Rifaximin Medications

Rifaximin is a gut-specific antibiotic used to treat traveler's diarrhea, irritable bowel syndrome with diarrhea, and to prevent hepatic encephalopathy complications.

Xifaxan

Rifaximin

$0.71 per pill

200 | 400 | 550mg

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About Rifaximin

Rifaximin is a gut-targeted antibiotic belonging to the rifamycin class. It is approved in Australia for the treatment of traveller’s diarrhoea and for the prevention of recurrent hepatic encephalopathy. The drug is also licensed in the United States and Europe for irritable bowel syndrome with diarrhoea (IBS-D). By binding to the β-subunit of bacterial DNA-dependent RNA polymerase, rifaximin blocks bacterial protein synthesis while remaining largely confined to the intestinal lumen, which limits systemic exposure. Brand names such as Xifaxan and Rifamate are widely recognised, and generic rifaximin tablets are available through our online pharmacy at a lower cost. Off-label, clinicians sometimes prescribe rifaximin for small-intestinal bacterial overgrowth (SIBO) and certain cases of Clostridioides difficile infection, although these uses are not formally approved by the Therapeutic Goods Administration (TGA). The drug’s narrow spectrum, minimal absorption, and favourable safety profile have made it a common choice for conditions where a local antibacterial effect is desired.

What is rifaximin?

Rifaximin is a non-systemic, broad-spectrum antibiotic of the rifamycin family. The TGA first approved it in 2004 for traveller’s diarrhoea caused by Escherichia coli and, in 2015, extended the indication to secondary prophylaxis of hepatic encephalopathy in patients with cirrhosis. In the United States, the FDA added IBS-D to the label in 2015, and the European Medicines Agency granted a similar extension in 2016. The core molecular action involves reversible binding to the β-subunit of bacterial DNA-dependent RNA polymerase, which halts transcription and ultimately kills susceptible bacteria. Because it is poorly absorbed (<0.5 % of the dose reaches the systemic circulation), rifaximin exerts its effect primarily within the gastrointestinal tract. Both branded (e.g., Xifaxan) and generic tablets are stocked by our service, offering flexible options for patients who need a robust intestinal antibiotic without widespread systemic exposure.

How rifaximin works

Mechanism of Action

Rifaximin penetrates the bacterial cell wall and attaches to the RNA polymerase β-subunit, inhibiting the initiation of mRNA synthesis. This interruption of transcription prevents the production of essential proteins, leading to bacterial cell death. The drug’s high affinity for bacterial enzymes, combined with its negligible plasma concentrations, ensures that the antimicrobial activity stays localized to the gut lumen.

Therapeutic Effects

By eradicating pathogenic gram-negative and some gram-positive organisms, rifaximin reduces intestinal bacterial overgrowth, diminishes toxin production, and restores a healthier microbiome balance. In hepatic encephalopathy, decreasing ammonia-producing gut bacteria translates into lower systemic ammonia levels, which improves neurocognitive function. For traveller’s diarrhoea, the rapid elimination of E. coli and related pathogens shortens the duration of loose stools and abdominal cramping.

Onset and Duration

Clinical trials show that symptom relief in traveller’s diarrhoea often begins within 24-48 hours of the first 200 mg dose taken three times daily. In hepatic encephalopathy, significant reductions in ammonia concentrations are observed after five days of twice-daily 550 mg dosing, with continued benefit as long as therapy is maintained. The drug’s half-life in the gut is approximately 4-6 hours, supporting twice-daily dosing for chronic indications.

Approved uses and applications

Approved indications

Traveller’s diarrhoea: 200 mg taken three times daily for three days, as recommended by the TGA and the Australian Therapeutic Guidelines.
Secondary prophylaxis of hepatic encephalopathy: 550 mg taken twice daily, shown in the Phase III HELP trial (published in The New England Journal of Medicine) to reduce the risk of recurrence by 58 % compared with placebo.

