Rifamycin Adalvo: Uses, Dosage & Side Effects
A non-systemic, gut-targeted rifamycin antibiotic in a modified-release 200 mg tablet, used in adults to treat travellers’ diarrhoea caused by non-invasive strains of Escherichia coli.
Rifamycin Adalvo is a modified-release oral tablet containing 200 mg of rifamycin, a bactericidal antibiotic of the rifamycin class. Its tablet coating is specifically designed to release the active substance predominantly in the lower small intestine and colon, where gut pathogens responsible for travellers’ diarrhoea live. Because rifamycin from this formulation is only minimally absorbed into the bloodstream, it acts almost entirely on the bacteria inside the gut lumen, shortening the illness without causing the systemic exposure typical of oral antibiotics such as ciprofloxacin or azithromycin. Rifamycin Adalvo is prescription-only and is intended for adults with non-invasive bacterial diarrhoea – typically travellers’ diarrhoea – but is not appropriate for diarrhoea accompanied by high fever, severe abdominal pain or blood in the stool.
Quick Facts: Rifamycin Adalvo
Key Takeaways
- Rifamycin Adalvo is a gut-targeted, non-systemic antibiotic used to treat adult travellers’ diarrhoea caused by non-invasive Escherichia coli strains when the illness is not accompanied by fever or bloody stools.
- The modified-release coating is essential to how the drug works: it bypasses the upper gastrointestinal tract and releases rifamycin in the lower intestine, so tablets must always be swallowed whole.
- The standard treatment is one 200 mg tablet twice daily for three days, giving a total course of six tablets; do not continue beyond three days without medical advice.
- Because absorption into the bloodstream is very low, the commonest side effects are limited to the digestive system – most often headache, mild abdominal discomfort, and constipation; severe reactions are rare.
- Rifamycin Adalvo is not suitable for children under 18, pregnant women without specialist advice, or anyone whose diarrhoea presents with warning signs such as fever, bloody stools, severe dehydration, or persistence beyond 48 hours of starting therapy.
What Is Rifamycin Adalvo and What Is It Used For?
Rifamycin Adalvo contains the active substance rifamycin, a bactericidal antibacterial agent belonging to the rifamycin family, which also includes rifampicin, rifabutin, rifapentine and rifaximin. Unlike rifampicin and rifabutin, however, rifamycin in this formulation is designed to act almost exclusively inside the gastrointestinal tract. The tablet uses a Multi-Matrix (MMX) modified-release technology: a special outer coating resists the acid environment of the stomach and the enzymatic activity of the upper small intestine, so the drug is only released further down the gut – in the distal ileum and colon – where the bacterial pathogens responsible for travellers’ diarrhoea actively replicate.
The principal licensed indication for Rifamycin Adalvo is the treatment of travellers’ diarrhoea caused by non-invasive strains of Escherichia coli in adults. Travellers’ diarrhoea is the most common illness in people visiting countries with different standards of food and water hygiene. It is typically defined as three or more unformed stools within 24 hours, usually accompanied by cramps, urgency, nausea or general malaise, developing during or shortly after international travel. The overwhelming majority of cases are caused by bacteria – enterotoxigenic and enteroaggregative E. coli are the single largest group – acquired from contaminated food or water. Other bacteria (for example Campylobacter, Salmonella, Shigella), viruses (noroviruses, rotavirus) and parasites (Giardia, Cryptosporidium, Entamoeba histolytica) account for a smaller fraction but are much less likely to respond to a gut-active antibiotic.
Rifamycin acts by binding to the beta subunit of the DNA-dependent RNA polymerase enzyme in susceptible bacteria. This binding blocks the transcription step, preventing the bacterium from producing the messenger RNA it needs to synthesise essential proteins. Because the drug inhibits this critical enzyme at very low local concentrations, and because high drug levels are reached directly at the site of infection in the gut, rifamycin is effective against a wide range of enteric pathogens, including many strains of E. coli. Bacteria resistant to rifamycins have arisen occasionally, particularly where rifamycin-class drugs are used systemically, but rates of clinically significant resistance among travellers’ diarrhoea isolates remain low.
