Rifamax
Rifamax Uses, Dosage, Side Effects, Food Interaction and all others data.
Rifamax is a non-aminoglycoside semi-synthetic antibacterial derived from rifamycin SV. It inhibits bacterial RNA synthesis by binding to the bacterial DNA-dependent RNA polymerase and has antibacterial activity against Escherichia coli (E. coli).
Rifamax is a structural analog of rifampin and a non-systemic, gastrointestinal site-specific antibiotic. This non-systemic property of the drug is due to the addition of a pyridoimidazole ring, which renders it non-absorbable. Rifamax acts by inhibiting bacterial ribonucleic acid (RNA) synthesis and contributes to restore intestinal microflora imbalance. Other studies have also shown rifaximin to be an pregnane X receptor (PXR) activator. As PXR is responsible for inhibiting the proinflammatory transcription factor NF-kappa B (NF-κB) and is inhibited in inflammatory bowel disease (IBD), rifaximin was proven to be effective for the treatment of IBS-D.
| Trade Name | Rifamax |
| Availability | Prescription only |
| Generic | Rifaximin |
| Rifaximin Other Names | Rifaxidin, Rifaximin, Rifaximina, Rifaximine, Rifaximinun |
| Related Drugs | ciprofloxacin, dicyclomine, sulfamethoxazole / trimethoprim, Bactrim, loperamide, lactulose, Bentyl, hyoscyamine, Xifaxan, Imodium |
| Weight | 200mg, 550mg |
| Type | Tablet |
| Formula | C43H51N3O11 |
| Weight | Average: 785.8785 Monoisotopic: 785.352359489 |
| Groups | Approved, Investigational |
| Therapeutic Class | Miscellaneous Antibiotics |
| Manufacturer | Incepta Pharmaceuticals Ltd, Incepta Pharmaceuticals Limited |
| Available Country | India, Bangladesh |
| Last Updated: | September 19, 2023 at 7:00 am |
Uses
Acute infectious diarrhoea including travelers diarrhoea, Diarrhoea predominant Irritable Bowel Syndrome (IBS-D), Hepatic Encephalopathy (H.E.)
Rifamax is also used to associated treatment for these conditions: Bacterial Infections, Clostridium difficile infection recurrence, Hepatic Encephalopathy (HE), Irritable Bowel Syndrome (IBS), Traveler's Diarrhea
How Rifamax works
Rifamax acts by inhibiting RNA synthesis in susceptible bacteria by binding to the beta-subunit of bacterial deoxyribonucleic acid (DNA)-dependent ribonucleic acid (RNA) polymerase enzyme. This binding blocks translocation, which stops transcription.
Dosage
Rifamax dosage
Acute Infectious Diarrhoea including Travelers’ Diarrhoea: 200 mg three times daily for 3 days.
Diarrhoea predominant Irritable Bowel Syndrome (IBS-D): 550 mg three times daily for 14 days.
Hepatic Encephalopathy (H.E.): 550 mg twice daily
Side Effects
Common side effects are nausea, vomiting, abdominal pain, flatulence, headache and dizziness.
Toxicity
LD50 > 2 g/kg (orally, in rats)
Precaution
Pregnancy and lactation. Caution in severe hepatic impairment (Child-Pugh class C). Not effective against diarrhoea caused by pathogen other than E. coli ; or diarrhoea complicated by fever and/or blood in the stool. Prolonged use may result in Clotridum difficile-associated diarrhoea. Severe hepatic impairment (Child-pugh class C).
Interaction
Although In vitro studies demonstrated the potential of Rifamax to interact with cytochrome P450 (CYP3A4), a clinical drug-drug interaction study demonstrated that Rifamax did not significantly affect the pharmacokinetics of midazolam. An additional clinical drug-drug interaction study showed no effect of Rifamax on the presystemic metabolism of an oral contraceptive containing ethinyl estradiol and norgestimate. Therefore, clinical interactions with drugs metabolized by human cytochrome P450 isozymes are not expected.
Food Interaction
- Take with or without food. Fatty meals may increase the systemic AUC of rifaximin, but do not impact Cmax. Rifamax is an antibacterial used for local action in the gastrointestinal tract; therefore, changes in systemic exposure may not significantly impact efficacy.
Rifamax Drug Interaction
Unknown: aspirin, lorazepam, amoxicillin / clavulanate, diphenhydramine, duloxetine, metronidazole, furosemide, pregabalin, polyethylene glycol 3350, esomeprazole, acetaminophen, pantoprazole, acetaminophen, cyanocobalamin, ascorbic acid, cholecalciferol, alprazolam, ondansetron, sertraline, cetirizine
Rifamax Disease Interaction
Elimination Route
Low absorption in both the fasting state and when administered within 30 minutes of a high-fat breakfast.
Half Life
Approximately 6 hours.
Elimination Route
In a mass balance study, after administration of 400 mg 14C-rifaximin orally to healthy volunteers, of the 96.94% total recovery, 96.62% of the administered radioactivity was recovered in feces almost exclusively as the unchanged drug and 0.32% was recovered in urine mostly as metabolites with 0.03% as the unchanged drug.Rifamax accounted for 18% of radioactivity in plasma. This suggests that the absorbed rifaximin undergoes metabolism with minimal renal excretion of the unchanged drug
Pregnancy & Breastfeeding use
Pregnancy Category C. There are no adequate and well-controlled studies in pregnant women. Rifamax should be used during pregnancy only if the potential benefit outweighs the potential risk to the fetus.
