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 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.
Medicines that may contain nitrosamine impurities above acceptable levels temporarily allowed for supply
Medicine | Use | Publication date |
Rifampicin | Tuberculosis | |
Sitagliptin | Type 2 diabetes mellitus | |
Ropinirole | 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, urticaria | 28 May 2024 |
Fluoxetine | Depression, bulimia nervosa, obsessive compulsive disorder, premenstrual dysphoric disorder | 20 Sep 2024 |
Cinacalcet | Secondary hyperparathyroidism | 19 Nov 2024 |
Ritonavir | Coronavirus Disease 2019 (COVID-19) | 5 Mar 2025
|
Amitriptyline | Depression, enuresis | 15 Sep 2025 |
Carvedilol | Hypertension, angina pectoris, symptomatic chronic heart failure | 16 Jan 2026 |
Sertraline | Depression, panic disorder, obsessive compulsive disorder, post-traumatic stress disorder, social phobia, premenstrual dysphoric disorder | 6 Feb 2026 |
Metoprolol | Hypertension, angina pectoris | 6 Feb 2026 |
Betahistine | Meniere’s syndrome / disease, vestibular / peripheral vertigo | 9 Mar 2026 |
Methylphenidate | Attention deficit hyperactivity disorder, narcolepsy | 19 Mar 2026 |
