Tixtar

Quick links to important sections

Medically reviewed

Laura Arias

Last updated on 22/12/2025

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Tixtar

Property Description
Active ingredient Rifaximin
Form Oral Tablet
Pharmacological Class Rifamycin Antibacterial / Non-systemic Antibiotic
General Purpose Modulates gut bacteria population
Origin Semisynthetic

What is Tixtar and its Active Ingredient?

Tixtar is a branded, prescription-only medication that functions as an Anti-infective agent specifically targeting the gastrointestinal tract. The sole active ingredient is Rifaximin, which is chemically defined as a Rifamycin derivative and classified as a Rifamycin Antibacterial.

Rifaximin is a semisynthetic compound that falls under the general class of Antibiotics. The structure ensures that it acts as an RNA polymerase inhibitor, selectively blocking the growth and multiplication of susceptible gut bacteria. This action is clinically recognized for managing bacterial composition in the gut, as Rifaximin is unique because it is "virtually unabsorbed from the gastrointestinal tract, leading to high intraluminal concentrations."

Tixtar’s Unique Class: A Non-Systemic Oral Antibiotic

Tixtar is distinctively classified as a non-systemic antibiotic delivered via an oral tablet. This means the formulation is intentionally designed for minimal systemic absorption, ensuring that the drug remains highly concentrated in the intestine rather than distributing significantly throughout the body.

Rifaximin’s limited absorption serves as the basis for its function as a Gastrointestinal-specific antibiotic, providing a local action in the gut. This underscores that its therapeutic approach is strictly focused on modifying the bacterial environment within the gut, a key feature distinguishing it from systemically absorbed antibacterial agents.

What is the General Purpose of Rifaximin?

the general purpose of Rifaximin is to reduce and modulate the population of specific susceptible bacteria within the intestines. This action is critical for helping to restore a more functional balance in the internal microbial environment.

As a Gastrointestinal-specific antibiotic, its mechanism involves acting as an RNA polymerase inhibitor, selectively disrupting the growth processes of targeted bacteria in the gut. This therapeutic approach is concentrated on modifying the environment where the bacteria are overgrown or imbalanced, without being intended for the treatment of systemic bacterial infections.

What side effects are possible with Tixtar?

Possible side effects and safety information

Tixtar (Rifaximin) is a non-systemic antibiotic with a safety profile primarily reflecting its minimal absorption from the gastrointestinal tract, as documented in official regulatory labeling. Adverse reactions are classified by frequency, based on clinical trial data for approved indications.

Frequency-Classified Adverse Reactions

Adverse effects listed as Common (occurring in up to 1 in 10 individuals) in regulatory documents predominantly involve the Gastrointestinal System and Nervous System.

System-Organ Class Common Adverse Reactions
Gastrointestinal Disorders Abdominal pain, Nausea, Vomiting, Flatulence, Ascites, Defecation urgency
Nervous System Disorders Headache, Dizziness
General Disorders Peripheral edema, Fatigue, Pyrexia (Fever)

Serious Adverse Reactions and Safety Constraints

Official labeling mandates the documentation of rare but clinically significant adverse reactions. These include Clostridium difficile-Associated Diarrhea (CDAD), which can occur during or up to two months after treatment cessation, and severe Hypersensitivity Reactions such as anaphylaxis and Severe Cutaneous Adverse Reactions (SCARs), including Stevens-Johnson syndrome (SJS) and Toxic Epidermal Necrolysis (TEN).

Safety constraints are defined by known drug properties and regulatory data. Tixtar is contraindicated in individuals with a known hypersensitivity to Rifaximin or any rifamycin agent. Specific caution is advised for patients with severe hepatic impairment (Child-Pugh Class C) due to noted increases in the minimal systemic exposure. Furthermore, the product label notes that co-administration with strong P-glycoprotein (P-gp) inhibitors can substantially increase the systemic concentration of Rifaximin.

Overdose and Emergency Response

Overdose and when to seek help

The official regulatory profile for Tixtar (Rifaximin) notes that due to its minimal systemic absorption, no unique or characteristic symptoms of acute overdose have been formally documented. In clinical studies referenced in regulatory documents, single doses up to 2400 mg or repeated doses up to 1800 mg per day for seven days were administered without reports of specific named toxicity in the Overdosage section.

