Nitazoxanide for the treatment of intestinal protozoan and helminthic infections in Mexico

TRANSACTIONS

Nitazoxanide in Mexico

OFTHE

ROYAL

SOCIETY

OFTROPICAL

for the treatment

MEDICINE

of intestinal

AND HYGIENE

protozoan

(1997) 91,701-703

and helminthic

701

infections

Rati Romero Cabello1y2, Lilia Robert Guerrerol, Maria de1 Rocio Mufi6z Garcia2 and Albert0 Geyne Cruzl ‘Department of Microbiology and Parasitology, Faculty of Medicine, National Autonomous University of Mexico, Mexico DE Mexico; 2Department of Infectious Disease, General Hospital of Mexico, Mexico DE Mexico Abstract A study to evaluate the efficacy and safety of nitazoxanide as a single agent for the treatment of a broad spectrum of mixed parasitic infections, both protozoa and helrninths, was conducted at a primary school in San Pedro Toliman, Queretaro, Mexico. Three faecal samples from 1824 adults and children were screened for the presence of oocysts, cysts, trophozoites, eggs or larvae of intestinal protozoa or helminths. Two hundred and forty-six adults and children infected with at least one protozoan and 2 helminths were given 75 mg/kg of nitazoxanide (500 mg to adults and 200 mg to children less than 12 years old) every 12 h for 3 consecutive days. Faecal samples were examined on days 6,7,8, 13, 14 and 15 4 1) following initiation of treatment, using formalin-ether concentration and Kato-Katz egg counting. Treatment with nitazoxanide was 71-100% effective in eliminating evidence of infection withEntamoeba histolyticalE. dispar, Giardia duodenalis, Blastocystis hominis, Isospora belli, Enterobius vermicularis, Ascaris lumbricoides, Trichuris trichiura and Hymenolepis nana. Haematology and clinical chemistry values obtained before and after treatment remained unaffected by nitazoxanide. The drug was well tolerated, with only 15 patients (6.1%) reporting mild abdominal pain that lasted less than 24 h. intestinal parasitosis, Entamoeba histolytica, Entamoeba &par, Giardia duodenal& Blastocystishomini, Isospora belli, Enterobizlsvermicularis, Ascaris lumbricoides,Trichuris trichiura, Hymenolepis nana, chemotherapy, nitazoxanide Keywords:

Introduction Nitazoxanide, yl) benzamide],

[2-(acetolyloxy)-N-(5-nitro-2&iazola 5-nitrothiazole derivative (ROSSIGNOL & CAVIER, 1975), has shown a broad spectrum of activity in vitro against coccidian and flagellate protozoa, amoebae, nematodes, cestodes and trematodes in animal studies (EUZBBY et al., 1980; CAVIER & ROSSIGNOL, 1982). It is also effective against anaerobic bacteria and some aerobic bacteria, such as Streptococcus species and metronidazole-resistant Helicobacter pylon’ (see DUBREUIL et al.. 1996). This unusual suectrum of activity has stimulated human clinical testmg for the treatment of intestinal protozoan and helminthic infections. During a phase I clinical study, nitazoxanide was given as a single 500 mg oral dose to 6 healthy male volunteers. Nitazoxanide was not detected in the plasma but its desacetyl derivative, tizoxanide, reached a mean C max of 1.9 l@mL at a T,,, of 2-6 h. The terminal halflife of tizoxanide in plasma ranged from 1.03 to 1.6 1 h. Tizoxanide was found to be highly bound to plasma proteins (Fb>97% by ultrafiltration). Nitazoxanide was not detectable in urine. Five percent of the dose was recovered as tizoxanide and 3% as salicyluric acid over 72 h (STOCKIS et al., 1996). A clinical study of nitazoxanide in 24 hospital patients in Mali indicated that nitazoxanide was effective at eradicating Cyptosporidium parvum infections in patients diagnosed with acquired immune deficiency syndrome (AIDS) as well as other common protozoa such as Entamoeba histolyticalE. dispar, Giardia duoa’enalis (=G. lamblia) and Isospora belli following treatment with 500 mg twice daily for 7 consecutive days (DOUMBO et al., 1997). Another study of 40 patients in France showed that single 2 g and 3 g doses of nitazoxanide produced cure rates of 95% (~2~22) and 90% (n=lO) in Taenia sagtnata and Hymenolepis nana infections, respectively (ROSSIGNOL & MAISONNEUVE, 1984). Nitazoxanide was well tolerated in these clinical studies, with only minor clinical side effects such as headache and nausea being observed in 8% of the patients. The objective of the present study was to evaluate the efficacv and the safetv of nitazoxanide as a single broadspectrum antiparasitic agent in the treattnen~of mixed infections with intestinal urotozoa and helminths. The dose and duration of treatment selected for use were determined based upon results of existing animal toxicol-

