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 shown in the table 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.
Medicine
Use
Publication date
Rifampicin
Tuberculosis
23 Apr 2021
Sitagliptin
Type 2 diabetes mellitus
2 Nov 2022
Ropinirole
Parkinson’s disease
14 Jun 2023
Coronavirus Disease 2019 (COVID-19)HIV infection
5 Mar 2025
24 Mar 2025
Hypertension, angina pectoris, symptomatic chronic heart failure
Depression, panic disorder, obsessive compulsive disorder, post-traumatic stress disorder, social phobia, premenstrual dysphoric disorder
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