A central feature of Rifamycin Adalvo is its extremely low systemic bioavailability. Pharmacokinetic studies demonstrate that plasma concentrations after a single 200 mg dose are generally below 5 ng/mL – far lower than levels associated with pharmacological activity elsewhere in the body. This means the drug is unlikely to interfere meaningfully with most other medications, rarely affects the liver enzymes responsible for drug metabolism, and has a side-effect profile dominated by local, rather than systemic, reactions. In clinical efficacy trials, including a large randomised study in adult travellers with acute diarrhoea, rifamycin MMX significantly reduced the time to last unformed stool compared with placebo and was non-inferior to ciprofloxacin for resolution of diarrhoea, with a comparable safety profile and no new systemic safety signals.
Rifamycin Adalvo is not intended for all causes of diarrhoea. It should not be used when there is blood in the stool (dysentery), persistent high fever (>38.5 °C), or a clinical picture suggestive of invasive bacterial infection, where systemic antibiotics such as azithromycin are preferred. It is also not appropriate for chronic diarrhoea, for inflammatory bowel disease flare-ups, or for Clostridioides difficile-associated diarrhoea – in fact, its use can, in rare cases, trigger C. difficile overgrowth. The medicine is not licensed for prevention of travellers’ diarrhoea; routine prophylaxis with antibiotics is generally discouraged by international travel medicine societies because of concerns about resistance and adverse events.
Conventional oral antibiotics for gastrointestinal infections – such as ciprofloxacin or azithromycin – are rapidly absorbed across the bowel wall into the bloodstream and therefore treat both the gut and the whole body. Rifamycin Adalvo inverts this: its modified-release coating delivers the antibiotic to the lower intestine, where the pathogens live, while limiting systemic absorption. The benefits include fewer systemic side effects, fewer drug interactions, and less disruption to bacteria in more distant parts of the body. The trade-off is that it only works against bacteria that stay inside the gut – which is exactly what makes it appropriate for non-invasive travellers’ diarrhoea.
What Should You Know Before Taking Rifamycin Adalvo?
Contraindications
Certain situations absolutely rule out the use of Rifamycin Adalvo. Before starting treatment, check carefully whether any of the following apply to you.
- Hypersensitivity to rifamycin or rifamycin derivatives: Do not take this medicine if you have ever had an allergic reaction to rifamycin, rifaximin, rifampicin, rifabutin, rifapentine, or to any of the tablet’s excipients. Cross-reactivity within the rifamycin family is well documented.
- Diarrhoea with fever or bloody stools: Rifamycin Adalvo is not indicated for diarrhoea accompanied by fever (>38.5 °C), bloody stools, severe abdominal pain, or signs of systemic illness – all of which may point to an invasive pathogen (for example Shigella, Salmonella enterica serotype Typhi, Campylobacter jejuni) that requires a systemically absorbed antibiotic or other specific therapy.
- Known infection with pathogens not susceptible to rifamycin: The drug is not active against common causes of viral or parasitic diarrhoea and will not help in those settings. Children and pregnant women should be evaluated for non-bacterial causes before any antibiotic is considered.
- Intestinal obstruction or severe structural gut disease: Because the modified-release coating relies on intact gastrointestinal transit, tablets should not be used in patients with known or suspected mechanical obstruction.
Warnings and Precautions
Stop taking Rifamycin Adalvo and contact a doctor without delay if during treatment you develop: persistent fever above 38.5 °C, bloody or black tarry stools, severe or progressive abdominal pain, signs of dehydration (very dark urine, dizziness, lightheadedness, reduced urination, extreme thirst), symptoms of an allergic reaction (swelling of the lips, face, tongue or throat, difficulty breathing, widespread rash), or diarrhoea that continues or worsens after 48 hours of treatment. These features may indicate an invasive infection, a severe adverse reaction, or Clostridioides difficile-associated colitis, and require reassessment.
In addition to the absolute contraindications, inform your doctor if any of the following apply before or during treatment:
- Previous rifamycin exposure: If you have taken rifaximin, rifampicin or other rifamycins within the past few months, tell your doctor. Prior exposure can affect the likelihood of resistance in intestinal bacteria and influence your personal risk of adverse effects.
- Severe hepatic impairment: Although systemic exposure after oral rifamycin is low, data in severe liver disease are limited. The drug should be used with caution in these patients and only if no safer alternative is available.
- Renal impairment: Because rifamycin is eliminated almost entirely in the faeces rather than by the kidneys, dose adjustment for renal function is generally not required. Nonetheless, patients with significant kidney disease should be reviewed individually.
