Xifaxan (Rifaximin) — Patient-Friendly Medicine Information (Australia)

Xifaxan contains the active ingredient rifaximin. It is an antibiotic designed to act mainly within the gut. This guide explains how it works, when it’s used, how to take it, what to expect, and important safety considerations for people in Australia.

Always follow the advice provided by your healthcare professional. If you have questions about your condition or treatment, speak with a pharmacist or prescriber.

Basic product information

How rifaximin works (mechanism of action)

Rifaximin is an antibiotic that works by targeting bacterial DNA synthesis. It binds to bacterial DNA-dependent RNA polymerase, reducing the ability of susceptible bacteria to reproduce. Because rifaximin has very low systemic absorption, it primarily acts within the intestines, aiming to reduce harmful gut bacteria while limiting effects throughout the rest of the body.

Unlike some antibiotics that may strongly disrupt the entire body’s microbiome, rifaximin is often described as having a “local” effect in the gut. This may contribute to a lower risk of certain systemic antibiotic-related side effects (though it still can affect gut flora).

Pharmacokinetics (how the body handles it)

Absorption

Rifaximin is minimally absorbed from the gastrointestinal tract. Most of the medicine remains in the gut lumen where it can exert its antibacterial action.

Distribution

Because systemic absorption is low, circulating drug levels in the bloodstream are typically very small.

Metabolism

Rifaximin is not extensively metabolised systemically due to its low absorption.

Excretion

The drug is largely eliminated via the faeces (with very little in the urine).

Practical takeaway: For many patients, rifaximin’s low whole-body absorption means fewer systemic drug interactions than antibiotics that circulate widely in the body. However, interactions can still occur, and it’s important to review your current medicines.

What it’s typically used for

Xifaxan (rifaximin) is used for specific conditions where gut bacteria are believed to play a role, and in certain liver-related complications. The exact indication and schedule depend on your diagnosis.

Common indications in clinical practice

• Hepatic encephalopathy (a condition related to liver disease, where changes in brain function can occur). Rifaximin is used in certain scenarios to help reduce episodes of encephalopathy.
• Diarrhoea associated with gastrointestinal conditions (for example, travellers’ diarrhoea or other conditions determined by your healthcare team). Use depends on local clinical guidance, diagnosis, and susceptibility patterns.
• Possible role in irritable bowel syndrome (IBS) with diarrhoea in some treatment pathways, where a gut-directed approach is considered. (Eligibility and availability can vary.)

Note: Indications and approved uses can differ by country and by product listing. In Australia, your healthcare professional will align treatment with the relevant product information and local guidelines.

Dosing and timing

Dosing schedules for rifaximin depend on the condition being treated, your kidney/liver status, and the planned treatment course. Your pharmacist or prescriber will provide the exact instructions.

Typical approach (general guidance)

• Finish the full course unless advised otherwise.
• Take tablets at consistent times each day if you are on a multi-day regimen.
• Swallow whole with water unless your medicine label states otherwise.

Timing with meals

Rifaximin is generally taken with or without food. Many people find it easiest to take with meals to reduce stomach upset. If your product label provides specific instructions, follow those.

If you miss a dose, take it when you remember unless it’s nearly time for the next dose. Don’t take a double dose to make up for a missed one.

Food interactions and gastrointestinal comfort

Because rifaximin acts locally in the intestines and is minimally absorbed, the main “interaction” with food is about how comfortable it is for you to take the medicine.

What to consider

• Take with meals if you get nausea. Some people tolerate antibiotics better with food.
• Stay hydrated, especially if you are taking rifaximin for diarrhoea-related issues.
• Avoid drastic dietary changes during treatment unless your healthcare professional recommends it.

If you are on a diet for liver disease or gut conditions, keep to that plan and discuss any special dietary instructions with your healthcare professional.

Alcohol interactions

Rifaximin is not known for a direct, classic “alcohol-antibiotic” reaction like some older medicines. However, it’s still important to consider how alcohol may affect your underlying condition.

