Antibiotic Treatment
This approach seeks to attack the bacterial overgrowth head on and fairly quickly with antibiotic drugs (Abx). It is the first choice for most gastroenterologists. It must be followed with preventative measures. Dose finding studies have achieved up to 91% success in eradicating SIBO (measured by hydrogen breath test) and 94% symptom improvement.
Which ones are used?
The primary antibiotics used are Rifaximin (Xifaxan) and Neomycin. They are almost completely non-absorbable which means they stay in the intestines, having a local action and don't cause systemic side effects, such as urinary tract infections. They are chosen specifically for this property which allows them to act only where they are needed. Metronidazole, a systemic antibiotic, is also used.
Which ones are used?
The primary antibiotics used are Rifaximin (Xifaxan) and Neomycin. They are almost completely non-absorbable which means they stay in the intestines, having a local action and don't cause systemic side effects, such as urinary tract infections. They are chosen specifically for this property which allows them to act only where they are needed. Metronidazole, a systemic antibiotic, is also used.
SIBO Antibiotic Doses
The following information is provided for physicians, based on the most recent dose finding studies and clinical expertise of Drs Scarpellini, Pimentel, Lombardo, Furnari and their teams. Many thanks for all their excellent, tireless work.
Rifaximin Dose Options:
1) 1600 mg per day x 10 days- 70-85% success normalizing LBT, 82% success normalizing GBT (Scarpellini)
1650 mg per day x 14 days (Pimentel), 550 mg tid.
2) 1200 mg per day x 14 days- 87-91% success normalizing GBT, 90-94% symptom improvement (Lombardo)
3) 1200 mg per day x 10 days with 5 g per day Partially Hydrolyzed Guar Gum
-87% success normalizing GBT, 91% symptom improvement (Furnari)
Rifaximin is available in both 200 mg and 550 mg in the US. Tid study doses are given at 8 am, 2 pm, 8 pm.
Rifaximin Pediatric Dosing:
1) 600mg per day x 7 days - 64% success normalizing LBT (Scarpellini)
2) 10-30mg/kg body weight, for IBD. 61% of cases had symptom relief. Higher dose had better pain relief. (Muniyappa)
Rifaximin + Neomycin Dosing:
Rifaximin 1600 mg per day + Neomycin 1000 mg per day x 10 days, 87% success normalizing LBT (Pimentel- this study used 1200 mg Rifaximin x 10 days but Dr Pimentel currently uses 1650 mg/day).
Neomycin is available in 500 mg in the US and is given bid (8 am and 8 pm or as fits one's schedule).
Rifaximin + Metronidazole Dosing:
Rifaximin 1600 mg per day + Metronidazole 750 mg per day x 10 days.
Metronidazole is available in 3 doses in the US (250 mg, 500 mg and 750 mg) and is usually given at 250 mg tid.
For more details, please see page 2 of my article SIBO: often ignored cause of IBS, my class videos and the other resources at Learning More.
- Rifaximin may be used for all cases of SIBO. There are 3 excellent dose options currently reported.
- Neomycin is effective for constipation cases and is used in addition to Rifaximin, as double Abx therapy. Metronidazole is an effective alternative to Neomycin, currently under study at Cedars-Sinai.
- If alternating diarrhea is present with constipation, the use of Rifaximin alone has been suggested.
Rifaximin Dose Options:
1) 1600 mg per day x 10 days- 70-85% success normalizing LBT, 82% success normalizing GBT (Scarpellini)
1650 mg per day x 14 days (Pimentel), 550 mg tid.
2) 1200 mg per day x 14 days- 87-91% success normalizing GBT, 90-94% symptom improvement (Lombardo)
3) 1200 mg per day x 10 days with 5 g per day Partially Hydrolyzed Guar Gum
-87% success normalizing GBT, 91% symptom improvement (Furnari)
Rifaximin is available in both 200 mg and 550 mg in the US. Tid study doses are given at 8 am, 2 pm, 8 pm.
Rifaximin Pediatric Dosing:
1) 600mg per day x 7 days - 64% success normalizing LBT (Scarpellini)
2) 10-30mg/kg body weight, for IBD. 61% of cases had symptom relief. Higher dose had better pain relief. (Muniyappa)
Rifaximin + Neomycin Dosing:
Rifaximin 1600 mg per day + Neomycin 1000 mg per day x 10 days, 87% success normalizing LBT (Pimentel- this study used 1200 mg Rifaximin x 10 days but Dr Pimentel currently uses 1650 mg/day).
Neomycin is available in 500 mg in the US and is given bid (8 am and 8 pm or as fits one's schedule).
Rifaximin + Metronidazole Dosing:
Rifaximin 1600 mg per day + Metronidazole 750 mg per day x 10 days.
Metronidazole is available in 3 doses in the US (250 mg, 500 mg and 750 mg) and is usually given at 250 mg tid.
For more details, please see page 2 of my article SIBO: often ignored cause of IBS, my class videos and the other resources at Learning More.
Site author: Dr Allison Siebecker