- History of Clostridioides difficile infection: Like almost all antibiotics, rifamycin can alter gut flora and, rarely, allow overgrowth of C. difficile. Patients with previous antibiotic-associated colitis should be counselled to report new-onset watery diarrhoea, abdominal pain or fever during or after a course.
- Pre-existing gastrointestinal disease: Inflammatory bowel disease, irritable bowel syndrome with coexisting infection, or recent bowel surgery may change transit time through the intestine and theoretically alter where and how much rifamycin is released.
- Allergy to polysorbates, colourings, or other excipients: See the list of inactive ingredients in section “What Does Rifamycin Adalvo Contain?”.
- Driving and operating machinery: Rifamycin Adalvo is unlikely to impair the ability to drive or use machines. If dizziness or severe headache occur, do not drive or operate machinery until these have resolved.
Your prescriber will also consider whether your symptoms may have a non-bacterial cause. Oral rehydration remains the cornerstone of management for mild to moderate travellers’ diarrhoea, and many cases resolve within 72 hours without any antibiotic. Antibiotic therapy should be reserved for moderate to severe illness or for travellers whose itinerary would be significantly disrupted by prolonged diarrhoea.
Pregnancy and Breastfeeding
The safety of Rifamycin Adalvo in pregnancy has not been formally established in adequate controlled studies. Because systemic absorption of the drug is very low, fetal exposure is also expected to be low, but human experience remains limited. As a general rule, Rifamycin Adalvo should only be used during pregnancy if the potential benefit to the mother clearly outweighs the potential risk to the fetus, and after discussion with a doctor familiar with travel-related infections. Pregnant travellers with diarrhoea should prioritise aggressive oral rehydration, dietary modification, and, where appropriate, antiemetics or loperamide under medical supervision, before considering antibiotics.
It is not known whether rifamycin or its metabolites pass into human breast milk in clinically significant amounts. Given the drug’s low systemic absorption, transfer into milk is likely to be minimal, but formal lactation studies are lacking. Women who are breastfeeding should inform their doctor before starting treatment, so that the benefits and risks can be weighed individually. If the medicine is prescribed, watch the infant for any unexpected symptoms such as diarrhoea, rash or feeding changes and report these promptly.
Effects on Fertility
There is no evidence that rifamycin affects male or female fertility at the licensed oral dose. Animal studies with related rifamycins have not shown consistent effects on reproductive parameters, and low systemic exposure from Rifamycin Adalvo further reduces any theoretical concern. Nonetheless, couples actively planning pregnancy who have concerns should discuss alternatives with their doctor.
Use in Children and Adolescents
The safety and efficacy of Rifamycin Adalvo in children and adolescents below 18 years of age have not been established. Clinical trials supporting the approval were conducted in adults, and there is insufficient evidence to recommend the dose or formulation for younger patients. Children with travellers’ diarrhoea should be managed primarily with rehydration and assessed by a paediatrician or travel medicine specialist before any antibiotic is considered.
Use in Older Adults
No dose adjustment is required for otherwise healthy older adults, and clinical trials have not shown a clinically important difference in response or adverse event rates compared with younger adults. Nevertheless, older travellers may have a higher baseline risk of dehydration, comorbid conditions, and polypharmacy; review of concurrent medications is therefore particularly important in this group.
How Does Rifamycin Adalvo Interact with Other Drugs?
Interactions with Rifamycin Adalvo are best understood in two parts: interactions that affect the drug’s activity in the gut, and interactions that affect other medications through systemic exposure. Because systemic exposure is very low at therapeutic doses, the potential for rifamycin to modify the metabolism of other drugs is limited. However, as a class, rifamycins are classical CYP3A4 inducers, and prescribing information follows a cautious approach in line with that wider class effect. Always tell your doctor or pharmacist about all medicines, supplements and herbal products you take, including short courses taken during travel.