Why alcohol may matter

• If you have liver disease or hepatic encephalopathy, alcohol can worsen liver function and increase the risk of confusion, sleep changes, and other symptoms.
• If you are being treated for diarrhoea, alcohol may worsen dehydration, irritation, and recovery.

Practical advice: Consider avoiding alcohol during treatment and seek personalised advice if you plan to drink.

Interactions with other medicines

Rifaximin’s low systemic absorption can mean fewer whole-body interactions than some antibiotics, but drug interactions are still possible. Always provide your pharmacist with a full list of your current medicines, including over-the-counter products and herbal supplements.

Examples of medicines that may require extra checking

• Strong inhibitors or inducers of certain drug transport pathways or enzymes (your pharmacist can check what applies to your situation).
• Medicines that affect gut motility or that are used for severe bowel symptoms may change the way you experience symptoms while on treatment.
• Other antibiotics or medications affecting gut flora—your clinician will decide whether they should be combined.

Important: Don’t start, stop, or change doses of any medicine without advice. If you feel you may have a medicine interaction, contact your pharmacist promptly.

Safety profile and side effects

Like all medicines, rifaximin can cause side effects. Many people tolerate it well, but you should know what’s normal and what requires urgent attention.

Common or expected side effects

• Nausea or mild stomach discomfort
• Abdominal pain or bloating
• Changes in bowel habits (including improvement of diarrhoea, but sometimes temporary changes)
• Headache
• Fatigue

Serious side effects — seek urgent help

Stop taking rifaximin and seek urgent medical help if you experience symptoms of a serious allergic reaction or severe complications, such as:

• Swelling of the face, lips, tongue, or throat
• Difficulty breathing or wheezing
• Severe rash or blistering skin reactions
• Severe or persistent watery diarrhoea, especially if accompanied by fever, abdominal cramping, or blood/mucus in stool (could indicate a serious gut infection)

Special populations

• Liver impairment: dosing decisions and monitoring may differ depending on the condition. Discuss your liver status.
• Kidney impairment: because systemic exposure is low, dose adjustment may not always be required, but individual advice matters.
• Pregnancy and breastfeeding: discuss risks and benefits with your healthcare professional.
• Older adults: generally tolerated, but always report new or worsening symptoms promptly.

Practical use tips (making treatment easier)

• Use a reminder: If you’re on multiple daily doses, set phone alerts to help you stay consistent.
• Hydrate: If you’re treating diarrhoea or have frequent stools, replace fluids and electrolytes as advised.
• Track symptoms: Note changes in stool frequency, abdominal discomfort, sleep or confusion (if relevant to hepatic encephalopathy). This helps your clinician assess response.
• Avoid skipping or stopping early: Finishing the intended course improves the chance of effectiveness.
• Be mindful of gut recovery: Even after antibiotics, your gut may take time to settle. If symptoms worsen or don’t improve, seek advice rather than self-adjusting.
• Don’t use leftover antibiotics: Using medicines not intended for your diagnosis can be unsafe and ineffective.

Alternative options

Depending on your condition, alternative treatments may include other antibiotics, supportive measures, or non-antibiotic therapies. The best option depends on diagnosis, severity, local guidelines, and individual risk factors.

Common categories of alternatives

• Other antibiotics (for specific bacterial causes or different susceptibility patterns)
• Supportive care (especially for diarrhoea), such as oral rehydration solutions and symptom management under professional guidance
• Gut-focused therapies (for example, targeted treatments for IBS symptoms where appropriate)
• Liver disease management approaches (for hepatic encephalopathy, treatment plans may include additional medications and lifestyle measures)

If you’re asking about alternatives due to side effects, cost, availability, or an incomplete response, discuss options with your pharmacist or clinician.

