The Therapeutic Goods Administration (TGA) is investigating potential contamination of rifampicin medicines with very low levels of the nitrosamine impurity, 1-methyl-4-nitrosopiperazine (MeNP or MNP).
Rifampicin, marketed in Australia as Rifadin and Rimycin, is an antibiotic prescription medicine. Rifampicin is an essential, first-line medicine for the treatment of tuberculosis. Rifampicin is also used to treat or prevent other serious infections including blood infections and leprosy.
Australian sponsors of rifampicin products have reported that all rifampicin products in the Australian market contain traces of MeNP. This issue also affects rifampicin products supplied internationally.
Consumers are strongly advised to continue to take their rifampicin medicines as prescribed. It is critical that patients do not stop taking their rifampicin medicines unless instructed to by their health professional.
What is MeNP?
MeNP is a type of nitrosamine that is present as an impurity. Nitrosamines are a group of compounds which can damage DNA. They are commonly found in low levels in a variety of foods, including smoked and cured meats, dairy products, vegetables, in some drinking water, and in air pollution. Long-term exposure, over years, can increase an individual's risk of developing cancer.
The additional risk that would be posed by the trace levels of MeNP being detected in rifampicin is likely to be very low. However, the presence of nitrosamine impurities is generally considered unacceptable for a medicine. The actual health risk depends on the medicine and dose taken and will vary from person to person.
Nitrosamine impurities have also been found in other medicines. They were first identified in 'sartan' medicines in 2018. Medicines affected by nitrosamine impurities in Australia include 'sartan' blood pressure medicines in 2018, metformin and ranitidine products in 2019, and varenicline products in 2021.
What should consumers do?
There is no immediate health risk from this issue. If you take rifampicin, do not stop your treatment without first consulting a doctor or pharmacist.
Tuberculosis is a potentially life-threatening disease. The risk of not taking the medicine outweighs any potential risk from MeNP.
If you have any other questions or concerns about this issue, you should speak to your health professional.
What should health professionals do?
Please be aware that MeNP is present at very low levels in rifampicin products supplied in Australia. However, there is no reason to stop prescribing rifampicin as the benefits continue to far outweigh the risk posed by this impurity.
You may wish to remind patients of the importance of treating tuberculosis and to continue taking their medicines in line with the instructions in the Product Information. Patients should be reassured that that the risks posed by MeNP at the trace levels observed overseas are considered very low.
What is the TGA doing?
The TGA has reviewed results reported by sponsors of rifampicin medicines on the ARTG. We continue to work with our international regulatory partners and rifampicin sponsors to respond to this issue.
Consistent with international regulatory approaches including in Europe and the Unites States, the TGA is allowing sponsors to supply rifampicin products with trace amounts of MeNP to the Australian market to ensure that patients have continued access to this essential medicine.
The TGA is requiring sponsors to investigate this issue and will determine whether other regulatory actions are required. We are also working with sponsors to oversee the implementation of improved manufacturing and testing processes that will ensure that rifampicin medicines supplied in Australia meet our high standards for quality.
Consumers and health professionals can report problems with medicines or vaccines. The reports will contribute to the TGA's product monitoring.
The TGA cannot give advice about an individual's medical condition. Consumers are strongly encouraged to talk with a health professional if they are concerned about a possible adverse event associated with a medicine or vaccine.