Rifaximin

Rifaximin is an antibiotic used to treat bacterial infections in the gut and to prevent a serious liver-related complication called hepatic encephalopathy.

Rifaximin is commonly used for:

• Traveller's diarrhoea: Treats acute watery diarrhoea caused by non-invasive strains of Escherichia coli (E. coli) bacteria, commonly acquired when travelling to regions with different sanitation standards.
• Hepatic encephalopathy (prevention): Reduces the risk of recurrence of hepatic encephalopathy a condition where toxins build up in the blood due to liver disease, affecting brain function. Symptoms include confusion, memory problems, and personality changes.
• Irritable bowel syndrome with diarrhoea (IBS-D): Used in some cases to reduce bloating and diarrhoea associated with IBS, particularly when related to bacterial overgrowth in the gut.
• Small intestinal bacterial overgrowth (SIBO): May be used in some cases to help reduce the excessive growth of bacteria in the small intestine, which causes bloating, flatulence, and diarrhoea.

• Feeling or being sick
• Stomach ache or bloating/swelling
• Diarrhoea
• Depressed mood
• Dizziness
• Headache
• Shortness of breath
• Accumulation of fluid in the abdomen
• Rash or itching
• Muscle cramps
• Joint pain
• Swelling of ankles, feet or fingers

• Rifaximin works by blocking the production of RNA that bacteria need to survive and reproduce, effectively stopping the bacterial infection.
• It belongs to the rifamycin class of antibiotics and is a semi-synthetic derivative of rifampicin. Rifaximin targets an enzyme in bacteria called RNA polymerase (specifically the beta subunit). This enzyme is responsible for a process called transcription the step in which bacteria read their genetic instructions to produce proteins essential for their growth and survival.
• By binding to RNA polymerase, Rifaximin prevents bacteria from reading their DNA correctly, thereby inhibiting RNA synthesis. Without these proteins, bacteria cannot grow or multiply, allowing the body to clear the infection.
• A key feature of Rifaximin is that it is very poorly absorbed from the gut into the bloodstream. This means it concentrates its action in the intestines, making it highly effective for gut infections whilst minimising systemic effects on the rest of the body. This localised activity also reduces the disruption to beneficial bacteria elsewhere in the body.