Drug alert: Health product Heng Tong Jiangtangning Jiaonang contains undeclared Western drug ingredients that can cause side effects.

The Department of Health warns consumers to avoid health product Heng Tong Jiangtangning Jiaonang which has undeclared Western drug ingredients that can cause side effects.

An 82-year-old woman who took it developed a low blood sugar level and was admitted to Tseung Kwan O Hospital on May 5. She recovered and was discharged on May 7.

The product was prescribed by a local listed Chinese medicine practitioner and imported from the Mainland. It contains phenformin and glibenclamide, which can lead to low blood sugar if incorrectly used.

Phenformin, once used to manage diabetes, was banned as it was associated with an unacceptably high incidence of lactic acidosis (build up of lactic acid in the blood) which could be fatal.

Glibenclamide, which can cause nausea and gastro-intestinal upsets, should only be used under medical supervision. Products containing glibenclamide are third-schedule poisons under the Pharmacy & Poisons Ordinance and can only be sold on a doctor's prescription and under a pharmacist's supervision.

The department has no record of the health product being imported into Hong Kong for sale, or having been submitted for registration. People who have been using it are advised to dispose of it and seek medical advice.