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A Singapore Government Agency Website

Nitrosamine impurities in medicines: List of medicines impacted

Find information on medicines that are impacted due to potential nitrosamine impurities 

Necessary actions have been taken to stop the supply or remove products that may pose safety risks to patients from the Singapore market. To ensure patients’ continued access to essential medicines, HSA had also temporarily allowed continued supply of certain medicines that may contain nitrosamine impurities above acceptable levels while companies make the necessary changes to eliminate or reduce the nitrosamines to acceptable levels. The list of medicines impacted are listed below.



Link(s) to further information


Chickenpox, shingles, herpes simplex virus infection

27 Apr 2022 – Product recall

1 Aug 2022 – Product recall

Angiotensin II receptor blockers (ARBs) e.g. candesartan, irbesartan, losartan, olmesartan, valsartan

High blood pressure

28 Mar 2019 – Product recall


Type 2 diabetes mellitus

4 Dec 2019 – Product recall


Indigestion, heartburn, gastric ulcers

16 Sep 2019 – Product recall



23 Apr 2021 – Update on nitrosamine impurity in rifampicin products


Asthma, chronic bronchitis, emphysema

9 Dec 2021 – Product recall

Sitagliptin Type 2 diabetes mellitus 2 Nov 2022- Update on nitrosamine impurity in sitagliptin products


Smoking cessation

16 Nov 2021 – Product recall