Market and legal context for Australia

In Australia, medication supply and labelling are governed by the Australian regulatory and scheduling framework. Availability of specific brands and strengths may vary depending on Therapeutic Goods Administration (TGA) listings, pharmacy supply arrangements, and prescribing requirements in accordance with Australian law.

For any antibiotic, it’s important to use it appropriately and only for the indication confirmed by a healthcare professional. This helps reduce the risk of treatment failure and antibiotic resistance.

Recent guidance and evidence overview (high-level)

Clinical guidance for antibiotics—including rifaximin—continues to evolve as new research and antimicrobial stewardship recommendations emerge. Australian healthcare teams typically align with:

• Antimicrobial stewardship principles (use the right antibiotic, for the right duration, for the right patient)
• Local resistance patterns and diagnostic criteria for diarrhoea or gut-related conditions
• Condition-specific liver or gastroenterology guidance for hepatic encephalopathy and bowel disorders

Your pharmacist or prescriber can explain the rationale for rifaximin in your case and whether testing or follow-up is recommended.

Delivery and availability (online pharmacy in Australia)

Xifaxan (rifaximin) availability may depend on stock levels at partner pharmacies and supplier timelines. Delivery options typically vary by location and the pharmacy’s shipping policy.

What you can expect

• Stock checks: Some orders are confirmed after a quick availability check.
• Delivery timeframes: These depend on your postcode and courier service.
• Packaging: Medicines are usually supplied in manufacturer or pharmacy-approved packaging.
• Temperature considerations: Rifaximin tablets generally do not require special cold-chain storage, but follow label directions.

If you need the medicine urgently (for example, to prevent worsening symptoms), contact customer support to ask about dispatch times and alternative options if stock is limited.

Storage instructions

Store rifaximin tablets according to the instructions on the packaging. In general:

• Keep in a cool, dry place away from direct sunlight.
• Keep out of reach of children.
• Do not use after the expiry date printed on the pack.

FAQ

1) Is Xifaxan the same as rifaximin?

Yes. Xifaxan is a brand name that contains rifaximin as the active ingredient.

2) How quickly will I feel better?

Some people notice improvement within a few days, depending on the condition being treated. If you don’t feel improvement after the expected timeframe, contact your pharmacist or prescriber for advice.

3) Can I take rifaximin with food?

Often, rifaximin can be taken with or without food. If your product label or healthcare professional gave specific instructions, follow those. Taking with meals may help if you experience nausea.

4) Does rifaximin cause diarrhoea?

It can sometimes cause gastrointestinal side effects, but it is also used to treat certain diarrhoea-related conditions. If you develop severe watery diarrhoea, fever, or blood/mucus in stool, seek urgent medical advice.

5) Will rifaximin interact with alcohol?

A direct alcohol–rifaximin reaction is not typically expected, but alcohol may worsen underlying liver disease or increase dehydration in diarrhoea. It’s generally safest to avoid alcohol during treatment unless your healthcare professional says otherwise.

6) What should I do if I miss a dose?

Take it when you remember unless it’s almost time for the next dose. Do not take a double dose. If you’re unsure, ask your pharmacist.

7) Who should be extra careful with rifaximin?

Extra caution may be needed for people with liver disease, those taking multiple medicines, pregnant or breastfeeding people, and anyone who has previously had allergic reactions to medications. Always discuss your health history with a clinician or pharmacist.

8) Can I take probiotics while using rifaximin?

Some people consider probiotics after antibiotics, but evidence and suitability vary. Ask your pharmacist, especially if you have severe illness, immunocompromise, or ongoing bowel symptoms.

9) Is antibiotic resistance a concern with rifaximin?

Yes, antibiotic resistance is always a consideration. Using rifaximin for the correct diagnosis and completing the planned course as directed supports appropriate use and stewardship.

10) What should I do if symptoms worsen?

If symptoms worsen significantly—such as increased confusion, severe abdominal pain, high fever, or severe diarrhoea—seek prompt medical help.