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Nitazoxanide
Systematic (IUPAC) name
[2-[(5-nitro-1,3-thiazol-2-yl)carbamoyl]phenyl]ethanoate
Identifiers
CAS number 55981-09-4
ATC code P01AX11
PubChem 41684
DrugBank APRD00558
Chemical data
Formula C 12H9N3O5S 
Mol. mass 307.283 g/mol
Pharmacokinetic data
Bioavailability  ?
Protein binding 99%
Metabolism Hydrolyzed to tizoxanide
Half life  ?
Excretion Renal, biliary and fecal
Therapeutic considerations
Pregnancy cat. B(US)
Legal status -only (US)
Routes Oral (tablets and suspension)
 Yes check.svgY(what is this?)  (verify)

Nitazoxanide, also known by the brand names Alinia and Annita (and by Daxon, Dexidex, Kidonax, Pacovanton and Paramix in Mexico, by Nitax, Zox, Nitazox and Toza in Bangladesh) is a synthetic nitrothiazolyl-salicylamide derivative and an antiprotozoal agent.

Nitazoxanide is a light yellow crystalline powder. It is poorly soluble in ethanol and practically insoluble in water.

Contents

History

Nitazoxanide was originally discovered in the 1980s by Jean François Rossignol at the Pasteur Institute. Initial studies demonstrated activity versus tapeworms. In vitro studies demonstrated much broader activity. Dr. Rossignol co-founded Romark Laboratories, with the goal of bringing nitazoxanide to market as an anti-parasitic drug. Initial studies in the USA were conducted in collaboration with Unimed Pharmaceuticals, Inc. (Marietta, GA) and focused on development of the drug for treatment of cryptosporidiosis in AIDS. Controlled trials began shortly after the advent of effective anti-retroviral therapies. The trials were abandoned due to poor enrollment and the FDA rejected an application based on uncontrolled studies.

Rather than abandon their efforts, Romark launched an impressive series of controlled trials. No other agent has proven efficacy in the treatment of cryptosporidiosis. However, a placebo-controlled study of nitazoxanide in cryptosporidiosis demonstrated significant clinical improvement in adults and children with mild illness. Among malnourished children in Zambia with chronic cryptosporidiosis, a three-day course of therapy not only led to clinical and parasitologic improvement, but also improved survival. In Zambia and in a study conducted in Mexico, nitazoxanide was not successful in the treatment of cryptosporidiosis in advanced infection with human immunodeficiency virus at the doses used. However, it was effective in patients with higher CD4 counts. Also, higher doses seem to have some effect in uncontrolled and unpublished studies. In treatment of giardiasis, nitazoxanide was superior to placebo and comparable to metronidazole. Nitazoxanide was successful in the treatment of metronidazole-resistant giardiasis. Studies have suggested efficacy in the treatment of cyclosporiasis, isosporiasis, and amebiasis.[1]

Mechanism of action

The anti-protozoal activity of nitazoxanide is believed to be due to interference with the pyruvate:ferredoxin oxidoreductase (PFOR) enzyme dependent electron transfer reaction which is essential to anaerobic energy metabolism.

It has also been shown to have activity against influenza A virus.[2] The mechanism appears to be by selectively blocking the maturation of the viral hemagglutinin at a stage preceding resistance to endoglycosidase H digestion. This impairs hemagglutinin intracellular trafficking and insertion of the protein into the host plasma membrane.

Uses

Nitazoxanide is a first-line choice for the treatment of illness caused by Cryptosporidium parvum or Giardia lamblia infection in immunocompetent adults and children, and is an option to be considered in the treatment of illness caused by other protozoa and/or helminths.[3]

It is used for the treatment of infectious diarrhea caused by Cryptosporidium parvum[4] and Giardia lamblia[5] in patients 1 year of age and older.

Nitazoxanide is currently in Phase II clinical trials for the treatment of hepatitis C, in combination with peginterferon alfa-2a and ribavirin.[6][7]

A randomised double-blind placebo-controlled study published in 2006, with a group of 38 young children (Lancet, vol 368, page 124-129)[8] concluded that a 3-day course of nitazoxanide significantly reduced the duration of rotavirus disease in hospitalized pediatric patients. Dose given was "7.5 mg/kg twice daily" and the time of resolution was "31 hours for those given nitazoxanide compared with 75 hours for those in the placebo group." It is to be noted that rotavirus is the most common infectious agent associated with diarrhea in the pediatric age group worldwide.[9]


TREATMENT OF CHRONIC HEPATITIS B

Nitazoxanide alone has shown preliminary evidence of efficacy in the treatment of chronic hepatitis B over a one year course of therapy[10]. Nitazoxanide 500 mg twice daily resulted in a decrease in serum HBV DNA in all of 4 HBeAg-positive patients, with undetectable HBV DNA in 2 of 4 patients, loss of HBeAg in 3 patients, and loss of HBsAg in one patient. Seven of 8 HBeAg-negative patients treated with nitazoxanide 500 mg twice daily had undetectable HBV DNA and 2 had loss of HBsAg.Additionally, nitazoxanide monotherapy in one case and nitazoxanide plus adefovir in another case resulted in undetectable HBV DNA, loss of HBeAg and loss of HBsAg[11]. These preliminary studies showed a higher rate of HBsAg loss than any currently licensed therapy for chronic hepatitis B.The similar mechanism of action of interferon and nitazoxanide suggest that stand-alone nitazoxanide therapy or nitazoxanide in concert with nucleos(t)ide analogs have the potential to increase loss of HBsAg, which is the ultimate end-point of therapy. A formal phase Ⅱ study is being planned for 2009.(World Journal of Gastroenterology 2009 April 21, Emmet B Keeffe MD, Professor,Jean-François Rossignol The Romark Institute for Medical Research, Tampa)

