Xifaxan (Rifaximin) — Patient Information (UK)

Xifaxan contains rifaximin, an antibiotic that works mainly inside the gut. This page explains what it is used for, how it works, how it’s taken, and what to consider while using it. It is written for patients in the United Kingdom and focuses on general information to help you understand your medicine.

Basic product information

Availability and wording of indications can vary by product licence and local guidance. Always follow the instructions supplied with your specific pack.

How Xifaxan works (mechanism of action)

Rifaximin is an antibiotic from the rifamycin group. It targets bacterial DNA synthesis by inhibiting DNA-dependent RNA polymerase, which stops bacteria from producing essential proteins.

Because rifaximin is designed to act largely in the gut and is minimally absorbed, it can reduce gut bacterial activity while limiting drug levels in the rest of the body.

Pharmacokinetics (what the body does to it)

Understanding absorption and elimination can help explain why rifaximin is often used when a gut-focused treatment is preferred.

• Absorption: Rifaximin has low systemic absorption. Most of the medicine stays within the gastrointestinal tract.
• Distribution: Because absorption is limited, systemic distribution is minimal.
• Metabolism: Any systemic metabolism is expected to be limited due to low absorption.
• Elimination: The majority of rifaximin is excreted, mainly through the faeces.
• Implications for interactions: Low absorption can mean fewer “whole-body” interactions, but some medicines can still interact through gut effects or transport mechanisms.

Typical use (what it’s for)

In the UK, rifaximin is used for specific conditions where gut bacteria contribute to symptoms or risk. The most well-established licensed uses include:

• Hepatic encephalopathy (a brain function problem related to severe liver disease), including the reduction of episodes of recurrence after treatment of an acute episode.
• Travellers’ diarrhoea caused by susceptible bacteria (in selected circumstances as advised locally).
• Other gut-related indications may be discussed depending on local clinical protocols and licence status. If your condition is not clearly listed on your packaging, ask your pharmacist or clinician for confirmation.

If you’re using Xifaxan for a particular diagnosis, ensure your treatment plan aligns with UK guidance for that condition. Your healthcare professional can explain why rifaximin was chosen for you.

How and when to take Xifaxan

Always follow the dosing schedule provided with your medication. The sections below give general guidance. Different indications can involve different dose regimens.

Timing

• Take your tablets at the same times each day to keep a consistent approach.
• If you are taking more than one dose per day, spread them out evenly across the day.
• Complete the full course unless told otherwise by your clinician.

Food and swallowing

Rifaximin can be taken with or without food for many patients, but instructions may vary depending on the exact product and indication. In practice:

• If your stomach is sensitive, taking it with a meal may help reduce nausea or discomfort.
• Swallow tablets whole with water. Do not crush unless your pharmacist advises it is safe.

Food interactions (diet considerations)

Because rifaximin is minimally absorbed, most food interactions are less dramatic than with many other antibiotics. However, it’s still sensible to maintain consistent eating habits during your course.

• General approach: Follow the dosing instructions on your label. If “take with food” is written, follow it.
• High-fibre or heavy meals: If you notice your bowel habits change, keep meals similar day-to-day. This can help you gauge how well you are tolerating the medicine.
• Grapefruit and similar foods: No specific grapefruit restriction is commonly required for rifaximin. If you’re using multiple medicines, ask about possible interactions for your full list.

If you have liver disease (including hepatic encephalopathy), your healthcare team may also advise a specific diet or protein plan. Xifaxan does not replace these measures.

Alcohol and medicine interactions

Rifaximin is not usually associated with the same direct interaction patterns seen with some antibiotics (for example, disulfiram-like reactions). However, it is still important to consider alcohol, especially if you are taking it for liver-related problems.

Alcohol

• Hepatic encephalopathy or liver disease: Alcohol can worsen liver function and may aggravate symptoms. It’s generally safest to avoid alcohol or follow your clinician’s advice.
• Other indications: Alcohol may worsen diarrhoea or dehydration risk, which can make symptoms harder to manage.

Interactions with other medicines

Rifaximin’s low systemic absorption reduces the likelihood of major blood-level interactions, but interactions can still occur. Tell your pharmacist or clinician about all medicines you take, including:

• Prescription medicines
• Over-the-counter products (including herbal remedies)
• Supplements and vitamins

In particular, if you take medicines that can affect gut bacteria or bowel transit, or medicines used in liver disease, your clinician may want to review your full regimen.