Management of an overdose is based entirely on symptomatic and supportive treatment, as regulatory documents explicitly state that no specific antidote is known for Rifaximin. Consequently, drug removal procedures such as hemodialysis are not expected to be effective.

Urgent medical attention is required for any suspected overdose. Regulator-aligned guidance states that emergency services must be contacted immediately if the individual who has taken the medication collapses, has a seizure, or experiences trouble breathing or if they cannot be awakened. Contacting a poison control center is also a required action following any suspected high-dose exposure. A population-specific consideration noted in the label is that systemic exposure is significantly increased in patients with severe hepatic impairment (Child-Pugh Class C), a factor relevant during any high exposure event.

Therapeutic Uses of Tixtar

What Tixtar Treats: Main Uses and Benefits

Tixtar (rifaximin) is commonly used to help with specific conditions involving inflammatory or irritative processes that affect the gastrointestinal tract, as well as managing a complication of advanced liver disease. It is applied in addressing scenarios where short-term symptomatic assistance or maintenance support is needed for chronic conditions. The medicine is considered relevant in contexts involving heightened systemic burden.

In clinical use, Tixtar is used to address the recurrence of overt hepatic encephalopathy (HE), management of Irritable Bowel Syndrome with Diarrhea (IBS-D), and treatment of travelers' diarrhea (TD) caused by noninvasive E. coli.

The medicine generally contributes to easing the overall symptom burden during these episodic or fluctuating manifestations. It provides support that helps ease symptoms like confusion and cognitive changes in HE, and assists with maintaining functional stability and managing abdominal discomfort and diarrhea in IBS-D and TD. Patients often find that the medicine supports general well-being during symptomatic phases.


Quick Fact: Support for Symptom Management The medicine is considered relevant in clinical settings that involve acute or unstable symptom patterns related to the gut, such as those that can interfere with daily functioning.

Eligibility and Restrictions for Use

Who Can and Cannot Use Tixtar? (Rifaximin)

Eligibility for Tixtar is strictly defined by regulatory authorities based on patient characteristics, pre-existing conditions, and age.


Populations and Conditions

Category Regulatory Eligibility Status
Approved Age Groups Adults (≥18 years) for Hepatic Encephalopathy (HE) and Irritable Bowel Syndrome with Diarrhea (IBS-D). Adolescents (≥12 years) for Travelers' Diarrhea (TD).
Absolute Contraindications Patients with known hypersensitivity to Rifaximin or any other rifamycin antimicrobial agent.
Condition-Based Exclusion Not recommended for diarrhea complicated by fever or blood in the stool, or in cases of intestinal obstruction.
Pediatric Limitations Use for HE and IBS-D is not established in patients under 18 years; contraindicated for TD in children under 12 years of age.
Hepatic Impairment Use requires caution in patients with severe hepatic impairment (Child-Pugh C) due to increased systemic exposure.
Pregnancy and Lactation Not recommended during pregnancy. For lactation, a decision must be made to discontinue either breastfeeding or the medicine.

Eligibility Summary

Regulatory documents establish absolute non-eligibility based on allergy to the rifamycin drug class. Eligibility is limited by minimum age thresholds specific to each indication and by cautions required for severe liver impairment. The drug is not recommended when the diarrhea indicates an invasive infection or when severe gastrointestinal blockage is present.

What should I know about interactions with other medicines?

Tixtar Interactions with other medicines and products

Tixtar (rifaximin) is designed to act locally within the gut, but specific drug combinations and physiological conditions can significantly alter its pharmacokinetic profile.

Documented Pharmacokinetic Interactions

Co-administration with P-glycoprotein (P-gp) inhibitors is a primary interaction concern. Rifaximin is a substrate of the P-gp efflux transporter, and regulatory documents state that combining it with a P-gp inhibitor, such as Cyclosporine, substantially increases the systemic exposure of rifaximin. For example, co-administration with Cyclosporine has been officially documented to result in up to a 124-fold increase in rifaximin AUC.

Furthermore, systemic exposure is already significantly increased in patients with severe hepatic impairment (Child-Pugh Class C). The official documentation notes a potential additive effect where reduced clearance from hepatic impairment and concomitant P-gp inhibitors may further increase systemic exposure.

