HSA to lift ban on pain-relieving TCM herb

Corydalis yanhusuo is generally used to relieve pain, such as for menstrual cramps and headaches.
Corydalis yanhusuo is generally used to relieve pain, such as for menstrual cramps and headaches.PHOTO: CHINESE MATERIA MEDICA

The import and sale of pain-relieving herb Corydalis yanhusuo will be allowed from June 1, said Senior Minister of State for Health Chee Hong Tat yesterday.

He said the herb has "good pain-relieving and sedative effects that cannot be completely substituted by other Chinese herbs".

Mr Chee was speaking at a Chinese New Year event held by the Singapore Chinese Medicines and Health Products Merchant Association.

Corydalis yanhusuo is known for activating blood and moving qi or energy flow, and is generally used to relieve pain, such as for menstrual cramps and headaches. It contains tetrahydropalmatine (THP), which was listed under the Poisons Act in 1995 after overseas reports said it could cause liver toxicity.

Mr Chee said there were "no major safety concerns" as the potential risks of liver toxicity "can be managed through the implementation of safeguards".

The Health Sciences Authority (HSA) will set a daily intake limit of 19mg for THP, and advise people with liver disease to avoid medicines or herbs with the substance. It will also impose additional labelling requirements, such as consumption advice, and will review medicines before permitting its sale here.

The decision to lift the ban was made after a review by HSA, and a subsequent study by HSA and an expert panel. The authority also studied adverse reactions reported overseas and consulted the local traditional Chinese medicine (TCM) community.

The review showed no major safety concerns when herbs containing THP are used appropriately, though there is some evidence of an association between high levels of THP and liver toxicity in scientific literature.

The Singapore Chinese Medicines and Health Products Merchant Association has been giving feedback on lifting the ban since 2015, said its medicinal section officer, Mr Zhu Wen Jun.

He expects the herb - found in 82 kinds of medication - to be widely used by TCM clinics.

It has been used since the Ming dynasty, and most Asean countries are using it today, he said.

"It is a very important herb, effective against many pains."

Derek Wong

A version of this article appeared in the print edition of The Straits Times on February 26, 2018, with the headline 'HSA to lift ban on pain-relieving TCM herb'. Print Edition | Subscribe