Nitazoxanide

Absorption

The relative bioavailability of the suspension compared to the tablet was 70%. When administered with food the AUC and Cmax increased by two-fold and 50%, respectively, for the tablet and 45 to 50% and ≤ 10%, respectively, for the oral suspension .

Toxicity

Data on nitazoxanide overdosage is not available . In studies in rodents and dogs, the oral LD50 was higher than 10,000 mg/kg. One-time oral doses of up to 4000 mg nitazoxanide have been given to healthy adult volunteers without severe adverse effects. Gastric lavage may be appropriate soon after oral administration if overdose occurs. Supportive and symptomatic treatment should also be administered .
According to previous studies , less than 1% of the patients age 12 years and older participating in clinical trials with NTZ suffered from the following adverse effects: Systemic: asthenia, fever, pain, allergic reaction, pelvic pain, back pain, chills, fever, flu-like syndrome. Central Nervous System: dizziness, somnolence, insomnia, tremor, hypesthesia. Gastrointestinal System: vomiting, dyspepsia, anorexia, flatulence, constipation, dry mouth, thirst. Urogenital System: discolored urine, dysuria, amenorrhea, metrorrhagia, kidney pain, edema labia. Metabolic & Nutrition: increased SGPT. Hemic & Lymphatic Systems: anemia, leukocytosis. Skin: rash, pruritus. Special Senses: eye discoloration, ear ache. Respiratory System: epistaxis, lung disease, pharyngitis. Cardiovascular System: tachycardia, syncope, hypertension. Muscular System: myalgia, leg cramps, spontaneous bone fracture.

Description

Nitazoxanide (NT Z) has been approved as an orphan drug for the treatment of diarrhea in children (age, 1–11 years) and is associated with giardiasis, but it also is approved for diarrhea caused by crytosporidiosis in patients with AIDS. Crytosporidiosis is a protozoal infection caused by Cryptosporidi um parvum. The condition is uncommon in healthy individuals but can be life-threatening in immunosuppressed patients and those with HIV infections.

The Uses of Nitazoxanide

Nitazoxanide has been used:

• to test its anti-viral activity against chikungunya virus
• as an antiprotozoal agent to test its effect on cell viability in various cancer cell lines
• to test its effect on human cytomegalovirus (HCMV) infected human fibroblast HFF cells

Background

Nitazoxanide belongs to the class of drugs known as thiazolides. Nitazoxanide (NTZ) is a broad-spectrum anti-infective drug that markedly modulates the survival, growth, and proliferation of a range of extracellular and intracellular protozoa, helminths, anaerobic and microaerophilic bacteria, in addition to viruses. This drug is effective in the treatment of gastrointestinal infections including Cryptosporidium parvum or Giardia lamblia in healthy subjects. It is generally well tolerated. Nitazoxanide is a first-line, standard treatment for illness caused by C. parvum or G. lamblia infection in healthy (not immunosuppressed) adults and children and may also be considered in the treatment of illnesses caused by other protozoa or helminths . Recently, this drug has been studied as a broad-spectrum antiviral agent due to its ability to inhibit the replication of several RNA and DNA viruses .

Indications

For the treatment of diarrhea in adults and children caused by the protozoa Giardia lamblia, and for the treatment of diarrhea in children caused by the protozoan, Cryptosporidium parvum .
Nitazoxanide has not been shown to be superior to placebo medication for the management of diarrhea caused by Cryptosporidium parvum in patients with HIV/immunodeficiency .

What are the applications of Application

Nitazoxanide is an antiprotozoal and antihelmintic

Pharmacokinetics

The general effect of this medication is the prevention of microbe activity through disruption of important energy pathways for survival and proliferation . Nitazoxanide exhibits antiprotozoal activity by interfering with the pyruvate ferredoxin/flavodoxin oxidoreductase dependent electron transfer reaction, an essential reaction need for anaerobic energy metabolism of various microorganisms. Sporozoites of Cryptosporidium parvum and trophozoites of Giardia lamblia are therefore inhibited, relieving symptoms of diahrrea . Interference with the PFOR enzyme-dependent electron transfer reaction may only be one of the many pathways by which nitazoxanide exhibits antiprotozoal activity .

Metabolism

The active metabolite of this drug is tizoxanide (desacetyl-nitazoxanide). The initial reaction in the metabolic pathway of Nitazoxanide is hydrolysis to tizoxanide, followed by conjugation, primarily by glucuronidation to tizoxanide glucuronide.
The oral suspension bioavailability of this drug is not equivalent to that of the oral tablets. Compared to the to the tablet, the bioavailability of the suspension was 70% .
When administered with food, the AUCt of tizoxanide and tizoxanide glucuronide in plasma is increased to almost two-fold and the maximum concentration is increased by almost 50% compared to when ingested without food .
When the oral suspension was ingested with food, the AUC of tizoxanide and tizoxanide glucuronide increased by approximately 50% and the Cmax increased by less than 10% .