Medical institutions must cooperate with the authorities in the recall of hypertension drugs containing a carcinogenic impurity, the National Health Commission said on Monday. 

On Sunday, China's top drug regulator urged provincial drug authorities to supervise a recall by pharmaceutical companies of all valsartan produced with raw materials supplied by Zhejiang Huahai Pharmaceutical Co, which is based in Linhai, Zhejiang province. 

Huahai reported to the State Drug Administration on July 6 that it had found traces of NDMA, a substance that may cause cancer, in valsartan it produced. The company has recalled all its affected products from the Chinese market.

The National Health Commission said on Monday that no medical institutions could use valsartan drugs covered by the recall, but they can use valsartan made by other companies or other hypertension drugs, based on advice from doctors.