Rifamycin
Indications
Rifamycin is used for: 
 Traveler’s Diarrhea
                                              
                        Adult Dose
Traveler’s Diarrhea
Minimally absorbed antibiotic indicated for traveler’s diarrhea caused by noninvasive strains of Escherichia coli, not complicated by fever or blood in the stool
388 mg (2 tablets) PO BID x 3 days
Hepatic impairment: Not studied; no dosage adjustment required owing to minimal systemic absorption
                                              
                        Child Dose
<18 years: Safety and efficacy not established
                                              
                        Renal Dose
Renal impairment: Not studied; no dosage adjustment required owing to minimal systemic absorption
                                              
                        Administration
Take each dose with full glass of liquid (6-8 oz)
Do not take concomitantly with alcohol
May take with or without food
                                              
                        Contra Indications
Known hypersensitivity to rifamycin or any of the other rifamycin-class antimicrobial agents
                                              
                        Precautions
Not effective for diarrhea complicated by fever and/or bloody stool; discontinue use if diarrhea gets worse or persists >48 hr; consider alternative antibacterial therapy
Consider Clostridium difficile-associated diarrhea (CDAD) in all patients who present with diarrhea following antibacterial drug use; CDAD can occur over 2 months after antibiotic discontinued
Prescribing rifamycin without proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to the patient and increases the risk of the development of drug-resistant bacteria
Owing to minimal systemic rifamycin concentrations observed, clinically relevant drug interactions are not expected
                                              
                        Pregnancy-Lactation
Pregnancy
There are no available data regarding use in pregnant women
Systemic absorption in humans is negligible following PO administration; not expected that maternal use results in fetal exposure
Lactation
There are no available data regarding presence in human milk
Systemic absorption in humans is negligible following PO administration; exposure to breastfed infants through breastmilk is expected to be negligible
The development and health benefits of breastfeeding should be considered along with the mother’s clinical need for the drug and any potential adverse effects on the breastfed child or from the underlying maternal condition
                                              
                        Interactions
Side Effects
Side effects of Rifamycin : 
 1-10%
Constipation (3.5%)
Headache (3.3%)
Dyspepsia (<2%)
                                              
                        Mode of Action
Oral nonabsorbable antibiotic that can be used for the treatment of bacterial infections of the colon
Belongs to the ansamycin antibacterial drug class and acts by inhibiting the beta-subunit of bacterial DNA-dependent RNA polymerase, blocking 1 of the DNA transcription steps; this results in bacterial synthesis inhibition and consequently bacterial growth