Glyburide belongs to a class of drugs called sulfonylureas and is used to treat type-2 diabetes. It lowers blood sugar levels by stimulating the pancreas to secrete insulin and helping the body use it efficiently.
Although the FDA says glyburide is safe and efficacious when used as labelled in approved medications, in its alert it says that people with low blood sugar or diabetes can receive dangerously high amounts of the drug if they take Ligiang 4.
Anyone who has been taking it - and in particular anyone also taking diabetes drugs - is advised to cease immediately and seek medical attention. The danger signs, says the FDA, are fatigue, excessive hunger, profuse sweating, or numbness of the extremities.
The government agency carried out testing to establish the presence of glyburide in the supplement following a complaint from a consumer. It is also carrying out tests on other products in the same line, including Ligiang 1 with which Ligiang 4 is sold as a bonus product.
Ligiang 4 is made by the Ligiang Research Institute in China and has been sold in the United States in health food stores and by mail order through Bugle International in Northridge, California.
It has been promoted in Chinese-language advertisements as an all-natural product to control diabetes, and also goes by the name Liqiang Xiao Ke Ling, meaning 'Liqiang Thirst Quenching Efficacious'.
This is not the first time that the FDA has identified glyburide in dietary supplements of Chinese origin. In 2000 Sino American Health Products of Torrance, California, withdrew two glyburide-containing products from market - Zhen Qi Herbal Extract Capsules and Diabetes Angel Pearl Hypoglycemic Capsules, made by Tongyi Tang Pharmaceuticals Company, Harbin, China - following FDA warnings.