong medicines for a condition that is potentially life-threatening," says Steven Nissen, a cardiologist at the Cleveland Clinic. They "should be prescribed by physicians with the training and experience...to choose the right thing for the right patient at the right time."

People who have suffered a heart attack or are otherwise at high risk of cardiovascular disease are candidates for aggressive treatment with high-dose statins. The goal is to get their LDL, or "bad," cholesterol to as low as below 70. The aim with a less-potent over-the-counter statin would be to avoid a first heart attack or stroke in patients at intermediate risk. The joint venture, Johnson & Johnson/Merck, says that amounts to 15 million to 20 million Americans, whose LDL is moderately elevated -- between 130 and 170. National guidelines advise them to get LDL below 130. Yet only three million to five million of them are getting treatment because, among other reasons, they aren't seeing a doctor regularly, they lack insurance or their doctors aren't effectively monitoring their risks.

Switching to over-the-counter would ease access and potentially reduce costs, the drug makers say. And at 20 milligrams, the companies say the Mevacor dosage would be effective enough to reduce LDL in this moderate-risk population while still having a low risk of side effects.

Merck and Johnson & Johnson say their program can ensure that the right patients take Mevacor. The plan entails a "self management system" that includes, among other things, detailed criteria noted in the packaging to help consumers decide whether their LDL cholesterol, age and other risk factors make them candidates for Mevacor. The packaging also directs consumers to a Web site and a toll-free call center for information and a cholesterol-testing referral service. Consumers are encouraged to contact their doctors.

As a test of how well consumers can choose, the companies mounted an unusual study intended to mimic real-world practice. They set up 14 mock storefront drugstores in seven regions of the U.S., with products lined up on shelves and a nurse to represent a pharmacist. They recruited customers to come in and consider Mevacor as an over-the-counter drug. All told, 3,316 people showed up, of whom 1,061 decided to purchase the medicine. These people then were tracked for six months.

The companies' researchers concluded that 84% of the participants made an "appropriate" initial decision on whether to purchase the drug, based on whether they met criteria listed in the product label. But that number included everyone who decided against making a purchase: The companies viewed those consumers as having made a correct decision, though there was no follow-up.

Of the consumers who did choose to take the drug, 66% met or came close to meeting the criteria, according to the analysis. During the study, 23 participants, or 2%, either took Mevacor with drugs that could cause adverse reactions or otherwise used the medicine in a fashion that raised risks, though no serious consequences resulted.

The study, which was published in November in the American Journal of Cardiology, found that of 878 participants who had their cholesterol measured after six months, 548, or 62%, got their LDL to a target below 130. And the study prompted many participants to contact their doctors -- a result company officials regard as an indication the program works.

But the FDA said the study didn't reflect real-world conditions. According to the FDA's own analysis, just 55% of participants made the right decision about whether to take Mevacor, and only 41% correctly continued to use the drug by the sixth week. The biggest problem was that consumers didn't know their total cholesterol profile. Among people who said they did know, only half accurately identified their LDL.

The FDA also raised questions about whether consumers would use a statin safely without oversight from a doctor. The FDA reviewer cautioned that because the study limited the amount of Mevacor consumers could buy, it didn't truly reflect the risk of overdosing. The agency also questioned whether consumers should take the drug without a requirement for a doctor to test periodically for liver problems, a possible side effect of statins, and whether patients would be cautious enough about interactions with other drugs and substances.

Statins have built up an impressive record on both safety and effectiveness during more than 15 years on the market. But the class has blemishes too: Bayer AG pulled its statin Baycol from the market in 2001 because of a heightened risk of a very rare but potentially lethal muscle-wasting side effect called rhabdomyolysis, and AstraZeneca PLC's Crestor has been hobbled by worries about similar side effects, especially at high doses.

Another concern is that patients at high risk of heart attack or stroke might not get all the treatment they need. "We would not want people who had heart disease that required very aggressive treatment to think that all they need to do is take a low-dose statin," says Sidney Smith, a cardiologist at the University of North Carolina at Chapel Hill.

Write to Ron Winslow at ron.winslow@wsj.com¹ and Anna Wilde Mathews at anna.mathews@wsj.com²