Major Interactions
| Interacting Drug or Drug Class | Effect | Clinical Significance |
|---|---|---|
| Hormonal contraceptives (combined oral contraceptives, progestogen-only pill, patches, rings, implants containing oestrogens/progestogens) | Theoretical reduction in contraceptive efficacy through CYP3A4 induction (class effect of rifamycins) | Use an additional non-hormonal contraceptive method (e.g. condoms) during treatment and for 7 days after the last dose; follow your prescriber’s advice. |
| Warfarin and other vitamin K antagonists | Rifamycins may reduce the anticoagulant effect; gastrointestinal infection itself can also affect INR | Monitor INR more frequently during and shortly after treatment; dose adjustment may be needed. |
| Other rifamycin-class antibiotics (rifaximin, rifampicin, rifabutin, rifapentine) | No additional benefit and increased risk of overlapping adverse effects, cross-resistance development | Do not combine – use only one rifamycin at a time unless specifically directed by a specialist. |
| BCG and other live bacterial vaccines | Antibacterial activity in the gut may inactivate oral live bacterial vaccines (e.g. oral typhoid vaccine Ty21a) | Separate administration – complete oral vaccine course before starting antibiotic therapy. |
Other Relevant Interactions
| Interacting Drug or Drug Class | Effect | Clinical Significance |
|---|---|---|
| CYP3A4 substrates with narrow therapeutic index (e.g. tacrolimus, ciclosporin, some antiretrovirals) | Theoretical reduction in plasma concentrations via enzyme induction (class effect) | Clinically significant interactions are unlikely at usual rifamycin Adalvo doses; nevertheless, consult a specialist in transplant or HIV care. |
| P-glycoprotein (P-gp) substrates (e.g. digoxin) | Potential for altered intestinal absorption via P-gp interactions | Consider monitoring plasma levels for digoxin in high-risk patients if prolonged treatment is given. |
| Antacids, proton-pump inhibitors, H₂ blockers | Changes in gastric pH could theoretically affect tablet integrity, but modified-release coating is designed to resist pH changes | No specific dose adjustment; take rifamycin Adalvo at its prescribed times. |
| Loperamide and anti-motility agents | May be co-administered for symptomatic relief in travellers’ diarrhoea without infection signs | Do not use loperamide alone if fever or bloody stools are present; discuss with your doctor. |
| Probiotics (e.g. Saccharomyces boulardii, lactobacillus strains) | May be used as adjunctive therapy; no pharmacokinetic interaction expected | Generally safe but separate doses of live probiotics from antibiotic doses by several hours. |
Grapefruit, grapefruit juice, alcohol and commonly used over-the-counter cold or allergy remedies have not been shown to interact in a clinically meaningful way with rifamycin at the approved dose. Nonetheless, excess alcohol is best avoided during an episode of diarrhoea because it may worsen dehydration. If you are unsure whether a medicine you buy over the counter is safe to take alongside Rifamycin Adalvo, ask a pharmacist.
What Is the Correct Dosage of Rifamycin Adalvo?
Rifamycin Adalvo is intended as a short, targeted course of treatment. The standard regimen has been validated in controlled clinical trials in adult travellers with acute diarrhoea. Always follow the exact instructions of your prescribing doctor or pharmacist. The information below is a general summary and does not replace individual medical advice.
Adults
Standard Adult Dose
Indication: Travellers’ diarrhoea caused by non-invasive strains of Escherichia coli in adults
Dose: One 200 mg modified-release tablet orally twice daily, approximately every 12 hours
Duration: Three consecutive days (total of six tablets)
Administration: Swallow whole with water, with or without food. Do not crush, break or chew.
The full three-day course should be completed even if symptoms improve earlier, to ensure that the bacteria responsible for the infection are adequately suppressed. If diarrhoea has not improved within 48 hours of starting treatment, or if warning symptoms appear (see the “Warnings and Precautions” section), you should stop the medicine and seek medical review rather than continuing beyond three days or switching to a different antibiotic on your own.
Children and Adolescents
Rifamycin Adalvo is not authorised for use in patients below 18 years of age. Clinical data in children and adolescents are insufficient to establish either a safe dose or a comparable efficacy profile, and the size and modified-release design of the tablet are not suitable for younger children. If a child or adolescent develops diarrhoea during or after travel, the first priority is oral rehydration therapy, a careful clinical assessment, and – if antibiotics are judged necessary – selection of an age-appropriate alternative such as azithromycin at paediatric doses.
Older Adults (65 Years and Above)
No dose adjustment is required for older adults on the basis of age alone. The regimen of one 200 mg tablet twice daily for three days applies equally. However, older patients are more likely to have multiple comorbidities, polypharmacy and a higher risk of dehydration during a diarrhoeal illness, so a more thorough initial assessment is sensible. Particular attention should be paid to fluid balance, cardiovascular stability, and concurrent use of anticoagulants or other narrow-therapeutic-index drugs.