These approvals are based on robust randomized controlled trials and are reflected in the product labeling of both the branded and generic formulations.

Off-label uses

Rifaximin is sometimes employed off-label for small-intestinal bacterial overgrowth (SIBO) and for the adjunctive treatment of Clostridioides difficile infection when standard therapy fails. Although several small studies published in Gut and Alimentary Pharmacology & Therapeutics suggest symptom improvement in SIBO, the TGA has not granted formal approval for this indication. Clinicians should discuss the evidential limits with patients before initiating off-label therapy.

Clinical efficacy

In the pivotal IBS-D study (published in Lancet Gastroenterology & Hepatology), 56 % of participants receiving rifaximin 550 mg twice daily for two weeks reported significant relief of abdominal pain and stool consistency, versus 42 % on placebo (p < .001). For traveller’s diarrhoea, a meta-analysis in Clinical Infectious Diseases demonstrated a 68 % clinical cure rate within 72 hours of treatment, compared with 44 % for placebo. These data underscore rifaximin’s rapid and reliable effect when used for its approved purposes.

Buying rifaximin from our online pharmacy

Why choose our service

Our online pharmacy bridges the gap for Australians who encounter supply shortages or high out-of-pocket costs for gut-focused antibiotics. By ordering through a secure, regulated portal, patients receive verified medication without the delays typical of traditional brick-and-mortar pharmacies. Privacy is maintained through discreet packaging, and a dedicated support team answers any logistics questions promptly.

Brand names and generic options

Xifaxan® (brand, 200 mg and 550 mg tablets)
Rifamate® (brand, 200 mg tablets)
Generic rifaximin (identical 200 mg and 550 mg strengths)

Our service lists the brand products for those who prefer a familiar name, while the generic version provides a cost-saving alternative-often up to 40 % less per tablet. Prices are updated weekly to stay competitive with Australian pharmacy chains.

Quality & safety

We partner exclusively with licensed international pharmacies that comply with WHO Good Manufacturing Practice (GMP) standards and hold approval from the TGA’s listed-manufacturer program. Every batch undergoes third-party testing for potency, purity, and dissolution.

Pricing & access

Standard 200 mg pack (30 tablets): AUD 38 (generic) vs. AUD 65 (brand)
Standard 550 mg pack (30 tablets): AUD 78 (generic) vs. AUD 135 (brand)

All returning customers enjoy a 10 % lifetime discount on reorders, making long-term therapy more affordable.

Discreet delivery

Orders ship via express courier in approximately 7 days, or via standard postal service within 3 weeks. Packages are unmarked, sealed in tamper-evident envelopes to protect privacy.

Dosing, formulations & administration

Available formulations

Rifaximin is supplied as oral tablets in two strengths: 200 mg and 550 mg. No liquid or injectable forms are marketed for human use.

Typical dosing ranges

Traveller’s diarrhoea: 200 mg three times daily for three days.
Hepatic encephalopathy prophylaxis: 550 mg twice daily, indefinite treatment as directed by a clinician.
Off-label SIBO: clinicians often prescribe 550 mg twice daily for 14 days, though this regimen is not officially sanctioned.

These figures represent common clinical practice; the exact dose must be individualized by a qualified healthcare provider based on disease severity, renal or hepatic function, and concomitant medications.

Administration guidelines

Rifaximin tablets should be swallowed whole with a full glass of water. Food does not significantly affect absorption, so the medication can be taken with or without meals. For hepatic encephalopathy adherence to the twice-daily schedule (e.g., morning and evening) helps maintain steady gut concentrations. Patients should avoid crushing or chewing tablets, as this may reduce efficacy.

The precise regimen for any patient must be determined by a healthcare professional.

Safety profile & considerations

Common side effects

Nausea: reported in 8-12 % of users.
Headache: observed in 6-9 % of participants.
Abdominal discomfort: occurs in 4-7 % of cases.
Flatulence: noted in 5-8 % of trials.
Fatigue: reported less frequently (<5 %).

