A pharmaceutical company is once again expanding its recall for blood pressure medications over concerns of potential cancer-causing impurities.

Torrent Pharmaceuticals Limited announced it is including an additional 36 lots of Losartan potassium Tablets USP and 68 lots of Losartan Potassium/Hydrochlorothiazide Tablets USP in its recall after detecting trace amounts of N-Methylnitrosobutyric acid (NMBA), which is classified as a "potential human carcinogen."

Torrent says it is only recalling lots that contain NMBA "above the acceptable daily intake levels released by the FDA." To date, the company has not received any reports of adverse effects associated with the medications.

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This is the latest in a string of recalls for blood pressure medications since last summer.

Drug companies have recalled hundreds of lots of the blood pressure-lowering medications valsartan, losartan and irbesartan either alone or in combination with other drugs. Trace amounts of other cancer-causing impurities, N-nitrosodimethylamine (NDMA) and N-Nitrosodiethylamine, or NDEA, have also been associated with these recalls.

The first recall was in July 2018 when China's Zhejiang Huahai Pharmaceuticals recalled batches of valsartan for trace amounts of NDMA. Three drug companies in the U.S. distributed the tainted medicine: Major Pharmaceuticals, Teva Pharmaceutical Industries, and Solco Healthcare. Other recalls from Mylan Pharmaceuticals, Aurobindo Pharma USA, Inc., and Torrent Pharmaceuticals Limited followed.

Patients who are taking the medications are advised to continue to do so as the risks of stopping immediately without an alternative is considered to be greater. Patients should contact their pharmacist or health care provider who can advise them about an alternative treatment prior to returning their medication.

To see a list of the product/lots included in the expanded recall, visit the FDA's website. A full list of all the recalled medications is also available.