Rifaximin

Basic rifaximin information

• International nonproprietary name (INN): Rifaximin
• Brand names available in the United Kingdom: Targaxan (550 mg tablets), Xifaxanta (200 mg tablets)
• ATC code: A07AA11
• Forms and dosages: Film-coated tablets 200 mg and 550 mg
• Manufacturers in the United Kingdom: Norgine
• Registration status in the United Kingdom: Licensed by the MHRA; prescription-only medicine
• OTC / Rx classification: Prescription-only medicine (POM)

Everyday use and best practices

When considering rifaximin as a part of your treatment plan, the timing and method of administration play a crucial role in its effectiveness.

Morning vs evening dosing

For optimal results from rifaximin, it is recommended to take doses consistently at the same times each day. This not only aids in maintaining steady levels of the medication in your system but also enhances adherence to the treatment protocol.

Experts typically suggest the following:

• If prescribed twice daily, consider spacing doses evenly, such as morning and evening.
• Keep a medication schedule or set reminders to ensure timely intake.

Taking with or without meals (UK diet habits)

Food intake can influence how well rifaximin is absorbed in the body. In the UK, where meal patterns may include both heavy and lighter fare, it's good to know:

• Rifaximin can be taken with or without food, but taking it with food may help alleviate potential gastrointestinal discomfort.
• Avoiding high-fat meals right before or after taking rifaximin can be beneficial, as they may reduce absorption.

Safety priorities

Safety should always be paramount when it comes to any medication, and rifaximin is no exception. Understanding who should avoid it and any related precautions is essential.

Who should avoid it (MHRA warnings)

According to the Medicines and Healthcare products Regulatory Agency (MHRA) guidelines, certain groups should steer clear of rifaximin:

• Individuals with severe liver conditions, as this can lead to accumulation and potential toxicity.
• Pregnant women may also be advised against using rifaximin unless absolutely necessary.
• Patients with a known hypersensitivity to rifaximin or any of its excipients.

Activities to limit (driving, work safety)

While rifaximin generally does not impair the ability to drive, some patients may experience side effects such as dizziness or fatigue. It is vital to:

• Evaluate your response to the medication before engaging in activities requiring full alertness, such as driving or operating machinery.
• Discuss any concerns with your healthcare provider to determine if adjustments are needed.

Dosage and adjustments

The correct dosage of rifaximin can vary based on individual circumstances, and understanding the standard regimen can guide effective treatment.

General regimen (NHS guidance)

Typically, rifaximin is prescribed as follows:

• The dose depends on the indication: for hepatic encephalopathy, 550 mg twice daily (as add-on to lactulose); for travellers’ diarrhoea, 200 mg three times daily for 3 days. For IBS with diarrhoea (an off-label use in the UK), 550 mg three times daily for 14 days is used.
• After assessment, doses may be adjusted based on individual response and tolerability.

Special cases (elderly, comorbidities)

The dosing considerations may differ for elderly patients or those with comorbidities. The NHS advises the following:

• Older adults should be monitored closely for adverse effects.
• For patients with kidney issues, careful monitoring of renal function is crucial, often requiring dosage adjustments.

By following these guidelines, healthcare professionals can tailor treatments to maximise effectiveness while ensuring safety.

What’s inside and how it works

Ingredients overview

Rifaximin is composed primarily of the active ingredient rifaximin, a semi-synthetic antibiotic derived from rifampicin. Its formulations might include excipients such as magnesium stearate and microcrystalline cellulose, which serve as binders and stabilisers in the tablets. These components are essential for ensuring the overall effectiveness of the medication, allowing for proper absorption in the gut. It is available as 200 mg and 550 mg tablets.

Mechanism basics explained simply

Understanding how rifaximin works can simplify choices around gut health. This antibiotic primarily targets bacteria within the intestines, inhibiting their RNA synthesis by binding to the bacterial RNA polymerase. Notably, its action is focused on pathogenic strains, leaving the healthy gut flora largely unaffected. Because very little rifaximin is absorbed, its action stays mostly within the gut, which is why it is used for conditions such as hepatic encephalopathy and travellers’ diarrhoea.

