List of impacted medicines

Information on medicines impacted by nitrosamine impurities 

Necessary actions have been taken to stop the supply or remove products that contain nitrosamine impurities above the acceptable levels from the Singapore market. To ensure patients’ continued access to essential medicines, we have also temporarily allowed continued supply of certain medicines that may contain trace amount of 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 in Tables 1 and 2 below.

There is no immediate risk associated with the use of medicines containing trace levels of nitrosamine impurities. Nitrosamine impurities are probable carcinogens based on animal studies where they have been reported to cause cancer only if consumed in very high amounts over a long period of time. The potential risk of cancer is with long-term exposure to unacceptable levels of the impurities.

A very conservative approach is used to set limits for these impurities in medicines, based on what is considered as reasonably safe if a patient continues to take the affected medicine every day for a lifetime of 70 years.

Patients are advised to speak to their doctor or healthcare professional if they have concerns about this issue and should not stop the medicines which has been prescribed to them for their medical conditions on their own. Sudden stopping of the medicines may pose a greater and more immediate health risk than the potential exposure to nitrosamine impurities.

Table 1: Medicines recalled due to nitrosamine impurities



Link to product recall information – Recall date


Chickenpox, shingles, herpes simplex virus infection

27 Apr 2022

1 Aug 2022

16 Aug 2023



6 Feb 2023

16 Aug 2023

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

High blood pressure

28 Mar 2019


Depression, bulimia, obsessive-compulsive disorder

27 Sep 2023


Type 2 diabetes mellitus

4 Dec 2019


Indigestion, heartburn, gastric ulcers

16 Sep 2019


Asthma, chronic bronchitis, emphysema

9 Dec 2021


Type 2 diabetes mellitus

13 Dec 2022


Smoking cessation

16 Nov 2021


Table 2: Medicines that may contain nitrosamine impurities above acceptable levels temporarily allowed for supply



Publication date



23 Apr 2021


Type 2 diabetes mellitus

2 Nov 2022


Parkinson’s disease

14 Jun 2023

Mirabegron Overactive bladder syndrome  29 Apr 2024
Sumatriptan  Migraine 16 May 2024
Entacapone  Parkinson's disease 28 May 2024
Trimetazidine  Ischemic heart disease 28 May 2024 
Duloxetine Depression, Anxiety, Pain 28 May 2024 
Desloratadine  Allergic rhinitis and urticaria  28 May 2024