Rifaximin

What is Rifaximin?

Rifaximin is a semi-synthetic rifamycin antibiotic. It acts mainly within the intestine; the Tixtar and Xifaxanta labels describe absorption below 1%. This does not rule out systemic adverse effects or interactions.

The products must be distinguished:

• Spain, Tixtar 550 mg: reduction of recurrent episodes of overt hepatic encephalopathy in adults.
• United Kingdom, Xifaxanta 200 mg: selected traveller’s diarrhoea in adults.
• United States, Xifaxan: includes adult irritable bowel syndrome with diarrhoea (IBS-D). This is not an EMA IBS-D authorisation.
• Spain, Spiraxin 200 mg: has its own authorised indications and schedules. Neither the foreign IBS-D course nor the Xifaxanta schedule should be transferred to it.

How does Rifaximin work?

Rifaximin binds bacterial DNA-dependent RNA polymerase and inhibits RNA synthesis. Its low absorption favours local intestinal action. The precise mechanism in IBS-D is unknown; claims that it reliably corrects dysbiosis, repairs a “leaky gut” or restores a healthier microbiome go beyond the product information.

Who is Rifaximin for?

A clinician must establish the diagnosis and select the actual product. Tixtar is for adults aged 18 years and over, under clinical supervision. The US IBS-D indication is also adult-only; the US age threshold of 12 years applies to traveller’s diarrhoea, not IBS-D. UK Xifaxanta is not recommended below 18 years.

UK Xifaxanta is not for diarrhoea with fever, blood, 8 or more unformed stools in the preceding 24 hours, or occult blood or white blood cells in the stool. It is not effective against invasive enteric pathogens. Seek medical assessment; these findings do not themselves establish a systemic infection or determine an antibiotic.

Do not take Tixtar or Xifaxanta if you have intestinal obstruction or allergy to rifaximin, another rifamycin or any excipient. Pregnancy use is not recommended as a precaution in these labels. During breastfeeding, a clinician must weigh stopping breastfeeding against stopping or avoiding treatment; this is not a blanket labelled contraindication.

Dosage

These are distinct product instructions, not interchangeable Spanish regimens:

These tablets may be taken with or without food. Only the US IBS-D label allows up to two repeat courses for recurrence. UK Xifaxanta must not be used for more than 3 days or given as a second course, even if symptoms persist or soon recur. Do not change or repeat a prescription yourself.

Side effects

Frequencies differ between populations and products; low absorption does not mean no serious adverse effects.

Effects described with UK Xifaxanta

Common effects include headache, dizziness, nausea, abdominal pain, flatulence and rectal tenesmus (a feeling of incomplete emptying). Rash and peripheral oedema are uncommon. These categories must not be transferred to long-term hepatic encephalopathy treatment.

Serious reactions

C. difficile-associated diarrhoea has been reported, including after antibiotic treatment. Persistent or worsening diarrhoea requires assessment; the risk is not merely theoretical.

Anaphylaxis and severe skin reactions, including Stevens–Johnson syndrome and toxic epidermal necrolysis, have been reported with unknown frequency. Stop treatment and seek urgent help for breathing difficulty, swelling, blistering rash or mucosal sores. Rifaximin must never be restarted after a serious reaction such as Stevens–Johnson syndrome or toxic epidermal necrolysis.

Rifaximin and other approaches to digestive symptoms

This comparison is not a treatment ranking or a prescribing pathway. A foreign IBS-D authorisation does not establish a current Spanish treatment option.

How to get Rifaximin online in Europe

Prescrivia is a technology intermediary connecting patients with independent doctors and licensed pharmacies. We do not provide medical services, prescribe, employ doctors, sell or dispense medicines.

1. Assessment: Provide your symptoms or travel plans, medical history and all current medicines.
2. Independent review: A doctor decides whether a prescription is clinically appropriate; Prescrivia does not guarantee a prescription.
3. Dispensing: Any lawful dispensing is the responsibility of a licensed pharmacy, subject to the applicable rules and product availability.

In Spain, distance selling of prescription medicines is prohibited. An online assessment or a product label does not establish that a medicine can legally be supplied or delivered through this platform. This information does not change eligibility or fulfilment rules.

Important safety information

Do not take Tixtar or Xifaxanta with intestinal obstruction or a rifaximin, rifamycin or excipient allergy.

Tell your doctor about:

• Ciclosporin and other P-glycoprotein inhibitors, which can increase exposure.
• Warfarin: INR monitoring is needed when rifaximin is started or stopped; an anticoagulant dose adjustment may be necessary.
• Severe liver disease, kidney impairment and other rifamycins. Tixtar requires particular caution with severe hepatic impairment or MELD scores above 25; other rifamycins are not recommended concurrently.
• Pregnancy or breastfeeding.

The UK Xifaxanta label specifies taking rifaximin at least 2 hours after charcoal.

Stop and seek medical advice if diarrhoea worsens, fever or blood appears, or it fails to improve. The US Xifaxan traveller’s-diarrhoea label specifies stopping if symptoms persist beyond 24–48 hours; UK Xifaxanta must stop after 3 days and must not be repeated. Do not wait for those limits if you are deteriorating. Severe diarrhoea during or after treatment also needs assessment for C. difficile.

Sources

• AEMPS: Tixtar 550 mg, sections 4.1–4.8.
• Norgine: UK Xifaxanta 200 mg, sections 4.1–4.8.
• DailyMed: US Xifaxan, sections 1–2 and 4–8.
• AEMPS: Spiraxin 200 mg.
• BOE: Article 3.5.

This information does not replace advice from a qualified healthcare professional.