A medication used to treat traveler's diarrhea.


An antibacterial used to treat traveler's diarrhea.


Rifamycin is the prime member of the rifamycin family which are represented by drugs that are a product of fermentation from the gram-positive bacterium _Amycolatopsis mediterranei_, also known as _Streptomyces mediterranei_. The parent compound of rifamycin was rifamycin B which was originally obtained as a main product in the presence of diethylbarburitic acid. Some small modifications where performed in this inactive compound and with the creation of rifamycin SV there was the first antibiotic used intravenously for the treatment of tuberculosis.[2]

Rifamycin has had several direct derivative products such as rifamycin SV, rifaximin, rifampin and rifamycin CV. All of the derivatives have slight different physicochemical properties when compared to the parent structure.[1]

Rifamycin was further developed by Cosmo Technologies Ltd and approved in November 16, 2018 by the FDA as a prescription drug after being granted the designation of Qualified Infectious Disease Product which allowed it to have a status a priority review.[Read more



Rifamycin is indicated for the treatment of adult patients with travelers' diarrhea caused by noninvasive strains of _E. coli_. The status of the disease should not be complicated by fever or blood in the stool. To prevent drug-resistant bacteria, it is important to mention that the use of rifamycin... Read more


Rifamycin is known to be effective against Gram-positive and Gram-negative pathogens and mycobacteria. It is very effective against _E. coli_ reporting a MIC90 of 64-128 mcg/ml without showing cross-resistance with other antimicrobial agents.[ Read more

Mechanism of action

Rifamycins, as well as all the other members of this group, present an antibacterial mechanism of action related to the inhibition of RNA synthesis. This mechanism of action is done by the strong binding to the DNA-dependent RNA polymerase of prokaryotes. The inhibition of the RNA synthesis is thoug... Read more


Rifamycin has a very poor absorption[4] and thus, the ge... Read more

Protein binding

The protein binding of rifamycin is of about 80-95%.[... Read more

Volume of distribution

The reported volume of distribution after measured after a dosage of 250 mg of rifamycin is 101.8 L.[ Read more


The reported clearance when a dose of 250 mg of rifamycin was administered is 23.3 L/h.[ Read more

Half life

The reported half-life when a dose of 250 mg of rifamycin was administered is 3 h.[ Read more

Route of elimination

From the administered dose, 18%, 50% and 21% is recovered in feces during the first 24, 48 and 72h after administration. This will represent about 90% of the administered dose eliminated by the feces while the urinary secretion is negligible.[ Read more


In safety studies with rifamycin, it was reported a potential of hepatotoxicity due to the depletion of glutathione and the generation of reactive oxygen species in liver microsomes. It is important to mention that this effect is mainly observed in the intravenous administration as the oral dosage d... Read more

Adverse Effects

Effect Regions Age Groups Incidences Evidence Type
Constipation US
  • Kind: experimental
    • Percent: 3.5
  • Kind: placebo
    • Percent: 1.5
  • Clinical Trial
    Headache US
  • Kind: experimental
    • Percent: 3.3
  • Kind: comparator
    • Percent: 1.9
  • Clinical Trial
    Abdominal pain/discomfort US
  • Kind: experimental
    • Percent: 0.5
  • Clinical Trial
    Pyrexia US
  • Kind: experimental
    • Percent: 0.3
  • Clinical Trial


    • Hypersensitivity:
      • true
    • Regions: US

    Food Interactions

    Avoid alcohol.

    Take with a full glass of water.

    Take with or without food.