HSA to lift ban on Corydalis yanhusuo herb after more than 20 years

The Health Sciences Authority announced that the Corydalis yanhusuo herb, which contains tetrahydropalmatine, will be allowed from June 1, 2018.
The Health Sciences Authority announced that the Corydalis yanhusuo herb, which contains tetrahydropalmatine, will be allowed from June 1, 2018. PHOTO: COLOR ILLUSTRATIONS OF CHINESE MATERIA MEDICA

SINGAPORE - The import and sale of traditional Chinese medicine (TCM) containing tetrahydropalmatine (THP) and the Corydalis yanhusuo herb will be allowed from June 1, the Health Sciences Authority (HSA) said on Sunday (Feb 25).

To ensure their safe use, HSA will review medicines containing THP and Corydalis yanhusuo before permitting their sale here. The authority will also impose a THP dose limit of 19mg per day and additional labelling requirements such as cautionary statements to ensure the safe use of the products.

THP is known for activating blood and moving qi or energy flow, and is generally used to relieve menstrual cramps and headaches, for example. It is a naturally present substance in some herbs, of which the Corydalis yanhusuo is the most commonly used in TCM.

Herbs containing THP have been banned since 1995 by the Ministry of Health. THP was controlled under the Poisons Acts after overseas reports that it could cause liver toxicity when consumed.

The decision to lift the ban was made after a HSA review, following feedback from the Singapore Chinese Medicines and Health Products Merchant Association and a subsequent study by HSA and an expert panel. HSA also studied adverse reactions reported overseas and consulted with the local TCM community.

The review showed no major safety concerns when THP-containing herbs are used appropriately.

However, there is some evidence of an association between high levels of THP and liver toxicity in scientific literature. As a result, HSA will set a daily intake limit of 19mg for THP. It also advises people with liver disease to avoid medicines or herbs which contain THP.

HSA said the review is in line with its efforts to keep health product regulations relevant to industry, while ensuring public health and safety.