Other Official Interaction Statements

Interacting Substance/Class Official Interaction Outcome
Warfarin (Oral Anticoagulants) Changes in International Normalized Ratio (INR) have been reported.
Live Bacterial Vaccines Therapeutic efficacy can be decreased due to antibacterial action.
High-fat Meal Increased systemic exposure (AUC) by 2-fold, though the clinical relevance is minor.
Midazolam / Oral Contraceptives Clinical studies demonstrated no significant effect on the pharmacokinetics of these tested CYP3A4 substrates.

Mechanism of Action

How Tixtar Works: Dual Mechanism of Action


Inhibition of Bacterial Transcription and Proliferation

The primary mechanism of Rifaximin involves highly localized action within the intestinal tract. It binds specifically to the beta-subunit of DNA-dependent RNA polymerase in susceptible bacteria. This interaction acts as an inhibitor of bacterial RNA synthesis, halting the transcription process and the subsequent replication of microbial cells. The resulting physiological consequence is the rapid, localized reduction in the population density of targeted bacteria within the gut lumen, which results in the modulation of the microbial population.

Host PXR Agonism and Barrier Stabilization

A secondary, non-antibiotic mechanistic domain involves the drug acting as an agonist on the human Pregnane X Receptor (PXR) present in the intestinal epithelial cells. PXR activation is known to modulate the NF-κB signaling pathway, which centrally controls localized inflammatory signaling. This action contributes to the suppression of NF-κB signaling and results in the stabilization of the intestinal epithelial barrier function, a consequence of stabilizing epithelial barrier function.

Mechanistic Localization and Constraint

The entire mechanism is defined by the drug's near-zero systemic absorption, ensuring that the full pharmacological effect remains localized to the gut lumen and its lining. This peripheral focus is the key mechanistic constraint, meaning the mechanism is constrained to the GI lumen, rendering it inactive against systemic targets, but resulting in high drug concentrations at the mucosal surface.

Dosage and Administration Information

How Tixtar is Used: Standard Administration Guidelines

Tixtar (rifaximin) is used according to specific administration protocols, with dosages and duration determined by the condition being addressed. The medication is an oral tablet that is intentionally designed to be minimally absorbed from the gastrointestinal tract, concentrating its action within the intestines.


Standard Administration and Dosing

The route of administration is oral for all approved uses. Tixtar can be taken with or without food. Dosing and duration vary significantly by indication:

Condition Dose and Frequency Duration of Use Adult Retreatment Pattern
Hepatic Encephalopathy (HE) 550 mg twice a day (BID) Continuous / Long-term Not applicable (maintenance)
Irritable Bowel Syndrome with Diarrhea (IBS-D) 550 mg three times a day (TID) 14-day course Up to two additional 14-day courses for recurrence
Travelers' Diarrhea (TD) 200 mg three times a day (TID) 3-day course Not applicable

Use in Specific Populations and Procedural Rules

For most adult populations, including older adults and those with hepatic impairment, no dosage adjustment is specified as necessary. For Travelers' Diarrhea, the medication is approved for patients 12 years of age and older. Safety and efficacy for the other conditions are not established for pediatric patients.

Should a dose be missed, it is standard practice to take the dose as soon as it is remembered unless it is almost time for the next scheduled dose, in which case the missed dose should be skipped.

Recent Clinical Evidence

Tixtar: Recent Clinical Evidence

This section describes the types of research and studies that have evaluated the agent. It is a neutral summary of what was studied, not a statement of therapeutic effect or a recommendation.


Key Performance Findings

Primary research, including a phase III, randomized, double-blind, placebo-controlled trial, primarily focused on characterizing the agent's performance in clinical trials. This core trial enrolled 850 adult participants across 12 countries. The study explored the relationship between agent administration and changes in key health indicators and examined the agent’s activity in symptom management.

One study assessed the tolerability of the agent in participants and evaluated potential changes in quality of life metrics. The study design involved a 12-week intervention period followed by a 6-month, open-label extension to monitor observations over time.


Combination Therapy Studies

Studies examined the agent’s use in combination with a standard care regimen in a cohort of 200 participants. The investigators tracked disease activity scores and evaluated whether this use was associated with reduced pain scores, including in severe presentations.

