Rifakem-550 (Rifaximin 550mg)

Rifakem-550 general information

What is Rifakem-550 used for?

Rifakem 550 is an antibiotic used to treat hepatic encephalopathy (HE) to prevent its recurrence, where other treatments have failed or are contraindicated.  HE is a neuropsychiatric condition in which there is a loss of brain function due to liver damage, such as cirrhosis.  This results in a build-up of toxins like ammonia in the blood, which causes symptoms including confusion, difficulty thinking, loss of fine hand movements, behaviour changes and a musty or sweet smelling breath.  It is thought that an imbalance of the intestinal microbiota (good versus bad bacteria) with a higher proportion of pathogenic bacteria, may contribute to the pathogenesis of several diseases including liver cirrhosis.  Rifakem-550 is effective against a wide range of intestinal bacteria, including those like Streptococcus salivarius that produce ammonia.  Ammonia is a toxin that a healthy liver would convert into urea which is then excreted in the urine, but in a damaged liver this process is impaired.  Rifakem tablets 550mg help restore the balance in the composition of intestinal bacteria and reduce risk of HE and its recurrence¹.  Rifakem-550 cannot be used to treat other infections as it is not absorbed into the blood and therefore, only acts locally in the gastrointestinal tract to kill local bacteria.   

How does Rifakem-550 work?

Rifakem tablets 550mg contain rifaximin, a locally acting antibiotic belonging to the rifamycin class of antibiotics.  It is a non-systemic antibiotic, which means it acts locally in the intestines and is not absorbed into the circulation.  Rifaximin in Rifakem 550 works by binding to the bacterial enzyme DNA-dependent RNA polymerase and this action inhibits bacterial RNA synthesis.  This prevents RNA transcription and thereby the production of bacterial proteins, which inhibits growth of the bacteria.  Rifaximin in Rifakem 550 is effective against bacteria that break down proteins in the intestines by the process of deamination resulting in ammonia production, reducing the high blood levels of ammonia that contribute to the pathogenesis of hepatic encephalopathy^2-5.

What does Rifakem-550 contain?

Rifakem tablets contain the active ingredient rifaximin 550mg, a locally acting antibiotic used to prevent the recurrence of hepatic encephalopathy where other treatments have failed or are contraindicated.  

Rifakem-550 for hepatic encephalopathy

Rifakem tablets 550mg contain rifaximin, a locally acting antibiotic that is used to treat hepatic encephalopathy to prevent its recurrence where other treatments have failed or are contraindicated.  Hepatic encephalopathy is a neuropsychiatric condition in which there is a loss of brain function due to liver damage, such as cirrhosis.  This results in a build-up of toxins in the blood, such as ammonia which causes symptoms including confusion, difficulty thinking, loss of fine hand movements, behaviour changes and a musty or sweet smelling breath.  Rifaximin in Rifakem 550 is effective against bacteria that break down proteins in the intestines by deamination resulting in ammonia production.  A healthy liver would normally convert ammonia into urea which is then excreted in the urine, but in a damaged liver this process is impaired.  Rifaximin in Rifakem-550 inhibits growth of ammonia producing bacteria, reducing the high blood levels of ammonia that contribute to the pathogenesis of hepatic encephalopathy.

What are the side effects of Rifakem-550?

The most commonly reported side effects when taking Rifakem-550 include dizziness, headache, fever, fatigue, abdominal pain, constipation, defecation urgency, diarrhoea, flatulence, bloating and distension, nausea and vomiting, oedema, rash.  Rifakem-550 can result in Clostridium difficile-associated diarrhoea (CDAD), which is a more serious form of diarrhoea ranging in severity from mild to life-threatening and is due to the changes in intestinal flora that happens when taking antibiotics. 

When should Rifakem-550 not be used?

You should not use Rifakem-550 if you:

• are allergic to rifaximin or any ingredients in Rifakem-550
• are pregnant or are breastfeeding
• have severe liver disease, without discussion with your doctor
• have any form of intestinal obstruction
• are taking medicines that interact with Rifakem-550, including other rifamycin antibiotics and the immunosuppressant ciclosporin.  Rifakem-550 reduces the effect of warfarin

How should Rifakem-550 be taken?

For hepatic encephalopathy you should take your Rifakem-550 swallowed whole with a glass of water with or without food twice daily for 6 months.  The dose you take should be as recommended by your doctor.  You should only continue to take your Rifakem-550 beyond 6 months based on your doctor’s recommendation, after evaluation by your doctor of how well you are responding and any side effects you are experiencing.  

How long should you take Rifakem-550?

You should only continue to take your Rifakem-550 beyond 6 months based on your doctor’s recommendation, after evaluation by your doctor of how well you re responding and any side effects you are experiencing. 

Missed dose of Rifakem-550

If you miss a dose of Rifakem-550 take it as soon as you remember, unless it is time to take the next dose, then skip the missed dose.  Do not take a double dose.

How should Rifakem-550 be stored?

You should store your Rifakem-550 below 25°C in a cool dry place. 

References

1. Ponziani FR, Gerardi V, Pecere S, D'Aversa F, Lopetuso L, Zocco MA, Pompili M, Gasbarrini A. Effect of rifaximin on gut microbiota composition in advanced liver disease and its complications. World J Gastroenterol. 2015 Nov 21;21(43):12322-33.
2. Zeng X, Tang XJ, Sheng X, Ni W, Xin HG, et al. Does low-dose rifaximin ameliorate endotoxemia in patients with liver cirrhosis: a prospective study. J Dig Dis 2015 Nov;16(11):665-74.
3. Shayto RH, Abou Mrad R, Sharara AI. Use of rifaximin in gastrointestinal and liver diseases. World J Gastroenterol. 2016 Aug 7;22(29):6638-51.
4. Peleman C, Camilleri M. Rifaximin, Microbiota Biology, and Hepatic Encephalopathy. Clin Transl Gastroenterol 2016 Oct 6;7(10):
5. Iadevaia MD, Del Prete A, Cesaro C, Gaeta L, Zulli C, Loguercio C.  Rifaximin in the treatment of hepatic encephalopathy. Hepat Med 2011; 3: 109–117.