Patients are being warned not to stop taking the valsartan-containing products Dilart and Dilart HCT despite the tablets being subject to a recall because of contamination.

The TGA says the angiotensin II antagonist products have been found to contain trace impurities of a possible carcinogen, N-nitrosodiethylamine (NDEA), but the risk is not great enough to warrant immediate cessation of treatment.

Patients should continue to take the medications until they can be replaced by an alternative valsartan product, the regulator advises.

The recall was issued after impurities were found in batches of valsartan made by an Indian manufacturing plant, and supplied  by Alphapharm (trading as Mylan in Australia).

“While these impurities are classified as probable human carcinogens … they are also commonly found in a variety of foods, particularly smoked and cured meats, some drinking water, in air pollution and are associated with some industrial processes,” the TGA advisory states.

“The risk posed by the impurity at the levels found in these tablets is very low. Patients should not stop their treatment without consulting a doctor or pharmacist, as suddenly stopping high blood pressure medication poses more risk than the impurity.”

Patients should be advised to return affected packs of Dilart or Dilart HCT tablets to the pharmacy, and should be provided a full refund and, if possible, offered an equivalent product to ensure continuation of therapy.

The contamination problem is different to the NDMA impurity that affected many valsartan products globally in August 2018, which was traced to manufacturing facilities in China.

The TGA notes that valsartan products supplied by Novartis and Apotex such as Diovan and APO-Valsartan are not affected.