Comparison of chloroquine, albendazole and tinidazole in the treatment of children with giardiasis

Giardia duodenalis: Biology and Pathogenesis

Giardia duodenalis captured the attention of Leeuwenhoek in 1681 while he was examining his own diarrheal stool, but, ironically, it did not really gain attention as a human pathogen until the 1960s, when outbreaks were reported. Key technological advances, including in vitro cultivation, genomic and proteomic databases, and advances in microscopic and molecular approaches, have led to an understanding that this is a eukaryotic organism with a reduced genome rather than a truly premitochondriate eukaryote. This has included the discovery of mitosomes (vestiges of mitochondria), a transport system with many of the features of the Golgi apparatus, and even evidence for a sexual or parasexual cycle. Cell biology approaches have led to a better understanding of how Giardia survives with two nuclei and how it goes through its life cycle as a noninvasive organism in the hostile environment of the lumen of the host intestine. Studies of its immunology and pathogenesis have moved past the general understanding of the importance of the antibody response in controlling infection to determining the key role of the Th17 response. This work has led to understanding of the requirement for a balanced host immune response that avoids the extremes of an excessive response with collateral damage or one that is unable to clear the organism. This understanding is especially important in view of the remarkable ranges of early manifestations, which range from asymptomatic to persistent diarrhea and weight loss, and longer-term sequelae that include growth stunting in children who had no obvious symptoms and a high frequency of postinfectious irritable bowel syndrome (IBS).

Efficacy and tolerability of quinacrine monotherapy and albendazole plus chloroquine combination therapy in nitroimidazole-refractory giardiasis: a TropNet study

BACKGROUND

Giardiasis failing nitroimidazole first-line treatment is an emerging clinical problem in returning European travelers. We present data on the efficacy and tolerability of two second-line treatment regimens.

METHODS

Prospective, open-label, multi-center study assessing the efficacy and tolerability of quinacrine monotherapy (100mg TID for 5 days) and albendazole plus chloroquine combination therapy (400mg BID plus 155mg BID for 5 days) in nitroimidazole-refractory giardiasis, defined as cases with persisting or relapsing infection despite single or repeated courses of nitroimidazole treatment. The defined endpoints were the clinical outcome, assessed by a questionnaire, at week 5 after treatment and the parasitological outcome, assessed by microscopy of 2 stool samples, ≥2-≤5 weeks after treatment.

RESULT

106 patients were included in the study. Quinacrine achieved clinical and parasitological cure in 81% (59/73) and 100% (56/56), respectively. Albendazole plus chloroquine achieved clinical and parasitological cure in 36% (12/33) and 48% (12/25), respectively. All patients (9/9) who clinically and parasitologically failed albendazole plus chloroquine treatment and opted for re-treatment with quinacrine achieved clinical cure. Mild to moderate treatment-related adverse events were reported by 45% and 30% of patients treated with quinacrine and albendazole plus chloroquine, respectively. One patient treated with quinacrine developed severe neuropsychiatric side effects. The majority of nitroimidazole-refractory Giardia infections (57%) were acquired in India.

CONCLUSION

Quinacrine was a highly effective treatment in nitroimidazole-refractory giardiasis, but patients should be cautioned on the low risk of severe neuropsychiatric adverse event. Albendazole plus chloroquine had a low cure rate in nitroimidazole-refractory giardiasis. Nitroimidazole-refractory giardiasis was primarily seen in travelers returning from India.

Giardiasis treatment: an update with a focus on refractory disease

PURPOSE OF REVIEW

Giardiasis remains a common cause of diarrhea and intestinal enteropathy globally. Here we give an overview of clinical treatment studies and discuss potential mechanisms and molecular targets for in-vitro testing of drug resistance.

RECENT FINDINGS

Giardia is a cause of disease both in diarrheal and nondiarrheal cases. The prevalence of treatment refractory giardiasis is increasing. Recent studies reveal 5-nitroimidazole refractory infection occurs in up to 50% of cases. Mechanisms of drug resistance are not known. Placebo controlled studies of drug efficacy, taking the self-limiting course of giardiasis into account, has not been reported. No randomized controlled trials of treatment of refractory infection have been performed the last 25 years. Based on the clinical studies reported, combination treatment with a 5-nitroimidazole and a benzimidazole is more effective than repeated courses of 5-nitroimidazole or monotherapies in refractory cases. Quinacrine is effective in refractory cases, but potentially severe side effects limit its use.

