其 他 安 全 警 示
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| The United States: FDA works to mitigate shortages of rifampin and rifapentine after manufacturers find nitrosamine impurities (English only) |
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The US Food and Drug Administration (FDA) announces that it recently became aware of nitrosamine impurities in certain samples of rifampin and rifapentine. These are antibacterial drugs used to treat tuberculosis; rifampin is also used to treat other serious infections. Patients taking rifampin or rifapentine should continue taking their current medicine and consult with their health care professional about any concerns.
To mitigate or avoid shortages and to help ensure patients have access to these necessary medicines, FDA will not object to certain manufacturers temporarily distributing rifampin containing 1-methyl-4-nitrosopiperazine (MNP) or rifapentine containing 1-cyclopentyl-4-nitrosopiperazine (CPNP) above the acceptable intake limits until they can reduce or eliminate the impurities.
The acceptable intake limits are 0.16 parts per million (ppm) for MNP in rifampin and 0.1 ppm for CPNP in rifapentine. The agency will not object to certain manufacturers temporarily distributing rifampin containing MNP below 5 parts per million (ppm). The agency also will not object to certain manufacturers temporarily distributing rifapentine containing CPNP below 14 ppm. FDA will not object to these higher exposures to maintain patient access to these life-saving medications.
Manufacturers should contact the Center for Drug Evaluation and Research’s Drug Shortages Staff when their testing of rifampin or rifapentine shows levels of nitrosamines that exceed the acceptable intake limits of 0.16 ppm for MNP and 0.1 ppm for CPNP. FDA will determine on a case-by-case basis whether those drugs should be released for distribution.
FDA and manufacturers are investigating the origin of these impurities in rifampin and rifapentine, and the agency is developing testing methods for regulators and industry to detect MNP and CPNP in these medicines. FDA continues its ongoing review, surveillance, compliance and pharmaceutical quality efforts across every product area and will continue to work with drug manufacturers to ensure safe, effective and high-quality drugs for the American public.
MNP and CPNP belong to the nitrosamine class of compounds, some of which are classified as probable or possible human carcinogens (substances that could cause cancer), based on laboratory tests such as rodent carcinogenicity studies. Although there are no data available to directly evaluate the carcinogenic potential of MNP and CPNP, information available on closely related nitrosamine compounds was used to calculate lifetime exposure limits for MNP and CPNP.
Tuberculosis is a potentially deadly disease that affects the lungs and sometimes other parts of the body, and the risk of not taking the medicine outweighs any potential risk from MNP or CPNP. Patients taking rifampin for other conditions should discuss with their health care professional whether they can use an alternative medicine.
Please refer to the following website in FDA for details:
http://www.fda.gov/drugs/drug-safety-and-availability/fda-works-mitigate-shortages-rifampin-and-rifapentine-after-manufacturers-find-nitrosamine
In Hong Kong, there are 28 registered pharmaceutical products containing rifampicin (also known as rifampin). There is only one registered pharmaceutical product containing rifapentine, namely Priftin Tablets 150mg (HK-65512), which is registered by Sanofi Hong Kong Limited. All products are prescription-only medicines.
So far, the Department of Health (DH) has received 22 cases of adverse drug reaction related to rifampicin. None of them is concluded to be related to the presence of 1-methyl-4-nitrosopiperazine (MNP). The DH has not received any case of adverse drug reaction related to rifapentine.
The DH has been contacting the certificate holders of all registered rifampicin and rifapentine products for follow up on the impact of the local marketed products; and will remain vigilant on the development of the issue and any safety update of the drugs issued by overseas drug regulatory authorities for consideration of any action deemed necessary.
Patients who are taking rifampicin- and rifapentine-containing products should not stop taking the medicines unless advised by their prescribers.
Ends/Thursday, Aug 27, 2020
Issued at HKT 18:00
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