You should talk with your healthcare provider prior to taking this medication if you have:
- Liver disease, such as hepatitis, cirrhosis, or liver failure
- Kidney disease, such as kidney failure (renal failure)
- Any of a group of rare medical conditions known as porphyria
- Any allergies, including to foods, dyes, or preservatives.
Also, let your healthcare provider know if you are:
- Pregnant or thinking of becoming pregnant (see Rifadin and Pregnancy)
- Breastfeeding (see Rifadin and Breastfeeding).
Make sure to tell your healthcare provider about all other medications you are taking, including prescription and nonprescription medicines, vitamins, and herbal supplements.
(Click Precautions and Warnings With Rifampin to learn more, including information on who should not use the drug.)
Rifampin works by blocking the action of an enzyme known as RNA polymerase. Bacteria need RNA polymerase to make RNA, a molecule that is important for transferring the bacteria's genetic information and making proteins. These actions are essential for the bacteria to survive. By blocking RNA polymerase, rifampin kills the bacteria.
Rifampin specifically blocks bacterial RNA polymerase. It does not affect human RNA polymerase and, therefore, does not interfere with the production of RNA in humans.