FDA Taking Steps on Rifampin, Rifapentine Shortages

FDA says it 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 to avoid shortages while the companies work to reduce or eliminate the impurities. An agency drug safety statement says FDA recently became aware of nitrosamine impurities in certain samples of rifampin and rifapentine.

The notice directs manufacturers to contact the CDER 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 says it will determine on a case-by-case basis whether the drugs should be released for distribution.

The post says the agency and manufacturers are investigating the origin of the impurities in the two drugs and FDA is developing testing methods for regulators and industry to detect MNP and CPNP in the medicines.