These events are typically mild and resolve without intervention.

Serious adverse events

Rare but serious reactions include severe hypersensitivity (rash, angioedema) and Clostridioides difficile infection. The latter has been documented in <0.5 % of patients receiving prolonged courses; clinicians should monitor for watery diarrhea and abdominal pain that persists after treatment.

Contraindications

Known hypersensitivity to rifaximin or any rifamycin derivative.
Acute liver failure (due to potential accumulation).
Pregnant or breastfeeding women should only use the drug if the benefit outweighs the risk, as safety data are limited.

Drug interactions

Rifaximin exhibits minimal systemic interaction because of its low plasma levels. However, it can induce the intestinal expression of P-glycoprotein transporters, potentially reducing the absorption of certain oral drugs such as cyclosporine and digoxin. Caution is advised when co-administered with strong CYP3A4 inhibitors (e.g., ketoconazole) or in patients taking multiple antibiotics, to avoid additive gut flora disruption.

Special populations

Pregnancy & lactation: Animal studies show no teratogenic effect, but human data are insufficient; discuss risks with a prenatal care provider.
Elderly: Age-related changes in gut motility do not markedly affect rifaximin exposure, but monitoring for constipation or dehydration is prudent.
Renal or hepatic impairment: No dose adjustment is required for mild to moderate impairment; severe hepatic dysfunction is a contraindication.

Always consult a qualified professional before initiating therapy.

Frequently asked questions

What is the difference between rifaximin and metronidazole for traveller’s diarrhoea? Rifaximin remains in the intestine and targets a broader range of gram-negative bacteria, while metronidazole is absorbed systemically and is more active against anaerobes. Clinical trials show faster symptom resolution with rifaximin and fewer systemic side effects.
How long does rifaximin take to work for hepatic encephalopathy? Patients often notice improved mental clarity within five days of starting the twice-daily 550 mg regimen, with continued benefit as long as the medication is maintained.
Can I take rifaximin with antacids? Antacids do not significantly affect the drug’s gut concentration, so co-administration is generally safe. Nonetheless, discuss all over-the-counter products with your clinician.
What should I do if I develop a rash while on rifaximin? Stop the medication immediately and seek urgent medical evaluation; a rash may signal a hypersensitivity reaction that requires alternative treatment.
Is rifaximin safe for long-term use in hepatic encephalopathy? Long-term studies up to 12 months have demonstrated sustained efficacy and a low incidence of serious adverse events, but regular liver function monitoring is recommended.
Does food affect the absorption of rifaximin? Food has minimal impact; the drug can be taken with meals or on an empty stomach without compromising its antimicrobial action.
Can rifaximin cause antibiotic resistance? Because systemic exposure is low, the risk of selecting resistant organisms outside the gut is reduced. However, resistance among intestinal flora has been reported after repeated courses, underscoring the need for clinician-guided treatment intervals.
What information should I provide my doctor when discussing rifaximin?
- Complete list of current medications, including supplements and over-the-counter products.
- History of liver disease, kidney function, and any prior antibiotic reactions.
- Specific symptoms you are experiencing and their duration.
- Any recent travel or exposure to contaminated food/water.

Disclaimer

The information provided about rifaximin is for general knowledge only. It does not replace professional medical consultation or the official prescribing information for medications containing this ingredient. All treatment decisions, including dosing, formulation selection, and monitoring, should be made under the supervision of a qualified healthcare provider who can assess individual medical history, current medications, and specific health needs. We assume all readers are responsible adults capable of making informed decisions about their health. Our online pharmacy offers access to medications containing rifaximin for individuals who may have limited availability through traditional pharmacies, prescription-based insurance schemes, or who are seeking affordable generic alternatives. Always consult your doctor before starting, changing, or discontinuing any medication containing rifaximin.