More than 36.9 billion won worth of banned antihypertensive drugs were prescribed last year, according to reports. N-Nitrosodimethylamine (NDMA), a carcinogen, was detected in locally produced antihypertensive medicines containing valsartan, and 59 items were suspended for manufacturing and sales.

The Ministry of Food and Drug Safety announced the research results soon after NDMA was detected in valsartan-containing products made in Korea and banned the manufacturing and sales of 59 valsartan-based hypertension tablets from 22 pharmaceutical companies. The ministry had conducted investigations since NDMA was detected in valsartan-based materials made by China’s Zhejiang Huahai.

NDMA is included in the 2A group -- a substance that may act as a carcinogen to humans -- according to WHO’s International Agency for Research on Cancer (IARC) classification.

The total sales of valsartan-based hypertension drugs produced by 22 companies reached 36.88 billion won last year, according to this paper’s survey. Daewon Pharmaceutical’s X-combi marked the most with 7.97 billion won ($7.08 million), according to IQVIA data, followed by Hutecs Korea Pharmaceutical’s Exforte with 7.41 billion won.

Pfizer’s Norvasc V came in third, marking 66.55 billion won. Norvasc V is a generic of Exforge (amlodipine+valsartan) co-developed by Novartis and Pfizer. It is produced by LG Chem and sold by Pfizer. Pfizer was the only multinational drugmaker that sold NDMA-detected valsartan-based tablets.

Other products that recorded more than 1 billion won of total sales last year include JW Pharmaceutical’s Valsaforce (3.71 billion won), Aju Pharmaceutical’s Anafurge (1.57 billion won), Myungmoon Pharmaceutical’s Exnin (1.12 billion won) and Daehwa Pharmaceutical’s Varoforge (1.01 billion won).