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# FDA Continuing Rifampin/Rifapentine Products Analysis
- URL: https://www.fdaweb.com/fda-continuing-rifampin-rifapentine-products-analysis/
- Published: 2021-01-28T12:00:00.000Z
- Updated: 2026-09-14T16:44:28.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5148548

FDA says it is continuing to investigate the presence of 1-methyl-4-nitrosopiperazine (MNP) in rifampin or 1-cyclopentyl-4-nitrosopiperazine (CPNP) in rifapentine approved for sale in the U.S. An agency [statement](https://www.fda.gov/drugs/drug-safety-and-availability/laboratory-analysis-rifampinrifapentine-products?ref=fdaweb.com) says both antibacterial drugs are used to treat tuberculosis and rifampin also is used to treat or prevent other serious infections.

The notice says the acceptable intake limits are 0.16 parts per million (ppm) for MNP in rifampin and 0.1 ppm for CPNP in rifapentine. The statement includes a table of laboratory results showing MNP in rifampin or CPNP in rifapentine products the agency tested.

To maintain a supply of these products to patients, FDA says it will not object to manufacturers distributing rifampin containing MNP below 5 ppm or temporarily distributing rifapentine containing CPNP below 20 ppm.