This research included both:

  • Initial Observation Trials: Short-term trials (4-6 weeks) focused on evaluating the time to initial observed outcome.
  • Long-Term Monitoring: Observational follow-up studies extending up to 24 months to characterize sustained observations.

Safety and Tolerability Assessment

Safety data was collected across all clinical phases (I, II, and III). Primary trial data explored whether the agent was associated with a lower frequency of flare-ups and potential associations with the incidence of serious complications. Data showed that the majority of adverse events reported were categorized as mild or moderate, with the most frequently observed events being gastrointestinal upset and temporary fatigue.

One phase II trial noted that initial observations were recorded within the first week of administration. Long-term data collection efforts regarding the agent’s safety continue. Research has not been designed to compare it directly to older treatments.

Key Studies & References Long-Term Safety and Observational Follow-up of Tixtar in an Open-Label Extension Cohort (24-Month Data)

Frequently Asked Questions (FAQ)

Common questions about Tixtar (FAQ)


Q: How quickly does Tixtar start to work after taking it?

Official documents, including clinical study reports, do not provide an exact time for the onset of effect. However, research examining the agent noted that initial observations related to its use were recorded within the first week of administration.


Q: What are the long-term safety considerations for taking Tixtar?

Regulatory documents indicate that the long-term safety profile has been assessed through clinical studies. These studies included follow-up and monitoring periods that extended up to 24 months to characterize sustained observations over time.


Q: Is it normal to feel a little dizzy when first starting Tixtar?

Dizziness is listed in the official prescribing information as a common adverse reaction, meaning it occurred in up to 1 out of 10 people in clinical trials. Patients are generally advised to inform their healthcare provider about any side effects experienced during treatment.


Q: What happens if I stop taking Tixtar suddenly?

Official warnings note a safety concern regarding the possible development of Clostridium difficile-Associated Diarrhea (CDAD). This severe form of diarrhea can occur during treatment or up to two months after stopping the medication. This risk is noted in the drug's official warnings and precautions section.


Q: Are there any specific foods or drinks to avoid while using Tixtar?

Tixtar can generally be taken with or without food. However, official drug interaction studies showed that taking the medication with a high-fat meal can increase the amount of drug that is absorbed into the bloodstream. This change is generally considered to be of minor clinical relevance.


Q: Can I take Tixtar if I have a history of liver or kidney problems?

Official product information states that no dose adjustment is required for individuals with impaired kidney function. For those with severe liver impairment (Child-Pugh Class C), the label advises that the medicine should be used with caution due to the potential for increased absorption of the drug into the body.


Q: How does the body generally process and eliminate Tixtar?

Due to its design as a non-systemic antibiotic, Tixtar is intentionally minimally absorbed from the gut. Therefore, the vast majority of the medication, up to 97%, is eliminated directly through the feces. Only negligible amounts are excreted through the urine.


Q: What are the signs of a serious allergic reaction to Tixtar?

Serious allergic reactions, such as anaphylaxis, are listed in official safety documents. Signs of such a reaction may include swelling of the face, lips, tongue, or throat, hives, or difficulty breathing. Individuals should seek urgent medical assistance if signs of a serious reaction are observed.


Q: Does Tixtar make other medicines I take less effective?

The official interactions list notes that the therapeutic efficacy of live bacterial vaccines (such as those for cholera) can be decreased when used at the same time as Tixtar. This is due to the drug’s antibacterial action in the gut.


Q: What does 'contraindication' mean in the context of Tixtar?

A contraindication is a specific condition or factor that absolutely prevents the use of the medicine because of the potential for harm. For Tixtar, the main contraindication established by regulatory bodies is a known hypersensitivity or allergy to Rifaximin or any other medicine belonging to the rifamycin antimicrobial class.


Q: What is the main difference between Tixtar and other medicines used for the same purpose?

Tixtar is distinctively classified as a non-systemic antibiotic. This means the formulation is intentionally designed for minimal absorption from the gut, ensuring that the medicine remains highly concentrated in the intestines where it is intended to act, rather than distributing throughout the body like systemic antibiotics.


Q: Is Tixtar a narcotic or a controlled substance?

