The Swissmedic Official Medicines Control Laboratory (OMCL) has been testing sartans for contamination with the nitrosamine NDMA (N-nitrosodimethylamine) since July 2018. Medicines currently available on the Swiss market containing the active substances valsartan, losartan, olmesartan, candesartan and irbesartan satisfy the requirements in respect of NDMA. The investigations for other impurities will be continued.
In July 2018, drug manufacturers recalled proprietary medicines containing the active ingredient valsartan from the market due to contamination with NDMA. The affected batches contained the active substance produced by the Chinese manufacturer Zhejiang Huahai Pharmaceutical. The reason for the contamination was a change to the synthesis process in the manufacture of the active substance.
As a precaution, Swissmedic has arranged for other medicinal products with sartans that are currently authorised and available on the Swiss market to be investigated for unacceptable contamination with NDMA in order to rule out any production-related impurities.
Like valsartan, losartan, olmesartan, candesartan and irbesartan contain a specific ring system ("tetrazole ring"), and – depending on the manufacturing process – contamination with nitrosamines can occur during the formation (synthesis) of this system. Since this ring system is lacking in other sartan-based substances (azilsartan, eprosartan, telmisartan), these are not affected by the nitrosamine problem.
NDMA contamination: Sartan preparations safe
Medicines currently available on the Swiss market containing the active substances valsartan, losartan, olmesartan, candesartan and irbesartan satisfy the requirements in respect of NDMA contamination.
Further tests for nitrosamines required
As part of the worldwide investigation of NDMA contamination of valsartan, unacceptable levels of NDMA were found in active substances from other manufacturers (Zhejiang Tianyu, Hetero Labs Limited, Aurobindo). Traces of another nitrosamine (N-nitrosodiethylamine, NDEA) have been detected in other sartans (no sartan medicines containing the affected active substances are currently on the market in Switzerland).
These cases show that the initiated analytical monitoring of sartans will need to be continued. The OMCL is currently testing active substances and proprietary medicines containing sartans for possible contamination with NDEA. The first results are expected in November 2018.
The sartan group of medicinal products include preparations containing the active substances valsartan, losartan, olmesartan, candesartan and irbesartan, as well as a number of other active substances. These medicinal products are also known as angiotensin II receptor antagonists.
Sartans have antihypertensive and vasodilatory effects and are used for the treatment of high blood pressure, heart failure or kidney disorders. Most sartans are available in the form of tablets or film-coated tablets, alone or in combination with other active substances.