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Generic name: rifamycin systemic

Brand names: Aemcolo

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Tablet Delayed Release, Oral:

Aemcolo: 194 mg


Mechanism of Action

Rifamycin inhibits bacterial synthesis by inhibiting the beta-subunit of the bacterial DNA-dependent RNA polymerase.



Feces: 86%

Protein Binding


Use: Labeled Indications

Travelers’ diarrhea: Treatment of travelers’ diarrhea (TD) caused by noninvasive strains of Escherichia coli in adults

Limitations of use: Rifamycin is not indicated in patients with diarrhea complicated by fever or bloody stool or due to pathogens other than noninvasive strains of E. coli.


Hypersensitivity to rifamycin, other rifamycin class antimicrobial agents (eg, rifaximin), or any component of the formulation.

Dosage and Administration

Dosing: Adult

Travelers' diarrhea: Oral: 388 mg twice daily for 3 days

Dosing: Geriatric

Refer to adult dosing.


Oral: Administer each dose with a 6 to 8 ounce glass of liquid (not alcohol), with or without food. Swallow tablets whole; do not crush, break, or chew.


Store at 20°C to 25°C (68°F to 77°F); excursions permitted to 15°C to 30°C (59°F to 86°F).

Drug Interactions

There are no known significant interactions.

Adverse Reactions

1% to 10%:

Central nervous system: Headache (3%)

Gastrointestinal: Constipation (4%), dyspepsia (<2%)

Frequency not defined:

Gastrointestinal: Abdominal pain

Miscellaneous: Fever


Concerns related to adverse effects:

  • Superinfection: Prolonged use may result in bacterial superinfection, including C. difficile infection (CDI); CDI has been observed >2 months postantibiotic treatment.

Other warnings/precautions:

  • Appropriate use: Not shown to be effective in patients with diarrhea complicated by fever and/or bloody stool; when these patients were treated with rifamycin, they had prolonged time to last unformed stool. Effectiveness has not been demonstrated in patients with travelers’ diarrhea caused by pathogens other than E. coli. Discontinue treatment and consider alternative antibacterial therapy if diarrhea worsens or persists >48 hours.

Monitoring Parameters

Bloody stools, frequency of diarrhea


Pregnancy Considerations

Maternal systemic absorption is limited following oral administration, therefore exposure to the fetus is not expected.

Patient Education

  • Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)
  • Patient may experience headache or constipation. Have patient report immediately to prescriber signs of Clostridioides (formerly Clostridium) difficile (C. diff)-associated diarrhea (abdominal pain or cramps, severe diarrhea or watery stools, or bloody stools) (HCAHPS).
  • Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for health care professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience, and judgment in diagnosing, treating, and advising patients.

Source: Wolters Kluwer Health. Last updated November 12, 2019.