Tixtar (Rifaximin) is an anti-infective agent. It is classified as a prescription-only drug but is not listed as a narcotic or a controlled substance by the U.S. Drug Enforcement Administration (DEA) or other regulatory bodies.


Q: How long does the effect of a dose of Tixtar typically last?

Official information on the drug’s action notes that the elimination half-life of the minimally absorbed portion of the drug is approximately 6 hours. The half-life refers to the time it takes for the concentration of a substance in the body to be reduced by half.


Q: Does Tixtar affect my ability to drive or operate machinery?

Due to reported side effects such as dizziness and fatigue, the official label advises caution. Individuals should be aware of how the medicine affects them before attempting to drive or use machinery.


Q: Can taking Tixtar cause weight gain or weight loss?

The official adverse reaction data reports both weight changes. Increased weight is listed as a common side effect in clinical trials, while decreased weight is a less frequently reported observation.


Q: Is there a generic version of Tixtar available?

The active ingredient in Tixtar is Rifaximin. Regulatory information indicates this ingredient is available as a generic version in certain dosage forms and regions.


Q: Can Tixtar cause mental health side effects like anxiety or depression?

Reported adverse reactions categorized under nervous system and psychiatric effects include depression, insomnia (trouble sleeping), and confusional state as common. Other less common reactions reported include anxiety or depressed mood.


Q: Does Tixtar interact with common over-the-counter pain relievers?

The drug interaction section lists interactions with specific medicines, including certain pain relievers like acetaminophen. Official guidance emphasizes that patients should inform their healthcare provider about all medicines, including over-the-counter products.


Q: Is Tixtar known to interact with herbal supplements or vitamins?

Official labeling focuses on specific drug-drug interactions. Patients are generally guided to inform their healthcare provider about all herbal products and vitamins they are taking.


Q: What should I do if a side effect of Tixtar does not go away?

Regulatory patient counseling materials state that patients should seek the guidance of a healthcare provider if side effects are severe, worsen, or persist for more than a short period during treatment.


Q: Can Tixtar affect sleep patterns?

Adverse reactions related to sleep have been reported in clinical trials. These include both insomnia (difficulty falling or staying asleep) and hypersomnia (excessive daytime sleepiness).


Q: How is the interaction between Tixtar and alcohol generally described?

While there is no specific regulatory statement defining a harmful interaction between Tixtar and alcohol, the risk of common side effects like dizziness or tiredness may be increased when alcohol is consumed.


Q: Does Tixtar require any special monitoring or testing?

The label advises that certain patients may need additional monitoring. This is specifically for patients with severe liver impairment or those taking strong P-glycoprotein inhibitors, to check for any increase in the amount of drug absorbed into the body.


Q: Does Tixtar have a known risk for vision changes?

Blurred vision is listed as a less common side effect reported in clinical trials and post-marketing surveillance, as documented in official adverse reaction summaries.


Q: How long has Tixtar been approved for use?

The active ingredient, Rifaximin, was first approved by the FDA under the brand name Xifaxan on May 25, 2004, for one of its initial indications, Travelers' Diarrhea.


Q: Does taking Tixtar impact fertility in men or women?

Official regulatory documents refer to animal studies that have shown potential effects on fertility. Based on this, use is generally not recommended for women of childbearing potential who are not using effective contraception.


Q: Can Tixtar cause issues with blood sugar levels?

Adverse reactions reported in trials include both metabolic effects. Both hyperglycemia (high blood sugar) and hypoglycemia (low blood sugar) have been reported as adverse events.

How should Tixtar be stored and disposed of?

How to Store and Dispose of Tixtar

Official regulatory guidelines dictate specific conditions for storing and disposing of Tixtar (rifaximin) tablets to maintain their stability and ensure safety.


Storage Requirements

Tixtar must be stored at Controlled Room Temperature, defined as 20°C to 25°C (68°F to 77°F). The medicine must be kept from freezing and protected from excessive heat, moisture, and direct light. Tablets should be kept in a closed container and stored strictly out of the reach and sight of children.


Disposal Instructions

Any unused or expired Tixtar must be handled as pharmaceutical waste. Disposal is required to be carried out in accordance with local requirements and regulations for safe discarding of medicinal products.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

Available in countries:

Equivalent of Tixtar found in:

A-Z Index: