The Food and Drug Administration (FDA) is recalling 42 batches of high blood pressure drugs from five manufacturers after finding contaminations that may cause cancer.
Dr Narong Aphikulvanich, acting secretary-general of the FDA, said they would retract some models of irbesartan carrying the azidomethyl biphenyl tetrazole (AZBT) impurities, which may increase patients' risk of developing cancer.
However, other models of irbesartan certified by the FDA are safe to consume, Dr Narong said.
The FDA has ordered irbesartan manufacturers to inspect such impurities and replace ingredients carrying AZBT to non-AZBT ones and to recheck their drug distribution in the market.
The announcement followed samples of irbesartan ingredients collected by the FDA from all manufacturers.
Examinations by the Department of Medical Sciences found some models of irbesartan carry impurities which increase risks of cancer at a level higher than international standards.
The FDA ordered a retraction of irbesartan from hospitals, clinics, pharmacies and drug manufacturers, Dr Narong said.
The FDA said patients with high blood pressure are not recommended to quit irbesartan abruptly since hypertension requires consistent drug intake.
However, patients are advised to look into their medication carefully, he added.
The five pharmaceutical companies who distribute the nine irbesartan batches with AZBT impurities are TO Chemicals Co Ltd, Siam Bheasach Co Ltd, M&H Manufacturing Co Ltd, the Government Pharmaceutical Organization and Sriprasit Pharmacy Co Ltd.