Patients with Kidney or Liver Problems
Because rifamycin in this formulation undergoes essentially negligible renal elimination, no dose adjustment is required in patients with mild, moderate or severe renal impairment. For hepatic impairment, systemic exposure is already very low, so dose adjustment is not routinely needed, but patients with severe liver disease should be reviewed individually. There are no specific contraindications to using Rifamycin Adalvo in patients on haemodialysis, but clinical experience in this setting is limited.
Missed Dose
If you forget a dose, take it as soon as you remember on the same day, and continue with your regular schedule. If it is almost time for the next dose, skip the missed tablet and take only the scheduled one – do not double up to make up for a missed tablet. Because the course is only six tablets in total, missing more than one or two doses may reduce the efficacy of treatment; contact your doctor or pharmacist for advice if this happens.
Overdose
There is no specific antidote for rifamycin overdose. Because absorption from the modified-release tablet is very low, even large oral overdoses are expected to produce limited systemic toxicity. Reported symptoms of overdose have been mild and predominantly gastrointestinal, including nausea, abdominal discomfort, and headache. If more than the prescribed dose has been taken, contact a doctor, poison information centre or emergency department; bring the medicine packaging with you. Management is symptomatic and supportive, with attention to hydration and electrolyte balance.
The modified-release coating is what allows Rifamycin Adalvo to deliver its active ingredient to the lower intestine, where the infection occurs. Splitting, crushing or chewing the tablet destroys this coating and allows rifamycin to be released and partly absorbed too early – reducing its effect at the intended site and increasing the chance of upper-gut side effects. Always swallow each tablet whole.
What Are the Side Effects of Rifamycin Adalvo?
Like all medicines, Rifamycin Adalvo can cause side effects, although not everyone experiences them. The frequency estimates below follow the conventional Medical Dictionary for Regulatory Activities (MedDRA) categories used in European prescribing information and are based on data from controlled clinical trials and post-marketing surveillance of rifamycin in the MMX modified-release formulation. Individual clinical labels may vary slightly; always consult the package leaflet supplied with your specific medicine.
Side Effects by Frequency
Very Common
May affect more than 1 in 10 people
- Headache
Common
May affect up to 1 in 10 people
- Constipation
- Abdominal pain or discomfort
- Abdominal distension (bloating)
- Urgency of defecation (sudden, compelling need to pass a stool)
- Nausea
- Dyspepsia (indigestion, upper-abdominal discomfort)
- Flatulence
- Dizziness
Uncommon
May affect up to 1 in 100 people
- Altered stool colour (for example pink or reddish discoloration)
- Vomiting
- Dry mouth
- Rash or pruritus (itching)
- Muscle or joint pain
- Tiredness (fatigue)
- Raised liver enzymes on blood testing
Rare
May affect up to 1 in 1,000 people
- Urticaria (hives)
- Hypersensitivity reactions including facial or lip swelling
- Reddish or orange discoloration of urine, tears or saliva (class effect of rifamycins)
- Clostridioides difficile-associated diarrhoea or colitis, which may range from mild to severe
Not Known
Frequency cannot be estimated from available data
- Anaphylactic reactions (severe, potentially life-threatening allergic reactions)
- Severe cutaneous adverse reactions such as Stevens-Johnson syndrome (reported rarely with rifamycin-class drugs)
- Interstitial nephritis and hepatitis (rare with systemic rifamycins; very rare given low absorption of this formulation)
Recognising and Managing Common Side Effects
Headache is the most frequently reported side effect. It is usually mild, self-limiting, and responds to paracetamol or, where appropriate, ibuprofen. Dehydration from the underlying diarrhoea can contribute to headache, so maintaining adequate oral rehydration is an important first step. If headache is severe, persistent, or associated with neurological symptoms, seek medical attention.
Gastrointestinal symptoms such as constipation, cramps, bloating and nausea may be difficult to separate from symptoms of the underlying diarrhoea. Because Rifamycin Adalvo alters the colonic microbiota and shortens diarrhoea, transient constipation after several days of loose stools is not unusual. Increasing fluid and fibre intake, and gentle mobilisation, usually resolve the issue. Severe, unremitting abdominal pain is not typical and should prompt medical review.