ogy studies, animal pharmacology studies, animal and human pharrnacokinetic studies, and safety and efficacy data from previous clinical studies, which suggested that nitazoxanide would be safe, well tolerated by patients and effective against a broad spectrum of parasitic infections when administered at a dose of 7.5 mgikg every 12 h for 3 d in humans. Patients and Methods The protocol for the present study was approved by the ethical committee of the Mexico City General Hospital and the Mexican Health Authorities. The study was conducted at a primary school in San Pedro Toliman, Queretaro, in the Sierra Gorda, which is part of Sierra Madre Oriental of the Mexican Republic. The area is very arid, and the people are generally very poor. The principal investigator, the director of the school, school teachers, and community political leaders organized a work team to obtain faecal samples from 1864 adults and children on 3 consecutive days before initiation of the study. All faecal samples were obtained at the school. The adults or children were given articles of clothing or toys when they submitted faecal samples. Three faecal samples were obtained from each person and subjected to direct examination after staining with Lugol’s iodine, formalin-ether concentration, and an egg count using the Kato-Katz technique. Patients with cysts, oocysts or trophozoites of one protozoan and eggs or larvae of at least 2 helminths in their faeces were included in the study. Patients less than 2 years of age, those who had received antiparasitic treatment within the previous month, and female patients who were pregnant or suspected of being pregnant were excluded from the studv. A total of 340 patients, 196 adults (aged 12 years and above) and 150 children (aaed 5-l 1 vears). was included in’the study. Each paii’ent underwent a complete physical examination including determination of systolic and diastolic blood pressure and pulse rate. In addition, the weight, race, and faecal consistency were recorded. Haematology (haemoglobin, haematocrit, total and differential white blood cell count), clinical chemistry (serum glutamic oxalacetic and pyruvic transaminases, total bilirubin, blood urea nitrogen, and creatinine) and urinaIysis (protein, glucose and blood) were investigated before treatment. Each of the children received 200 mg of nitazoxanide

RAtJLROMEROCABELLO

702

(DaxonTM, Laboratorios Columbia [under licence from Romark Laboratories, USA]) administered as 10 mL of a suspension (100 mg/5 mL), twice daily in the morning and evening for 3 consecutive days. Adults received 500 mg of nitazoxanide administered as one 500 mg coated tablet, morning and evening, for 3 consecutive days. No fasting was required. The medication was administered at the school under the supervision of the principal investigator and the teachers and community leaders. The objectives and the risks associated with the study were explained by the principal investigator or members of his clinical staff to the adult patients and to the parents of the children, and written informed consent was obtained. Blood and urine samples were obtained again approximately 72 h after the last day of treatment and laboratory tests were performed on these samples as before. At the same time, the physical examination described above was repeated, and each patient was asked about the occurrence of 9 potential clinical side effects (nausea, vomiting, headache, abdominal pain, feeling faint, taste perversion, oral expulsion of parasites, epigastric pain and diarrhoea) and was asked to report any other unusual symptom which could have been caused by the drug. Each patient was asked to return to the school on days 6,7 8 (& l), 13, 14 and 15 (& l), to provide 6 post-treatment faecal samples (one for each day) for examination as described above. Once again, the adults or children were given articles of clothing or toys when they submitted each faecal sample. A total of 246 patients, 121 adults (35 males and 86 females, 12 to 78 years of age) and 125 children (53 boys and 72 girls, 5 to 11 years of age), completed the study. Fifty-two of these patients were between the ages of 12 and 19 years, and 95 were above 20 years of age; Table 2. Efficacy

of nitazoxanide

Parasite Ascaris lumbricoides Light Moderate Heavy Trichuris trikhiura Light Moderate Hymenolepis nana Light Moderate Enterobius vermiculari? Taenia saginataaab

