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If you want to avoid potential adverse reactions from prescription drugs you should shy away from new medications that have been on the market for less than two years, a health-systems expert warns.

"It is assumed by the general public that new drugs ... have been put through exhaustive trials and found to be safe and effective," said Donald Light, a sociology professor at the University of Medicine and Dentistry of New Jersey. But, he added, new products are not necessarily better or safer than drugs already available.

In fact, reviews of the medical literature reveal that only one in seven new drugs is superior to existing medications. What's more, two out of every seven new drugs result in side effects serious enough to eventually warrant special warnings or even withdrawal from the market.

And a big problem is that many of these adverse reactions don't become apparent until a drug has been used by millions of patients for several years.

That's why Dr. Light suggests that patients who are doing fine on their existing prescriptions should not quickly switch to a newly introduced medication.

"Don't take any new drug, unless you absolutely have to, for two years."

And to drive home that message, he would like to see the following warning printed on the labels of every new drug: "Apparently safe based on incomplete information, and more effective than a placebo."

He points out that new drugs are generally tested against inactive placebos before being approved for consumer use, not necessarily the drugs they will be competing against.

Treating Anemia

Many people who suffer from chronic illnesses also develop anemia, which is a shortage of the red blood cells that ferry oxygen around the body.

Doctors normally consider anemia to be a bad thing, and often treat it with blood transfusions or drugs that stimulate the body to produce more of its own red blood cells.

But two Canadian doctors - Donald Houston of the University of Manitoba and Ryan Zarychanski of the Ottawa Health Research Institute - have put forward a provocative theory that challenges this traditional approach to a common medical condition.

They argue, in a recent edition of the Canadian Medical Association Journal, that mild to moderate anemia may be part of the body's natural healing process and that trying to counteract it with medical treatments could do the patient more harm than good.

"As part of the mechanism of anemia ... the body locks away iron," Dr. Houston explained in an interview. "Iron is a component of the hemoglobin molecule that carries oxygen [in red blood cells]."

So, curbing the availability of iron leads to a decline in red blood cell production, thereby resulting in the classic symptoms of anemia, including lethargy.

But less iron can also be beneficial, Dr. Houston speculated. For instance, cutting back on iron may help fight infections because iron is an essential nutrient required for the growth of many micro-organisms. "Iron may also have some role in helping tumours grow."

Furthermore, having fewer red blood cells in circulation may reduce strain on the heart. "It requires less energy to pump the blood around," he said.

Dr. Houston pointed to previous studies that found an elevated risk of death among some patients receiving drugs to treat anemia.

"I don't want people to get the wrong idea. Some kinds of anemia are definitely bad. Severe anemia is definitely bad. Blood transfusions and drugs can be, are, very useful ... in moderate doses in these cases," he stressed. "But pushing the hemoglobin all the way up to normal in people with chronic disease looks to be harmful."

He added that more research is needed. "What I really hope is that [the journal article] generates good studies so we can answer some of the questions that we have raised," Dr. Houston said.

Buyer beware

About one-fifth of the Ayurvedic medicines sold over the Internet contain hazardous lead, mercury and arsenic, according to researchers at Boston University's school of medicine.

Ayurveda, an ancient healing practice from India, relies on a variety of herbal products.

The researchers selected 25 websites selling Ayurvedic medicines. They randomly purchased 193 products, then analyzed them in a lab. Over all, 20.7 per cent of the medicines, which were manufactured in India and the United States, contained detectable levels of lead, mercury and/or arsenic.

The study, published in the Journal of the American Medical Association, is not the first to raise questions about the safety of drugs and supplements hawked on the Web. But it serves as a good reminder that the old adage "let the buyer beware" certainly applies to the Internet.