Main indications

Approved uses (MHRA listing)

In the UK, rifaximin is licensed by the Medicines and Healthcare products Regulatory Agency (MHRA) for reducing the recurrence of episodes of overt hepatic encephalopathy (550 mg tablets) and for the treatment of travellers’ diarrhoea caused by non-invasive strains of Escherichia coli (200 mg tablets).

Off-label uses in UK clinics

Beyond its licensed indications, rifaximin is sometimes prescribed off-label by specialists, for example for irritable bowel syndrome with diarrhoea and for small intestinal bacterial overgrowth (SIBO). The rationale is its action against bacteria in the gut with little absorption into the body.

Interaction warnings

Food interactions (alcohol, tea/coffee)

When taking rifaximin, it's crucial to consider food interactions. Alcohol consumption can lead to increased side effects and should ideally be avoided during treatment. Additionally, while moderate consumption of coffee or tea may not pose a significant risk, excessive caffeine intake can lead to gastrointestinal upset in some individuals. Patients are encouraged to adopt a moderate diet to mitigate potential interactions while on rifaximin.

Drug conflicts

Rifaximin can interact with ciclosporin and other medicines that inhibit P-glycoprotein, and it may affect the INR in people taking warfarin. Tell your doctor or pharmacist about all medicines you take, and report suspected side effects via the Yellow Card scheme.

Alternative choices

Those seeking alternatives to rifaximin can explore various options, including:

• Lactulose is the standard first-line treatment for hepatic encephalopathy, with rifaximin added if episodes recur.
• Other antibiotics such as metronidazole, which may be effective for certain bacterial infections but carry a higher risk of disrupting healthy gut flora.
• Probiotics can support gut health and restore normal flora but may not provide immediate relief from gastrointestinal symptoms.

Each alternative comes with its pros and cons. For instance, while other antibiotics might show effectiveness, they could also introduce more side effects. Probiotics, meanwhile, are generally well-tolerated but may not resolve acute bacterial infections. Understanding these alternatives is essential for informed decision-making regarding gut health.

Regulation snapshot

In the UK, rifaximin is regulated by the MHRA (Medicines and Healthcare products Regulatory Agency). It is licensed for reducing the recurrence of overt hepatic encephalopathy and for travellers’ diarrhoea, and it is a prescription-only medicine (POM).

Because rifaximin is a prescription-only medicine, patients must consult a healthcare provider to obtain it. Prescribing practices must also follow established guidelines, ensuring that patients receive appropriate doses and explanations regarding usage, helping to mitigate any potential side effects, including risks associated with alcohol consumption during treatment.

Frequently asked questions

Here are some common questions about rifaximin:

• Can rifaximin be taken with other medications?
  It is crucial to consult healthcare professionals before combining rifaximin with other drugs, especially antibiotics like metronidazole, as potential interactions may occur.
• Is it safe to drink alcohol while on rifaximin?
  Alcohol consumption is not recommended as it could exacerbate side effects and impacts on liver function.
• How long does rifaximin take to work?
  This depends on the condition being treated; strict adherence to the prescribed duration is vital for treatment efficacy.
• What are the side effects?
  Common side effects include nausea, abdominal pain, and diarrhoea. Should any severe reactions occur, medical advice must be sought immediately.
• How long is the treatment duration?
  This depends on the indication: travellers’ diarrhoea is treated for 3 days, whereas for hepatic encephalopathy rifaximin is usually taken long term. Follow your prescriber’s instructions.

Guidelines for proper use

Using rifaximin effectively requires understanding its administration and sticking to a treatment plan. Here are some essential counselling tips for UK patients:

• Adhering to prescribing guidelines: Follow the precise dosage and schedule as prescribed by your healthcare professional to maximise efficacy and minimise side effects.
• Monitoring side effects: Keep a watchful eye on any side effects. Noting down changes when starting the medication can be beneficial for future discussions with healthcare providers.
• Keeping appointments: Regular follow-ups are essential for evaluating progress and making necessary adjustments to the treatment plan.
• Seeking pharmacist support: Community pharmacists can provide important advice on medication interactions and side effects.
• NHS resources: Patients are encouraged to take advantage of NHS resources for additional support, information, and services that could enhance their treatment journey with rifaximin.