Allergic reactions are rare but can be serious. Stop taking the medicine immediately and seek urgent medical attention if you develop a widespread rash, facial or lip swelling, wheeze, difficulty breathing, or faintness after a dose. Be aware that cross-reactivity between rifamycin derivatives is possible, so prior reactions to rifaximin, rifampicin, rifabutin or rifapentine should be disclosed before starting Rifamycin Adalvo.
Clostridioides difficile-associated diarrhoea is a recognised but rare complication of almost any antibiotic course, including rifamycin. It should be considered if watery diarrhoea, abdominal pain or fever develop during or within several weeks after completing treatment, particularly in patients with healthcare exposure or prior antibiotic use. Specific testing and targeted therapy are required, and Rifamycin Adalvo should be discontinued.
Reporting of suspected adverse reactions after authorisation is an important way to continue monitoring the benefit-risk balance of a medicine. You can report side effects directly via your national pharmacovigilance system, for example the MHRA Yellow Card Scheme in the United Kingdom, the FDA MedWatch program in the United States, or the EMA EudraVigilance network in the European Union.
How Should Rifamycin Adalvo Be Stored?
Proper storage is important for maintaining the integrity of the modified-release coating that gives Rifamycin Adalvo its characteristic gut-targeted action. Exposure to high temperatures, humidity or direct sunlight can compromise this coating and reduce the efficacy of the medicine. Follow these storage instructions carefully:
- Temperature: Store below 30 °C. Avoid keeping the medicine in hot places such as a car on a sunny day, a window sill, or a bathroom cabinet subject to high humidity. Do not refrigerate or freeze.
- Humidity and light: Keep tablets in the original blister and outer carton to protect from moisture and light. Do not remove a tablet from the blister until you are ready to take it.
- Expiry date: Do not use the medicine after the expiry date (EXP) printed on the blister and carton. The expiry date refers to the last day of the stated month.
- Child safety: Keep the medicine out of the sight and reach of children. Accidental ingestion should be reported to a poison information service even if the child appears well.
- Disposal: Do not throw away any medicines via wastewater or household waste. Ask your pharmacist how to dispose of medicines no longer required. These measures help protect the environment.
- Travel storage: When travelling, keep the tablets in your carry-on bag rather than in checked luggage, which may be exposed to extreme temperatures. Avoid direct sun exposure in hot climates.
If you notice any change in the appearance of the tablets – for example cracking of the coating, discoloration, stickiness, or a strong unusual smell – do not use them and return the pack to a pharmacy.
What Does Rifamycin Adalvo Contain?
Active Substance
The active substance is rifamycin, present as rifamycin sodium. Each film-coated, modified-release tablet contains the equivalent of 200 mg of rifamycin. Rifamycin is a semi-synthetic antibacterial of the rifamycin class and exerts its effect by inhibiting bacterial DNA-dependent RNA polymerase, thereby suppressing protein synthesis in susceptible organisms.
Excipients (Inactive Ingredients)
The exact list of excipients is defined by the national Summary of Product Characteristics for the product you receive, but typical inactive ingredients in rifamycin modified-release tablets include:
- Cellulose-derived polymers forming the modified-release matrix (e.g. hypromellose, ethylcellulose)
- Lipophilic excipients and waxes that contribute to controlled dissolution
- Silicon dioxide (anti-caking agent)
- Magnesium stearate (tablet lubricant)
- Film-coating polymers and colours (e.g. titanium dioxide, iron oxide pigments)
- Stearic acid
If you know you are allergic to any excipient listed on the package leaflet – particularly colouring agents, lactose monohydrate (where present) or polysorbates – tell your doctor or pharmacist before starting treatment. The exact composition of excipients is listed on the package leaflet supplied with every pack.
Appearance and Pack Size
Rifamycin Adalvo modified-release tablets are typically presented as film-coated, oval tablets with a distinctive pink or pinkish-red colour that reflects the intrinsic red-orange hue of the rifamycin molecule. Pack sizes reflect the standard three-day course: blister packs containing six tablets (enough for one complete treatment course) are the most common presentation, although larger packs may be available in some markets.
Marketing Authorisation Holder and Manufacturer
The marketing authorisation holder is Adalvo Ltd. Manufacturing and quality-control details, together with local contact information for reporting suspected adverse reactions, are printed on the outer carton and in the package leaflet supplied with your specific medicine. Always keep the carton for reference throughout and after treatment.
