For the third time in a week, and fifth time in two weeks, a company is recalling a popular blood pressure medication after finding trace amounts of a potentially cancer-causing impurity.

American Health Packaging is voluntarily recalling one lot of Valsartan Tablets, USP, 160 mg. It comes in 100-count blisters with a lot number of 179791 and an expiration date of March 31, 2020. This recall is being initiated in response to a recall by the manufacturer, Aurobindo Pharma USA, which included the affected lot that was repackaged by American Health Packaging.

The initial Aurobindo recall for Valsartan was on Dec. 31, 2018, and expanded on March 1.

RELATED: See the full recall details

The impurity is N-Nitrosodiethylamine (NDEA). It is one of three impurities found in several blood pressure medications since July 2018 which can be a potential human carcinogen.

Patients using Valsartan are advised to keep taking it until they can talk to their doctor about alternatives. Discontinuing use could also pose health risks.

There have been five such recalls since Feb. 22. Three of them were for detection of NDEA and two were for N-Methylnitrosobutyric acid (NMBA). The other possible human carcinogen found in blood pressure drugs since July is N-nitrosodimethylamine (NDMA).

There have been at least 21 recalls, or expansions of recalls, involving blood pressure medication for possible cancer-causing impurities since July 13, 2018.