What should I know about nitrosamines in my medication?

Medication Information Leaflet

I have been informed that my medication contains nitrosamine impurities. What are nitrosamines? 

Nitrosamines are chemical substances that are present in our daily lives. They can be found in low levels in our water and foods, including dairy products such as milk and cheese, processed meat such as sausages, pickled vegetables and salted fish. 

Why are they found in my medication?

Nitrosamines impurities can be formed in certain medications when the medication is being produced. When nitrosamines are taken below levels that are considered acceptable by healthcare regulatory agencies, it is not expected to cause any harm.

What is the concern of possible nitrosamine impurities in my medication? 

In animal studies, nitrosamine impurities have been found to cause cancer and therefore it has been identified as a potential carcinogen in humans. A carcinogen is a substance that is capable of causing cancer in humans. However, in these studies, the amount of nitrosamine impurities given to the animals were much higher than what we would normally be exposed to. People taking the drugs that contain nitrosamine impurities at, or below the acceptable level every day for 70 years are not expected to have an increased risk of cancer.  

How to know if my medication contains nitrosamines?

The presence of nitrosamine impurities in some medications have only been found out recently. Regulatory authorities regularly review the presence of nitrosamine in medications and whether they are at a level that may cause harm to humans. If nitrosamine impurities are found in the medication, regulatory authorities such as the Singapore Health Sciences Authority(HSA) will advise the healthcare professionals on the appropriate actions required to protect you.

If you have any questions about your medication, or want to find out more, please discuss with your healthcare professional.  

My medication may contain nitrosamine impurities, but I am advised to continue taking them. What should I do?

There are no immediate health risks associated with the use of medication containing low levels of nitrosamine impurities.  Please continue taking the medication as directed by your healthcare professional. 

HSA and other health regulatory bodies will decide whether the level of nitrosamines is acceptable and the appropriate actions to be taken. The risk related to taking medications with nitrosamine impurities may depend on several factors such as
  • The daily dose of the medication
  • The duration of your treatment
  • The level of nitrosamine impurities
  • Whether different treatment choices are available
HSA and other health regulatory bodies will also balance the risk of you continuing to take medications with nitrosamine impurities against the need to make sure you continue to have medications available to treat your condition. 

My medication has been recalled due to the presence of nitrosamine impurities, what should I do?  

If your medication has been recalled, please continue taking your medication until you have been provided with a replacement brand. In some situations, your doctor might choose a different medication to treat you. There is no immediate safety risk to continue taking the medication. 

Do not stop taking your medication suddenly as this can possibly be dangerous, and may cause greater harm.

What precautions should I take?

 You should continue taking your medication as directed by your doctor. 

If there are nitrosamine impurities found in your medication at unacceptable levels, you will be informed by your healthcare professional.   Your healthcare professional will then advise you on what you need to do and whether there are suitable replacements available. 

If you take more than the recommended dose, please seek medical advice immediately. The information provided on this page does not replace information from your healthcare professional. Please consult your healthcare professional for more information.

This article is jointly developed by members of the National Medication Information workgroup. The workgroup consists of cluster partners (National Healthcare Group, National University Health System and SingHealth), community pharmacies (Guardian, Unity and Watsons) and Pharmaceutical Society of Singapore. The content does not reflect drug availability and supply information in pharmacies and healthcare institutions. You are advised to check with the respective institutions for such information.

Last updated on Nov 2021
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