SUMMARIES FOR PATIENTS

Liver Injury in 12 Patients Taking the Herbal Weight Loss Aids Chaso or Onshido

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The summary below is from the full report titled "Hepatic Injury in 12 Patients Taking the Herbal Weight Loss Aids Chaso or Onshido." It is in the 16 September 2003 issue of Annals of Internal Medicine (volume 139, pages 488-492). The authors are M. Adachi, H. Saito, H. Kobayashi, Y. Horie, S. Kato, M. Yoshioka, and H. Ishii.

What is the problem and what is known about it so far?

Various herbal supplements are sold as weight loss aids. In many countries, including the United States, the authorities consider these products to be dietary supplements, not drugs. People can buy them without prescriptions, and the products are not subject to the same standards as drugs. In the United States, a drug company cannot sell a drug until it provides the U.S. Food and Drug Administration (FDA) with studies of its effectiveness and safety. The FDA approves a drug with potential dangerous side effects only after studies are done to show what these side effects might be. Doctors and patients can use this information to decide whether the risks of the drug are worth its potential benefits. Similar studies are not required before a company sells a dietary supplement, including herbal weight loss aids.

Chaso and Onshido are 2 herbal weight loss aids that have gained popularity in Japan. These products are made in China but are available for purchase over the Internet. In August 2002, after reports of liver problems that developed in Japanese patients who took Chaso, the FDA alerted the U.S. public about Chinese weight loss products because they pose a potential public health risk.

Why did the researchers do this particular study?

To describe a series of patients who developed liver problems while taking the herbal weight loss aids Chaso or Onshido.

Who was studied?

12 patients who presented to Japanese hospitals with liver problems while taking Chaso or Onshido.

How was the study done?

The researchers reviewed the records of the 12 patients to collect information about their medical history, their use of drugs and herbal products, and possible causes of the liver problems. They also did a chemical analysis of the herbal products that the patients took to see what substances they contained.

What did the researchers find?

The 12 patients developed symptoms 5 to 45 days after taking the manufacturer’s recommended dose of the product. Symptoms included fatigue, decreased appetite, nausea, and diarrhea. When patients sought medical care, they had abnormal liver test results. The researchers could not find other potential causes of the liver problems in any patient. Two of the 12 patients developed severe liver failure; 1 died and the other needed a liver transplant. The other patients all recovered after stopping the use of Chaso or Onshido. Chemical tests of the products identified the substance n-nitroso-fenfluramine. Fenfluramine is a drug that had been used for weight loss but was taken off the market after it was found to be associated with heart problems.

What were the limitations of the study?

This report of 12 cases presented to 1 of several Japanese hospitals cannot tell us how often patients develop liver problems while taking Chaso or Onshido. It also cannot prove that the n-nitroso-fenfluramine is the substance responsible for the liver problems.

What are the implications of the study?

People who are considering using Chaso or Onshido should be aware that these weight loss aids might contain the chemical n-nitroso-fenfluramine and might cause liver problems. People should not assume that herbal weight loss aids are safe.