BOSTON -- Ten years ago, we had no medicines to treat Alzheimer's disease.

Now we have four -- and a dozen or so more in clinical testing. But blockbuster drugs have come at a price -- one oftentimes too expensive for consumers and even insurers to pay.

In Part Three of a series on the rising costs of prescription drugs, NewsCenter 5 medical editor Dr. Timothy Johnson explores how hidden deals between pharmaceutical companies, doctors, hospitals and others can drive up the cost.

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Some TV commercials represent the dawn of a new era in prescription drug advertising. They never mention the name of a drug. Instead these newer commercials are made to educate, describing the symptoms of a disease and then send viewers to a Web site, where there is a phone number for more information.

"There are millions of Americans who have diabetes and don't know it, who have depression and don't seek treatment for it. So the more information we get out to patients -- the better off our overall healthcare system will be," PhRMA President Alan Holmer said.

Drug advertising does benefit the consumer. For example, learning about Viagra may be one reason more men are visiting their doctors. But make no mistake, these ads are not made simply to educate, they are also made to make money.

"They're trying to create demand by the public, they're trying to influence docs to get them to prescribe their drugs and the one thing I know, because they're very smart, drug companies, that they wouldn't do this if it didn't work," Boston University School of Public Health Dr. Michael Grodin said.

If the sales pitch in drug ads is often hidden, so is the growing influence of the industry on all aspects of the system -- from how drugs receive government approval to the results of studies that show whether or not they work.

Jerome Kassirer was editor of the New England Journal of Medicine and is now writing a book on ethical practices surrounding the pharmaceutical industry.

"(Drug companies) put (researchers) on their boards as consultants. They give them honoraria to give speeches, and in some sense, many of them end up in the pocket of the pharmaceutical company," Kassirer said.

"They treat doctors to lunches, and they meet with them on a regular basis, and they give them, of course, drugs to try out. It turns out that what they do is use the more expensive drugs," Kassirer said.

Documents in a criminal case against TAP Pharmaceuticals show that when the Lahey Clinic threatened to switch from the expensive prostate cancer fighter Lupron to a less expensive alternative, the drug company promised to pay for a lavish Christmas party, seminars and research.

Many doctors said that they do feel pressure on a daily basis.

"There are days when I have 10 to 15 pharmaceutical reps in my office," Dr. Patricia Hopkins said. "We have had to shut the door and not allow them in because they confuse their role as agents of information with agents of friendship and entertainment."

The drug industry itself is trying to impose its own set of guidelines to cut down on these practices, and as some point out, the fault is not just the drug companies. Every prescription for every medication must be written by a doctor. Some said that more than guidelines will be needed.

"You need fines. You need jail time. You need laws that mean something because what's at stake here is the well-being and sometimes the lives of patients," Massachusetts Medical Society Dr. Charlie Welch said.

Obviously, that's a strong prescription for change. But many experts said that strong medicine is exactly what's needed.