ETAL.

any particular parasite after treatment among those who had had at least one positive examination for that particular parasite before treatment. Proportions were compared using standard x2 tests. Arithmetic means of the 3 egg counts before treatment, the 3 counts on or about day 7, and the 3 on or about day 14 were calculated for each patient. The geometric mean of these 3 values was estimated for all patients infected with a given helminth as exp [@log ,(c+l))/n]-1, where c is the egg count (eggs/g) for a particular patient. Changes in egg counts for each patient were calculated as Di=lOg, (co+l)-log,(cl+l), where co is the arithmetic mean of the 3 egg counts before treatment, c1 is the arithmetic Table 1. Efficacy of nitazoxanide of protozoan infections Parasite

for the treatment No. of cases

No. ‘curedya

164 87 10 2

133 (81%) 62 (71%) lO(lOO%) 2(100%)

Entamoeba histolyticalE. dispar Giardia duodenalis Blastocystis hominis Isospora belli a‘Cure’ rate in parentheses.

mean of the 3 counts for the patient on day 13, 14 and 15, and Di is the difference for the ith child. The differences for the adults and children were compared by analysis of variance (ANOVA). The percentage egg count reduction induced by treatment was estimated as 100 [ 1-exp(-D)], where D is the mean difference. For purposes of data analysis, each helminth infectionwas classified as light, moderate or heavy, and the ‘cure’ rates and egg reductions were analysed by degree

for the treatment

of hehninthic

infections

No. excreting;::; Before treatment treatment

‘Cure’ rate

Before treatment

Geometric mean egg count Reduction Day 14 Day 7 (%I

43 144 33

0 26 17

100% 82% 48%

1094 4756 13124

0 2 34

0 2 36

100% 99.9% 99.7%

86 9

19 4

78% 56%

798 2743

2 13

2 14

99.6% 99.5%

130 50 5 5

4 8 1 5

97% 84% 80% 100%

1095 2596 -

0 1

0 2

99.9% 99.9% -

-

-

aEgg counts not used for diagnosis of these helminthic infections. Patients with Tueniu suginata were not followed-up for the 90 d recommended in order to detect regeneration of the segments in case of treatment failure. 111 patients (45%) were infected by 3 parasites, 114 (46%) by 4, 16 (7%) by 5,4 (2%) by 6, and one patient was infected by 7 parasites. In all cases, protozoan infections were associated with helminths; 900 infections were diagnosed among the 246 patients, a mean of 3.7 infections per patient. All the patients completing the study were asymptomatic with the exception of 2 adults with diarrhoea before treatment. Ninety-four patients (73 adults and 21 children) failed to complete the study-they either failed to return to take the medication or to submit faecal samples, or both. Data from case report forms prepared by the principal investigator were entered into a computer database (Microsoft EXCEL@) and analysed. ‘Cure’ rates following treatment with nitazoxanide were estimated as the proportion of patients with 6 negative parasitological examinations for oocysts, cysts, trophozoites, eggs or larvae of

of infection. Ascaris lumbrikoides infections were classified as light when the mean pre-treatment egg count was less than 2000 eggs/g, moderate when it was between 2000 and 10000 eggs/g, and heavy when it exceeded 10000 eggs/g. Trichurik trichiura and Hymenolepis nana infections were classified as light when the mean pretreatment egg count was less than 2000 eggs/g, moderate when it was between 2000 and 5000 eggs/g, and heavy when it was greater than 5000 eggs/g. Results Treatment with nitazoxanide was generally very successful in eradicating both protozoan and helminth infections (Tables 1, 2). There was no statistically significant difference in any proportional ‘cure’ rate or egg reduction between the children and adults when the results for each group were analysed separately. ‘Cure’

NITAZOXANIDEFORINTESTINALPARASITOSES

703

rates and egg reduction were greater with light than moderate infections with helminths, and better with moderate than heavy infections. Diarrhoea reported by the 2 adults before treatment was resolved after treatment with nitazoxanide. Nitazoxanide was well tolerated by the patients; 15 (3 children and 12 adults) reported transient abdominal pain lasting less than 24 h. Haematological values obtained before and after treatment did not show any significant change. In 7 patients, there was a slightly elevated white blood cell count before and after treatment. Liver function tests were normal in all patients before and after treatment, and renal function tests were normal except in 4 cases. Three children (aged 6 to 8 vears) had an abnormallv hiah creatinine level (3.0-3.9 m&j before treatment, which increased after treatm&t-(post-treatment

values 4.1-4.6

mgiL).