SUMMARY

A combination of a 5-nitroimidazole and albendazole or mebendazole, and quinacrine monotherapy, are rational choices in nitroimidazole refractory infections, but randomized controlled studies are needed. Further research into more recent clinical isolates is necessary to uncover mechanisms for the increase in metronidazole refractory giardiasis observed during the last decade.

5-Nitroimidazole refractory giardiasis is common in Matanzas, Cuba and effectively treated by secnidazole plus high-dose mebendazole or quinacrine: a prospective observational cohort study

OBJECTIVE

To evaluate the effectiveness and tolerability of secnidazole combined with high-dose mebendazole for treatment of 5-nitroimidazole-resistant giardiasis.

METHOD

Adults with microscopically verified Giardia intestinalis monoinfection attending a secondary level hospital in Matanzas City, Cuba were prospectively included in a cohort. A recently introduced treatment ladder consisting of metronidazole as first-line treatment, followed by secnidazole, tinidazole, secnidazole plus mebendazole and quinacrine as second-to fifth-line treatments, respectively, was used. Adverse events and treatment success were determined by questioning and microscopy on concentrated stool samples, respectively on days 3, 5 and 7 after the end of treatment. If G. intestinalis was detected on day 3, 5 or 7, then the infection was classified as refractory and no further microscopy was performed.

RESULTS

A total of 456 individuals were included. Metronidazole, 500 mg three times daily for 5 days, cured 248/456 (54%) patients. A single 2-g secnidazole dose as second-line treatment cured 50/208 (24%) patients. A single 2-g tinidazole dose as third-line treatment cured 43/158 (27%) patients. Three rounds of 5-nitroimidazole therapy therefore cured 341/456 (75%) patients. Secnidazole plus mebendazole (200 mg every 8 hours for 3 days) cured 100/115 (87%) of nitroimidazole refractory infections. Quinacrine cured the remaining 15 patients. All treatments were well tolerated.

CONCLUSIONS

5-Nitroimidazole refractory giardiasis was common, indicating that an alternative first-line treatment may be needed. Retreatment of metronidazole refractory giardiasis with an alternative 5-nitroimidazole was suboptimal, indicating cross-resistance. Mebendazole plus secnidazole were well tolerated and effective for the treatment of 5-nitroimidazole refractory G. intestinalis infection in this setting.

Treatment-refractory giardiasis: challenges and solutions

Giardia is the commonest parasitic diarrheal pathogen affecting humans and a frequent cause of waterborne/foodborne parasitic diseases worldwide. Prevalence of giardiasis is higher in children, living in poor, low hygiene settings in developing countries, and in travelers returning from highly endemic areas. The clinical picture of giardiasis is heterogeneous, with high variability in severity of clinical disease. It can become chronic or be followed by post-infectious sequelae. An alarming increase in cases refractory to the conventional treatment with nitroimidazoles (ie, metronidazole) has been reported in low prevalence settings, such as European Union countries, especially in patients returning from Asia. In view of its relevance, we aim in this review to recapitulate present clinical knowledge about Giardia, with a special focus on the challenge of treatment-refractory giardiasis. We propose a working definition of clinically drug-resistant giardiasis, summarize knowledge regarding resistance mechanisms, and discuss its clinical management according to research-based evidence and medical practice. Advances in development and identification of novel drugs and potential non-pharmacological alternatives are also reviewed with the overall aim to define knowledge gaps and suggest future directions for research.

Nitroimidazole-refractory giardiasis: a growing problem requiring rational solutions

BACKGROUND

Giardia intestinalis is microaerophilic diarrhoea-causing protozoan common in countries with suboptimal sanitation. Standard treatment is with nitroimidazoles, but a growing number of refractory cases is being reported. Treatment failure has become increasingly prevalent in travellers who contract giardiasis in Asia. Clinicians are increasingly falling back on second-line and less well-known drugs to treat giardiasis.

AIMS

To review nitroimidazole-refractory G. intestinalis infection, examine the current efficacy of standard therapeutic agents, consider potential resistance mechanisms which could cause treatment failure and describe the practical aspects of managing this emerging clinical problem.

SOURCES

A PubMed search was conducted using combinations of the following terms: refractory, Giardia, giardiasis, resistance and treatment. Articles on the pharmacotherapy, drug resistance mechanisms and use of alternative agents in nitroimidazole-refractory giardiasis were reviewed.

CONTENT

We review the standard drugs for giardiasis, including their efficacy in initial treatment, mode of action and documented in vitro and in vivo drug resistance. We assess the efficacy of alternative drugs in nitroimidazole-refractory disease. Existing data suggest a potential advantage of combination treatment.