Frequently Asked Questions About Rifamycin Adalvo
Rifamycin Adalvo is prescribed to adults to treat travellers’ diarrhoea caused by non-invasive strains of Escherichia coli. It is a non-systemic antibiotic, meaning it acts almost entirely inside the gut. It is not suitable for dysentery-type diarrhoea, diarrhoea with high fever, persistent bloody stools, or infections caused by invasive pathogens such as Shigella, Salmonella Typhi or Campylobacter, which require systemically absorbed antibiotics such as azithromycin or ciprofloxacin.
Take one 200 mg modified-release tablet twice daily – approximately every 12 hours – for three consecutive days, giving a total of six tablets. Swallow each tablet whole with a glass of water, with or without food. Never crush, break or chew the tablets, as the coating is what enables the drug to reach the lower intestine where it is most effective. If you miss a dose, take it as soon as you remember on the same day, unless it is almost time for the next scheduled dose.
Most people experience a noticeable reduction in stool frequency within 24–48 hours of starting treatment. In pivotal clinical trials, rifamycin MMX significantly shortened the time to last unformed stool compared with placebo and was non-inferior to ciprofloxacin. If your diarrhoea has not improved after 48 hours, or if you develop fever, bloody stools, severe abdominal pain, or signs of dehydration, stop the tablets and seek medical advice, as a different treatment may be needed.
Rifamycin is only minimally absorbed from the gut, so clinically significant systemic interactions are unlikely at the approved dose. However, the rifamycin class as a whole is known to induce CYP3A4, the liver enzyme that breaks down many hormonal contraceptives. As a precaution, most prescribing information advises women using combined oral contraceptives, progestogen-only pills, patches, rings, implants or injections to use an additional non-hormonal contraceptive method (such as condoms) during treatment and for seven days after the last dose. Confirm individual advice with your prescriber.
There are limited human data on rifamycin use in pregnancy. Because absorption into the bloodstream is very low, fetal exposure is expected to be small, but the medicine should only be used during pregnancy if clearly necessary and prescribed by a doctor. Rehydration and dietary measures are the first priority for pregnant women with travellers’ diarrhoea. It is not known whether rifamycin passes into breast milk in clinically relevant amounts; women who are breastfeeding should discuss the benefits and risks with their doctor before starting treatment.
There is no specific pharmacological interaction between rifamycin and alcohol at the approved oral dose, and no disulfiram-like reaction has been described. However, alcohol is a diuretic and can worsen dehydration during a diarrhoeal illness, so moderation is sensible. Alcohol may also irritate an already inflamed bowel and can cause nausea and vomiting, making it harder to recover. Wait until symptoms have settled before resuming significant alcohol intake, and check individual advice with your doctor or pharmacist if you have underlying liver disease.
Rifamycins intrinsically have a red-orange colour, and systemic rifamycins such as rifampicin are well known to turn urine, sweat, tears and soft contact lenses orange. Because Rifamycin Adalvo is only minimally absorbed, these discolorations are uncommon and usually mild. However, faint pink, orange, or red discoloration of stools can occur during treatment and is harmless. If you wear soft contact lenses and notice persistent discoloration, discuss with your optometrist; hard lenses are generally not affected.
References
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- U.S. Food and Drug Administration (FDA). Aemcolo (rifamycin) Prescribing Information. Revised 2024. Available from: FDA Drug Label.
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- World Health Organization (WHO). International travel and health: diarrhoeal diseases. Geneva: WHO; 2024.
- Joint Formulary Committee. British National Formulary (BNF). London: BMJ Group and Pharmaceutical Press; updated 2025.
- Centers for Disease Control and Prevention (CDC). Travelers’ Health Yellow Book: Travelers’ Diarrhea. Atlanta: CDC; 2024.
- Hu Y, Ren J, Zhan M, et al. Efficacy of rifaximin and related rifamycins in the prevention and treatment of travelers’ diarrhoea: a systematic review and meta-analysis. PLoS One. 2022;17(4):e0267003. doi:10.1371/journal.pone.0267003.
Editorial Team
This article was written and reviewed by the iMedic Medical Editorial Team, comprising licensed specialist physicians with expertise in infectious diseases, travel medicine, gastroenterology and clinical pharmacology.
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