In another

child. the level was normal before treatment (1.0 ma/L) and only slightly abnormal after treatment (1.6 maL): Based upon results of animal toxicology studies, these abnormalities were not considered to be drug-related. Discussion This trial confirmed that nitazoxanide administered at a dose of 7.5 mgikg every 12 h for 3 consecutive days was effective in eradicating a broad spectrum of mixed intestinal parasitic infections. This is the first antiparasitic agent reported to be effective against both protozoa and helminths. The 3 d dosing schedule followed in this study was comparable to that used with mebendazole. This regimen was brief enough to ensure good patient compliance, and shorter than treatments for intestinal amoebiasis, which last at least 7 d. In addition, nitazoxanide was well tolerated and only very minimal side effects such as epigastric or abdominal pain were recorded, with no change in the haematological and clinical chemistry values. Nitazoxanide is reported to be the first effective treatment of cryptosporidial diarrhoea in AIDS, eradicating C. paruum from the intestinal tract and leading to the resolution of the diarrhoeal syndrome in most of the parasitologically cured cases (DOUMBO et al., 1997). The activitv of nitazoxanide in curing 2 cases of ‘1. bell; infection, another coccidian protozo&, may indicate that the drug might be effective as a 3 d treat-

ment for C. parvum in immunocompetent patients. Nitazoxanide is effective as a 2 g and 3 g single dose treatment for T. sag&am and H. nana, respectively (ROSSIGNOL & MMSONNEUVE, 1984). In our studv,3 g were given over 3 d and we -obtained the same cure rate against H. nana (95%; ~180). We believe that addition% testing is warranted to determine the potential utility of this very interesting new drug. Acknowledgements The study was supported by a grant from Laboratorios Columbia SA de CV, Mexico. Laboratorios Columbia also sunnlied the nitazoxanide powder for reconstitution for children a&l the tablets for adults. References Cavier, R. & Rossignol, J. F. (1982). Etude pharmacologique de diverses associations d’anthelminthiques chez la souris. Revue de Mt!decineVe%rikaire, 123,779-783. Doumbo, O., Rossignol, J. F., Pichard, E.,Traore, H. A., Dembele, M., Diakite, M.,Traore, F. & Diallo, D. A. (1997). Nitazoxanide in the treatment of cryptosporidial diarrhea and other intestinal parasitic infections associated with acquired immunodeficiency syndrome in tropical Africa. American Journal of Tropical Medicine and Hygiene, 56, 637-639. Dubreuil, L., Houcke, X., Mouton, Y. & Rossignol, J. F. (1996). In vitro evaluation of the activities of nitazoxanide and tizoxanide against anaerobes and aerobic organisms. AntimicrobialAgents and Chemotherapy, 40,2266-2270. Em&by, J., PromTep, S. & Rossignol, J. F. (1980). Expirimentation des proprietes anthelminthiques de la nitazoxanide chez le chien, le chat et les ovins. Revue de Midecine V&&inuke, 131, 685-696. Rossignol, J. F. & Cavier, R. (1975). New derivatives of Z-benzamido-5nitrothiazoles. ChemicalAbstracts, 83,28216. Rossignol, J. F. & Maisonneuve, H. (1984). Nitazoxanide in the treatment of Taenia saginata and Hymenolepti nana. American Journal of Tropical Medicine and Hygiene, 33, 511-512. Stockis, A., Lins, R., Derobaux, X., Jeanbaptiste, B., Calderon, l? & Rossignol, J. F. (1996). Pharmacokinetics of nitazoxanide after single oral dose administration in 6 healthy volunteers. InternationalJournal of Clinical Pharmacology and Therapeutics, 34,349-35 1. Received 1997

1 May

1997; accepted for publication

27 May