SIBO Antibiotic Treatment

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This approach seeks to attack the bacterial overgrowth head on and fairly quickly with pharmaceutical antibiotics, and has an excellent success rate: up to 91% SIBO eradication, and 94% symptom improvement.[1] It is the first choice for most gastroenterologists. Like all antibacterial SIBO treatments, it must be followed with preventative measures, since relapse is so common. The primary antibiotic, Rifaximin, is safe [2]  and has the unique property of helping improve the microbiome.[8] 

Which Antibiotics Are Used for SIBO?

Antibiotics are based on SIBO Type (gas type). Different antibiotics are needed to target the different bacteria and archaea (methanogens) that produce each type of gas. See specific protocols and doses by signing up here.
Primary:

• Rifaximin (Xifaxan) - used for hydrogen, as well as methane and hydrogen sulfide in combination with another antibiotic (listed below).[7] [12]
• Neomycin [3] or Metronidazole (Flagyl) [4] [5] [6] - used for methane, in combination with Rifaximin.
• Bismuth - used for hydrogen sulfide, alone or in combination with Rifaximin.[14] (Bismuth is a metal element with antibiotic properties. It is not a pharmaceutical antibiotic.)
  

Also used:

• Nitazoxanide (Alinia) - used for hydrogen, and for methane and hydrogen sulfide [13] in combination with Rifaximin.
  

Used less commonly (when the primary antibiotics can't be used): 

• Doxycycline - used for hydrogen  
• Amoxicillin/Clavulanic acid (Augmentin) - used for hydrogen; methane; and hydrogen sulfide in combination with bismuth
• Trimethoprim/Sulfamethoxazole (Bactrim) - used for hydrogen; and hydrogen sulfide in combination with bismuth​​

Rifaximin (Xifaxan) and Neomycin are almost completely non-absorbable, which means they stay in the intestines, having a local action and don't tend to cause systemic side effects, such as urinary tract infections. This property allows them to act right in the intestines where they are needed for SIBO.[17] [18]

Rifaximin (Xifaxan) is especially unique because it does not harm the microbiome and actually helps it (it increases lactobacillus, bifidus and faecalibacterium) and has many other benefits, including being anti-inflammatory, reducing LPS/endotoxin, increasing glutamine (which protects against leaky gut), and even prevents the antibiotic resistance of neomycin.[8] [9] [10] Rifaximin can be expensive, thus many turn to Canadian, Indian or compounding pharmacies or work with company representatives for less expensive options. For a list of studied alternative antibiotics to rifaximin for SIBO, see my Rifaximin Alternatives Handout. or consider the secondary options above. 

Clinically, Metronidazole and Nitazoxanide show effectiveness against methanogens, ​and are also anti-parasitics. Nitazoxanide also has effect against some hydrogen sulfide bacteria.[13]

Bismuth, while not a pharmaceutical antibiotic, is the primary antibacterial used for hydrogen sulfide, and in Thiol form, is also anti-biofilm, according to Dr. Paul Anderson, who pioneered bismuth-thiol formulas.

Antibiotics can disrupt the microbiome (Rifaximin/Xifaxan excepted). Probiotics are often taken with antibiotics to prevent yeast overgrowth and microbiome disruption. Studied options for this include: Culturelle Health and Wellness and Florastor, taken during antibiotics, and for 6 weeks after.[11] 

SIBO Antibiotic Duration

A standard treatment round of pharmaceutical antibiotics is 2 weeks. If hydrogen or methane gas is high (≥ 70 ppm), a 3 week course is sometimes used. 

Most cases need 2-5 treatment rounds of antibiotics or herbal antibiotics to clear SIBO (elemental diet typically requires less rounds). Retesting is used to determine if/when more rounds are needed, based on gas ppm levels. Unfortunately, extending antibiotic treatment for a longer duration to avoid the need for multiple rounds, often proves ineffective, as effect tends to peter out after 3 weeks in many cases. 

Symptom relief varies individually: many feel better within days of starting antibiotics, but it can take until the second or third round for others.  ​

See Treatment Overview for more info. 

Antibiotic Protocols and Dosage

Specifics are not displayed publicly on this website for legal purposes, but are available for free by signing up here.
(If you have already signed up: log in here)

SIBO Protocols & Doses - Sign up Here

Where to Get Bismuth

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While both bismuth and bismuth-thiol work for hydrogen sulfide, bismuth-thiol also works as an anti-biofilm.[14] [16]

- Bismuth Rx (prescription):

• Bismuth subnitrate or subcitrate is available from some compounding pharmacies in 650-750 mg/pill.

- Bismuth over-the counter: bismuth subsalicylate is available commercially over-the-counter

• Kaopectate (Amazon) (no sugar alcohols)
• Pepto Bismol (Amazon) (all forms, even pills, contain sugar alcohols which may aggravate SIBO symptoms - see Problematic Supplements for SIBO Handout)
• Various generics​

- Bismuth-Thiol Rx (prescription): available from some compounding pharmacies as

• 200 mg Bismuth Subnitrate / 100 mg Alpha Lipoic acid / 25 mg DMPS or 100 mg DMSA, per cap*[15]

- Bismuth-Thiol over-the counter:

• Priority One "Biofilm Phase-2 Advanced" (Amazon) or (exclusive pricing at Fullscript)*

*formulated by Dr. Paul Anderson - see his Bismuth-Thiol Handout 

Combination Dosing: Antibiotics + Herbal Antibiotics

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Antibiotics and Herbal Antibiotics can be combined (see Herbal Antibiotics and see specific protocols by signing up here, or log in here). For example, Allicin (Allimed/Allimax Pro) can be used with Rifaximin, in place of Neomycin or Metronidazole for Methane SIBO/Intestinal Methanogen Overgrowth.

FREE SIBO HANDOUTS

Antibiotic Alternatives
​to Rifaximin

SIBO Treatment: Pregnancy, Lactation,
​Pediatrics

Problematic Supplements
​For SIBO

For more details about antibiotics and SIBO treatments, see Dr. Siebecker's classes, join a Q&A and join Dr. Siebecker's newsletter.

More Resources: SIBO Antibiotic playlist on my YouTube  

   Learn more

SYMPTOMS TREATMENT SYMPTOM RELIEF HERBAL ANTIBIOTICS ELEMENTAL DIET SIBO DIET PREVENTING RELAPSE COURSES

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