IMPLICATIONS

An optimal treatment strategy for refractory giardiasis has still to be determined, so there is no standard treatment regimen for nitroimidazole-refractory giardiasis. Further work on drug resistance mechanisms and the use of drug combinations in this condition is a priority.

A novel in vitro image-based assay identifies new drug leads for giardiasis

Giardia duodenalis is an intestinal parasite that causes giardiasis, a widespread human gastrointestinal disease. Treatment of giardiasis relies on a small arsenal of compounds that can suffer from limitations including side-effects, variable treatment efficacy and parasite drug resistance. Thus new anti-Giardia drug leads are required. The search for new compounds with anti-Giardia activity currently depends on assays that can be labour-intensive, expensive and restricted to measuring activity at a single time-point. Here we describe a new in vitro assay to assess anti-Giardia activity. This image-based assay utilizes the Perkin-Elmer Operetta^® and permits automated assessment of parasite growth at multiple time points without cell-staining. Using this new approach, we assessed the "Malaria Box" compound set for anti-Giardia activity. Three compounds with sub-μM activity (IC₅₀ 0.6-0.9 μM) were identified as potential starting points for giardiasis drug discovery.

A meta-analysis of the efficacy of albendazole compared with tinidazole as treatments for Giardia infections in children

Metronidazole is frequently used against Giardia infection; however, it has been associated with significant failure rates in clearing parasites from the gut; additionally, as it should be taken for 5 to 10 days, it is associated with poor compliance, probably due to side effects. Other drugs, including tinidazole (TNZ) and albendazole (ABZ) have been included in the antigiardial armamentarium. Our aim was to assess the efficacy of ABZ compared with TNZ in Giardia infections in children. A systematic review and a meta-analysis were carried out. PubMed, Medline, EMBASE, CENTRAL, and LILACS were searched electronically until February 2015. Also relevant journals and references of studies included therein were hand-searched for randomised controlled trials (RCTs). The meta-analysis was limited to RCTs evaluating the use of ABZ compared with TNZ in children with Giardia infection. The assessed outcome was parasitological efficacy. Prediction intervals (PI) were computed to better express uncertainties in the effect estimates. Five RCTs including 403 children were included. Overall, TNZ significantly outperformed ABZ without differences between subgroups defined by ABZ dosages [relative risk, (RR) 1.61 (95% CI): (1.40-1.85); P<0.0001]. The 95% prediction interval range is 1.28-2.02. There was no significant heterogeneity (I(2)=0%; Q-test of heterogeneity P=0.4507. The number-needed-to-treat, the average number of patients who need to be treated with TNZ to gain one additional good outcome as compared with ABZ was 4, 95% CI: 3-5. Our results show that TNZ outperforms ABZ in the treatment of Giardia infections in children from developing countries.

Drug Development Against the Major Diarrhea-Causing Parasites of the Small Intestine, Cryptosporidium and Giardia

Diarrheal diseases are among the leading causes of morbidity and mortality in the world, particularly among young children. A limited number of infectious agents account for most of these illnesses, raising the hope that advances in the treatment and prevention of these infections can have global health impact. The two most important parasitic causes of diarrheal disease are Cryptosporidium and Giardia. Both parasites infect predominantly the small intestine and colonize the lumen and epithelial surface, but do not invade deeper mucosal layers. This review discusses the therapeutic challenges, current treatment options, and drug development efforts against cryptosporidiosis and giardiasis. The goals of drug development against Cryptosporidium and Giardia are different. For Cryptosporidium, only one moderately effective drug (nitazoxanide) is available, so novel classes of more effective drugs are a high priority. Furthermore, new genetic technology to identify potential drug targets and better assays for functional evaluation of these targets throughout the parasite life cycle are needed for advancing anticryptosporidial drug design. By comparison, for Giardia, several classes of drugs with good efficacy exist, but dosing regimens are suboptimal and emerging resistance begins to threaten clinical utility. Consequently, improvements in potency and dosing, and the ability to overcome existing and prevent new forms of drug resistance are priorities in antigiardial drug development. Current work on new drugs against both infections has revealed promising strategies and new drug leads. However, the primary challenge for further drug development is the underlying economics, as both parasitic infections are considered Neglected Diseases with low funding priority and limited commercial interest. If a new urgency in medical progress against these infections can be raised at national funding agencies or philanthropic organizations, meaningful and timely progress is possible in treating and possibly preventing cryptosporidiosis and giardiasis.