Use in Lactation: It is not known whether Rifamax is excreted in human milk. Because many drugs are excreted in human milk and because of the potential for adverse reactions in nursing infants from Rifamax, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.
Contraindication
Rifamax is contraindicated in patients with a hypersensitivity to Rifamax, or any of the Rifamycin antimicrobial agents, or any of the components of Rifamax.
Special Warning
Use in Children: The safety and effectiveness of Rifamax 200 mg in pediatric patients with travelers’ diarrhoea less than 12 years of age have not established.The safety and effectiveness of Rifamax 550 mg for hepatic encephalopathy have not been established in patients <18 years of age.
Use in geriatric patients: Clinical studies of Rifamax tablets did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently than younger subjects.
Use in Renal Insufficient Patients:The pharmacokinetics of Rifamax in patients with impaired renal function has not been studied.
Use in Hepatic Insufficient Patients:No dosage adjustment with Rifamax is necessary due to its limited systemic absorption. Nonetheless, caution should be exercised when Rifamax is administered to patients with severe hepatic impairment.
Acute Overdose
No specific information is available on the treatment of over dosage with Rifamax. In case of over dosage, discontinue Rifamax, treat symptomatically and institute supportive measures as required.
Storage Condition
Store at 20-25° C; excursions permitted to 15-30° C.
Innovators Monograph
You find simplified version here Rifamax
Rifamax contains Rifaximin see full prescribing information from innovator Rifamax Monograph, Rifamax MSDS, Rifamax FDA label
FAQ
What is Rifamax used for?
Rifamax is used to treat traveler's diarrhea that is caused by a bacteria called Escherichia coli. It is also used to prevent hepatic encephalopathy, which is a condition that occurs when your liver does not work normally.Rifamax is also used to treat irritable bowel syndrome with diarrhea.
How safe is Rifamax?
Rifamax is safe and well tolerated for long-term maintenance of remission from overt hepatic encephalopathy.
How does Rifamax work?
Rifamax treats traveler's diarrhea and irritable bowel syndrome by stopping the growth of the bacteria that cause diarrhea. Rifamax treats hepatic encephalopathy by stopping the growth of bacteria that produce toxins and that may worsen liver disease.
What are the common side effects of Rifamax?
Common side effects of Rifamax are include:
- Gas (flatulence)
- Headache
- Feeling as if your bowels are not completely emptied
- Feeling you need to urgently empty your bowels
- Abdominal or stomach pain
- Nausea
- Constipation
- Fever
- Vomiting
- Bloating
- Dizziness
- Tired feeling
- Swelling in your hands, feet, or torso
Is Rifamax safe during pregnancy?
There are no adequate and well controlled studies in pregnant women.Rifamax tablets should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Is Rifamax safe during breastfeeding?
Rifamax is poorly absorbed orally and used only for gastrointestinal infections. It is not likely to reach the breastmilk or bloodstream of the infant or cause any adverse effects in breastfed infants after maternal use.
When Is the best taken of Rifamax?
Rifamax usually 2 times a day (every 12 hours).Take this medication at the same time(s) every day.
Can I take Rifamax on an empty stomach?
Rifamax should be taken on an empty stomach.
Should Rifamax be taken with food?
You may take this medicine with or without food.
Is Rifamax strong antibiotic?
Rifamax is a gastrointestinal-selective antibiotic with a broad spectrum of antimicrobial activity, an excellent safety profile, minimal drug interactions, and negligible impact on the intestinal microbiome.
How fast does Rifamax work?
After just two weeks of treatment, relief lasted for up to 6 months.
Who should not take Rifamax?
You should not take Rifamax if you are allergic to Rifamax. Tell your doctor if you have ever had.Tell your doctor if you are pregnant or breastfeeding.Rifamax should not be given to a child younger than 12 years old.
Is Rifamax safe for liver?
Rifamax could theoretically prevent SBP in patients with liver cirrhosis by reducing gut bacteria.
Can Rifamax help constipation?
The antibiotic Rifamax is used to treat non-constipated irritable bowel syndrome (IBS).
How long can I take Rifamax?
You may take Rifamax with or without food. For travelers' diarrhea, Rifamax is usually taken for only 3 days.
Is Rifamax safe for kidneys?
While the effects of Rifamax have been shown to be protective against acute kidney injury and hepatorenal syndrome in alcohol-induced cirrhosis, its long-term effects on the renal function of other cirrhotic patients are unknown.
What happens if I miss a dose of Rifamax?
Take Rifamax as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.
What should I avoid while taking Rifamax?
Antibiotic medicines can cause diarrhea, which may be a sign of a new infection. If you have diarrhea that is watery or bloody, call your doctor before using anti-diarrhea medicine.
How many Rifamax can Rifamax take in a day?
Adults and children 12 years of age and older 200 milligrams (mg) three times a day for 3 days. Children younger than 12 years of age.Use and dose must be determined by your doctor.