Indications in more detail

1) Hepatic encephalopathy (liver-related brain dysfunction)

Hepatic encephalopathy can occur when the liver cannot effectively clear toxins from the blood. Rifaximin is used to help reduce the risk of recurrent episodes by acting on gut bacteria that may contribute to toxin production.

2) Travellers’ diarrhoea

Travellers’ diarrhoea is often caused by infectious organisms. Rifaximin may be used when symptoms and local guidance suggest a susceptible bacterial cause.

If you have fever, blood in stools, severe dehydration, or symptoms that are rapidly worsening, seek urgent medical advice. Antibiotics may not be appropriate for every cause of diarrhoea.

Dosing guidance (general)

Dosing depends on the condition being treated. Your prescription label (or the package instructions) will specify the dose and course length for your situation. The information below is general and should not replace your specific instructions.

Common dosing patterns (may vary by licence/indication)

• Hepatic encephalopathy: Often involves a fixed daily regimen taken over a defined duration, commonly used for recurrence prevention after an acute episode. Your clinician will specify the schedule.
• Travellers’ diarrhoea: Often involves a short course taken for a limited number of days.

Do not adjust your dose without advice. If you miss a dose, follow the guidance on the label or ask your pharmacist. In general:

• If you remember soon after, take it as soon as practical.
• If it’s close to the next dose, skip the missed dose and return to your schedule.
• Do not take a double dose to make up for a missed tablet.

Safety profile: what to expect and when to seek help

Like all medicines, rifaximin can cause side effects. Many people experience none or only mild effects. The sections below list possible reactions and safety considerations.

Common side effects

• Headache
• Nausea or stomach discomfort
• Abdominal pain
• Constipation or diarrhoea (may overlap with your underlying illness)
• Fatigue

Less common but important side effects

• Allergic reactions such as rash, itching, swelling of the face/lips, or trouble breathing.
• Severe or persistent diarrhoea (especially with fever or blood/mucus), which may require prompt medical review.
• Liver-related concerns in people with underlying liver disease—seek advice if you notice worsening symptoms.

Seek urgent medical advice if

• You have signs of a serious allergic reaction (swelling, breathing difficulty).
• You develop severe diarrhoea, dehydration, or blood in stool.
• Your symptoms significantly worsen or you feel very unwell.
• For hepatic encephalopathy, you notice confusion, marked drowsiness, or altered behaviour—treat as urgent.

Who should take extra care?

• People with liver impairment or a history of encephalopathy.
• People with a history of allergy to rifamycin antibiotics or any ingredient in the tablet.
• People taking multiple medicines for chronic conditions—ask your pharmacist to review the full list.
• Children and older adults: dosing and suitability should be confirmed by a clinician or pharmacist.

Practical use tips (to get the best results)

• Start on time: Begin your course when advised and keep to the schedule.
• Hydrate during diarrhoea: If you’re taking Xifaxan for diarrhoea, focus on fluids and oral rehydration solutions if needed.
• Don’t stop early: Completing the course helps ensure bacteria are adequately targeted.
• Keep a symptom note: Track stool frequency, urgency, fever, and general wellbeing—helpful for follow-up.
• Avoid sharing antibiotics: Don’t use leftover tablets for a different illness or share with others.
• Probiotics: Some patients use probiotics during/after antibiotics. Evidence varies; discuss with your pharmacist, especially if you’re immunocompromised or have severe illness.

Missed dose, missed days, and what to do

Missing occasional doses may reduce effectiveness. If you miss one:

• Follow the “missed dose” instruction on your label if provided.
• Otherwise, use the general guidance described earlier (don’t double up).
• If you missed multiple doses, contact your pharmacist for advice rather than restarting on your own.

Alternative options

Alternatives depend on the condition being treated, your medical history, allergies, local resistance patterns, and guidance from your healthcare team. Possible alternatives (by category) include:

For travel-related infectious diarrhoea

• Oral rehydration and supportive care (important for all causes of diarrhoea).
• Other antibiotics may be considered if appropriate (choice depends on region, suspected bacteria, and severity).
• Antimotility medicines may sometimes be used short-term in selected situations, but they are not suitable for everyone (especially with blood in stools or high fever).

For hepatic encephalopathy

• Lactulose is commonly used to reduce toxin absorption (your clinician may combine or sequence treatments).
• Other strategies may be considered based on liver status, including evaluation for triggers (constipation, infection, GI bleeding).

Your healthcare professional can explain why rifaximin was selected over alternatives, and what to do if symptoms do not improve.

Market and legal context in the UK

In the UK, medicines are regulated and monitored through the Medicines and Healthcare products Regulatory Agency (MHRA). The availability of Xifaxan and its approved indications can be influenced by product licensing, supply, and ongoing safety monitoring.

UK clinical practice is also informed by guidance from bodies such as the National Institute for Health and Care Excellence (NICE) and relevant specialist associations, as well as local NHS protocols.

If you are purchasing or arranging delivery through an online pharmacy, reputable services will generally require relevant health information and provide information on safe use before dispatch.

Recent guidance (what to know)

Antibiotic use is guided by the principles of antimicrobial stewardship: using the right antibiotic, for the right duration, for the right condition, to reduce resistance and side effects.

• For infectious diarrhoea, many guidelines emphasise supportive care first and reserving antibiotics for more severe cases or specific suspected pathogens.
• For hepatic encephalopathy, guidance commonly focuses on identifying and treating triggers (such as constipation or infection), alongside medicines to reduce gut-derived toxins.
• Safety monitoring includes vigilance for antibiotic-associated diarrhoea and signs of allergy.

Your clinician or pharmacist can share the most up-to-date advice relevant to your diagnosis and situation.

Delivery and availability (UK online pharmacy)

Xifaxan availability may vary based on current stock, strength, pack size, and supply routes. In a reputable UK online pharmacy, ordering typically follows these steps:

• Check availability by pack size/strength on the product listing.
• Complete any required health and delivery information.
• Confirm your order details and delivery address.
• Dispatch times depend on pharmacy processing and courier schedules; tracking is often provided.

If the product is temporarily out of stock, some pharmacies may offer alternative pack options (where appropriate) or advise on expected restock dates.

For best results, store tablets in a cool, dry place and keep them in the original packaging until you’re ready to use them. Keep out of the sight and reach of children.

FAQ — Frequently asked questions

1) Is Xifaxan the same as rifaximin?

Yes. Xifaxan is a brand name containing the active ingredient rifaximin.

2) How quickly will I feel better?

This depends on the condition being treated. For infectious diarrhoea, some people notice improvement within a short time, while others may take a couple of days. For hepatic encephalopathy, improvements can vary and may require ongoing management. If you’re not improving as expected, seek advice.

3) Can I take it with food?

Many patients can take rifaximin with or without food, but follow the instructions on your pack or from your pharmacist. If you have a sensitive stomach, taking it with a meal may feel easier.

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

Take it when you remember unless it’s close to the next dose. Do not take a double dose. If you miss several doses, contact a pharmacist for guidance.

5) Can I drink alcohol while taking Xifaxan?

Avoid alcohol if you have liver disease or hepatic encephalopathy unless your clinician has advised otherwise. For other conditions, alcohol may worsen diarrhoea or dehydration, so it’s best to minimise it.

6) Does rifaximin interact with other medicines?

While rifaximin is minimally absorbed and may have fewer “whole-body” interactions, interactions are still possible. Always tell your pharmacist about all medicines and supplements you use.

7) Are there any warning signs I should watch for?

Seek urgent help for signs of allergy (rash, swelling, breathing difficulty) and for severe diarrhoea with fever or blood. If you are being treated for hepatic encephalopathy and you develop increased confusion or marked drowsiness, treat this as urgent.

8) Can I stop taking it once I feel better?

Try not to stop early. Completing the full course (as instructed) helps ensure the treatment is effective. If side effects occur, ask your pharmacist for advice before stopping.

9) What if the diarrhoea gets worse?

If symptoms worsen, include fever, blood/mucus, severe abdominal pain, or you become dehydrated, seek medical advice promptly.

10) What are common storage instructions?

Keep tablets in the original packaging, in a cool and dry place, and out of the reach of children.

Important note

This information is designed to help you understand Xifaxan (rifaximin). It does not replace medical advice. If you have questions about your condition, dosing, or side effects, speak to your pharmacist or clinician for personalised guidance.