Scand J Infect Dis 34: 918–920, 2002 Giardiasis Treatment in Turkish Children with a Single Dose of Ornidazole AHMET O È ZBILGIN 1 , PELIN ERTAN 2 , KOR YERELI 1 , A. TAYLAN TAMAY 1 , O È ZGU È R KURT 1 , KENAN DEGERLI 3 , I. CU È NEYT BALCIOGLU 1 ,U È LGEN Z. OK 1 and ALI ONAG 2 From the Departments of 1 Parasitology, 2 Pediatrics and 3 Microbiology, Celal Bayar University School of Medicine, Manisa , Turkey This study was designed to compare the treatment efcacy of single dose of ornidazole with 5 d treatments of ornidazole and metronidazole in children with giardiasis. 175 children, between 2 and 15 y old, whose stool samples were found to be positive for Giardia lamblia cysts and/ or trophozoites by either saline–Lugol, formalin–ethyl acetate or trichrome staining, were enrolled in the study. Of these children, 105 were treated with a single dose of ornidazole: 35 with 30 mg/ kg, 35 with 25 mg/ kg and 35 with 20 mg/ kg; 35 were treated with 25 mg/ kg per day of ornidazole for 5 d in 2 doses and 35 children were treated with 20 mg/ kg per day metronidazole for 7 d in 3 doses. All cases were examined on the 7th, 10th and 14th days after treatment by the same methods; clinical symptoms were also evaluated. Giardia lamblia was eradicated in 34 of 35 (97%), 34 of 35 (97%) and 33 of 35 (94%) patients treated with 30, 25 and 20 mg/ kg single doses of ornidazole, respectively. Eradication was achieved in all 35 patients treated with 25 mg/ kg per day ornidazole for 5 d and in 31 of 35 (89%) patients treated with metronidazole. There was no statistically signicant difference among doses of ornidazole (p \0.05); however, all ornidazole treatment regimens were signicantly more effective than metronidazole treatment (p B0.05). No important side-effects were detected in any patients and clinical symptoms disappeared in all. Single-dose ornidazole treatment could be considered as a proper and effective alternative method for the treatment of giardiasis in children. A. O Ù zbilgin, P.K. 75 45010 Manisa , Turkey (Tel. »90 236 234 90 70 304, fax. »90 236 237 02 13, e -mail. ozbilgin@dr.com) INTRODUCTION Giardia lamblia, a agellated enteric protozoan, is a com- mon cause of endemic and epidemic diarrhoea throughout the world, as in Turkey. Infection with G. lamblia includes asymptomatic cyst passage, acute self-limited diarrhoea, and a chronic syndrome of diarrhoea with malabsorption and weight loss. Children are more liable to clinical giardia- sis than adults. Major clinical manifestations of giardiasis are malaise, nausea and anorexia, and less commonly ab- dominal pain, atulence and fever. It occasionally has a long duration or recurrences, causing malabsorption and, consequently, physical and mental disorders. All patients, with or without symptoms, should be treated medically as they could infect other people. Today, 5-nitroimidazole derivatives (metronidazole, ornidazole, tinidazole and sec- nidazole) are commonly used in giardiasis treatment and the oral route is preferred for the treatment (1–4). Metronidazole is usually the preferred drug in giardiasis treatment throughout the world. However, the side-effects of this drug and its 5 d treatment protocol are important factors affecting compliance, especially in children (5). Ac- cording to some studies, ornidazole and tinidazole are more effective than metronidazole in giardiasis treatment and they are associated with high efcacy rates in single-dose regimens (6, 7). Ornidazole (a-chloromethyl)-2-methyl-5-nitroimidazole- 1-ethanol) is structurally similar to metronidazole and tinidazole. Its oral absorption is almost complete, with bioavailability of \90% and t max ranging between 2 and 4 h. Protein binding is approximately 11–13% and its half- life values are between 11 and 14 h in individuals without liver dysfunction. Ornidazole and its metabolites are pri- marily excreted in the urine; however, the pharmacokinetics of ornidazole is not inuenced by any degree of renal dysfunction. As with metronidazole, its elimination is im- paired in patients with severe liver dysfunction. Ornidazole has similar or slightly lower minimal inhibitory concentra- tion (MIC) values than metronidazole against a variety of anaerobic bacteria and protozoa (8). These results warrant a comparative study of the conven- tional metronidazole treatment with ornidazole. This study compared the outcomes of giardiasis treatment by 5 d treatment regimens of both metronidazole and ornidazole with 3 single doses of ornidazole, which could be appropri- ate for single-dose usage owing to its longer half-life. MATERIALS AND METHODS 175 children, between 2 and 15 y old, who were admitted to Departments of Parasitology and Pediatrics with gastrointestinal complaints such as diarrhoea, weight loss, lack of appetite and fatigue, and found to be positive for G. lamblia cysts and:or trophozoites by saline – Lugol, formalin – ethyl acetate and:or trichrome staining, were enrolled in the study and fresh stool samples were taken. The parents of all enrolled children were informed about the study and their written consent was obtained. Initially, a questionnaire was developed for each treated patient, in which a record was made of the patient’s name, age, gender, address, telephone number, history of infection, coprological ex- amination report, treatment regimen, side-effects of drugs, results of the controls and comments of the supervisor. Of these children, 105 were treated with a single dose of ornida- zole (Biteral ® , Roche™): 35 with 30 mg:kg, 35 with 25 mg:kg and © 2002 Taylor & Francis. ISSN 0036-5548 DOI: 10.1080:0036554021000026962