Teran et al. conducted a study at the Pediatric Center Albina Patinö, a reference hospital in the city of Cochabamba, Bolivia, from August 2007 to February 2008. The study compared nitazoxanide and probiotics in the treatment of acute rotavirus diarrhea. They found Small differences in favor of nitazoxanide in comparison with probiotics and concluded that nitazoxanide is an important treatment option for rotavirus diarrhea.[10]

Romark Laboratories has announced encouraging results from international Phase I and II clinical trials evaluating a controlled release version of nitazoxanide in the treatment of chronic hepatitis C virus infection. The company used 675 mg and 1,350 mg twice daily doses of controlled release nitazoxanide Controlled release nitazoxanide showed favorable safety and tolerability throughout the course of the study, with mild to moderate adverse events. Primarily GI-related adverse events were reported.[11]

Lateef et al. conducted a study in India that evaluated the effectiveness of nitazoxanide in the treatment of beef tapeworm (Taenia saginata) infection. They concluded that nitazoxanide is a safe, effective, inexpensive, and well-tolerated drug for the treatment of niclosamide- and praziquantel-resistant beef tapeworm (Taenia saginata) infection.[12]

A retrospective review of charts of patients treated with nitazoxanide for trichomoniasis by Michael Dan and Jack D. Sobel demonstrated negative result. They reported three case studies; two of which with metronidazole-resistant infections. In Case 3, they reported the patient to be cured with high divided dose tinidazole therapy. They used a high dosage of the drug (total dose, 14–56 g) than the recommended standard dosage (total dose, 3 g) and observed a significant adverse reaction (poorly tolerated nausea) only with the very high dose (total dose, 56 g). Though the output they got is in favor of safety of the drug but their experience was really disappointing in the treatment of trichomoniasis with nitazoxanide.[13]

Adverse effects

Side effects are mostly gastrointestinal, and include abdominal pain, vomiting, headache, nausea and diarrhea.

In the clinical trials no serious adverse events were reported. No serious adverse events were reported in the prescribing information of the parent company.[14]

Pharmacokinetics

Nitazoxanide is a prodrug.

Following oral administration, it is rapidly hydrolyzed to its active metabolite, tizoxanide,[15] which is 99% protein bound. Peak concentrations are observed 1–4 hours after administration.

It is excreted in the urine, bile and feces.

Dosage forms

Nitazoxanide is available in two oral dosage forms - tablet (500 mg) and oral suspension (100 mg per 5 ml when reconstituted).

References

  1. ^ Am. J. Trop. Med. Hyg., 68(4), 2003, pp. 382-383
  2. ^ Rossignol JF, La Frazia S, Chiappa L, Ciucci A, Santoro MG. Thiazolides, a new class of anti-influenza molecules targeting viral hemagglutinin at the post-translational level. J Biol Chem. 23284(43):29798-29808
  3. ^ Vanessa R. Anderson and Monique P. Curram; Nitazoxanide A Review of its Use in the Treatment of Gastrointestinal Infections; Drugs 2007; 67 (13)
  4. ^ Rossignol JF, Ayoub A, Ayers MS (July 2001). "Treatment of diarrhea caused by Cryptosporidium parvum: a prospective randomized, double-blind, placebo-controlled study of Nitazoxanide". J. Infect. Dis. 184 (1): 103–6. doi:10.1086/321008. PMID 11398117. http://www.journals.uchicago.edu/cgi-bin/resolve?JID010133.  
  5. ^ Abboud P, Lemée V, Gargala G, et al. (June 2001). "Successful treatment of metronidazole- and albendazole-resistant giardiasis with nitazoxanide in a patient with acquired immunodeficiency syndrome". Clin. Infect. Dis. 32 (12): 1792–4. doi:10.1086/320751. PMID 11360222. http://www.journals.uchicago.edu/cgi-bin/resolve?CID000801.  
  6. ^ Medical News Today (August 16, 2007). "Romark Initiates Clinical Trial Of Alinia For Chronic Hepatitis C In The United States". Press release. http://www.medicalnewstoday.com/articles/79780.php. Retrieved 2007-10-11.  
  7. ^ Franciscus, Alan (October 2, 2007). "Hepatitis C Treatments in Current Clinical Development". HCV Advocate. http://www.hcvadvocate.org/hepatitis/hepC/HCVDrugs.html. Retrieved 2007-10-11.  
  8. ^ . doi:10.1016/S0140-6736(06)68852-1.  
  9. ^ (Article in press, International Journal of Infectious Disease, 2008)
  10. ^ International Journal of Infectious Diseases (2009) 13, 518—523; doi:10.1016/j.ijid.2008.09.014
  11. ^ http://drugdiscovery.pharmaceutical-business-review.com/news/romark_reports_promising_data_from_hepatitis_c_virus_study_200209 (accessed on July 14, 2009)
  12. ^ International Journal of Infectious Diseases (2008) 12, 80—82; doi:10.1016/j.ijid.2007.04.017
  13. ^ Sexually Transmitted Diseases, October 2007, Vol. 34, No. 10, p.813–814; DOI: 10.1097/NMD.0b013e31802f5d9a
  14. ^ Romark Pharmaceuticals. Alinia. (Nitazoxanide). http://www.romark.com
  15. ^ Korba BE, Montero AB, Farrar K, et al. (January 2008). "Nitazoxanide, tizoxanide and other thiazolides are potent inhibitors of hepatitis B virus and hepatitis C virus replication". Antiviral Res. 77 (1): 56–63. doi:10.1016/j.antiviral.2007.08.005. PMID 17888524. http://linkinghub.elsevier.com/retrieve/pii/S0166-3542(07)00397-X.  

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