Management of chronic Giardia infection

Advances in our understanding of chronic giardiasis (CG) may improve our care of patients in this stage of the disease. This review proposes a new concept of CG and highlights the recent advances in our understanding and management of this condition. According to this review, management requires, initially, an accurate diagnosis, which may exclude several conditions that can mimic CG. Optimal treatment requires a tailored approach which includes the recognition of the known modifiable causes of this health condition, assessment of symptoms and potential complications, their treatment utilizing, if necessary, a multidisciplinary team, and an ongoing monitoring for the effect of therapy - weighing the efficacy of individual drugs - all of these together may lead to a successful treatment of CG.

Efficacy of 5-nitroimidazoles for the treatment of giardiasis: a systematic review of randomized controlled trials

Background

Giardiasis is one of the most common causes of diarrheal disease worldwide and 5-nitroimidazoles (5-NI) are the most commonly prescribed drugs for the treatment of giardiasis. We evaluated the efficacy of 5-nitroimidazoles (5-NI) in the treatment of giardiasis in a systematic review of randomized controlled trials (RCTs).

Methodology/Principal Findings

We conducted a comprehensive literature search in PubMed-Medline, Scopus, Web of Science and Cochrane Library for RCTs evaluating the efficacy of 5-NI vs. control (placebo or active treatment) on parasitological cure in patients with parasitologically-demonstrated giardiasis. The search was performed in May 2013 with no language restriction by two authors independently. The efficacy outcome was parasitological cure, and harmful outcomes were abdominal pain, bitter or metallic taste, and headache. We included 30 RCTs (n = 3,930). There was a significant and slightly higher response rate with 5-NI in giardiasis treatment (RR 1.06, 95%CI 1.02–1.11, p = 0.005). There was high heterogeneity among studies (I² = 72%). The response rates for metronidazole, tinidazole and secnidazole were similar (RR 1.05, 95%CI 1.01–1.09, p = 0.01; RR 1.32 95%CI 1.10–1.59, p = 0.003; and RR 1.18 95%CI 0.93–1.449, p = 0.18, respectively). On subgroup analyses, the response rates did not vary substantially and high heterogeneity persisted (I² = 57%–80%). Harmful outcomes were uncommon, and 5-NIs were associated with lower risk of abdominal pain, and higher risk of both bitter or metallic taste and headache.

Conclusions

Studies investigating the efficacy of 5-NI in giardiasis treatment are highly heterogeneous. 5-NIs have a slightly better efficacy and worse profile for mild harmful outcomes in the treatment of giardiasis in comparison to controls. Larger high quality RCTs are needed to further assess efficacy and safety profiles of 5-NI.

Giardiasis is a major diarrheal disease with worldwide distribution. 5-nitroimidazoles, which include metronidazole and tinidazole, are the most commonly used drugs in the treatment of giardiasis. In recent years, many other drugs with variable efficacies and adverse effects have been proposed for the treatment of giardiasis. No systematic review has evaluated efficacy of 5-nitroimidazoles as a group in comparison to the other antigiardial drugs. In this context, we performed a systematic review of the literature to identify randomized controlled trials comparing the efficacies of 5-nitroimidazoles with a control drug with the aim of assessing effectiveness of 5-nitroimidazoles in the treatment of giardiasis. Four research databases were searched; 30 trials with 3,930 subjects met our inclusion criteria. Results show that there was a high variation of study outcomes between included studies. 5-nitroimidazoles were associated with higher giardiasis cure rates than controls; also, 5-nitroimidazoles are associated with lower risk of abdominal pain, and higher risks of bitter or metallic taste and headache than controls.

Treatment of giardiasis: current status and future directions

Giardiasis is a common yet neglected cause of diarrheal illness worldwide. Antimicrobial therapy is usually but not always effective and drug resistance has become an increasing concern. Several promising drug candidates have been recently identified that can overcome antibiotic resistance in Giardia. These include derivatives of 5-nitroimidazoles and benzimidazoles, as well as hybrid compounds created from combinations of different antigiardial drugs. High-throughput screening of large compound libraries has been a productive strategy for identifying antigiardial activity in drugs already approved for other indications, e.g. auranofin. This article reviews the current treatment of giardiasis, mechanisms of resistance, advances in drug and vaccine development, and directions for further research on this significant human pathogen.

Tinidazole: from protozoa to Helicobacter pylori – the past, present and future of a nitroimidazole with peculiarities

Tinidazole (Fasigyn, Pfizer Ltd), like metronidazole - to which it is structurally related - was initially introduced for treating protozoal infections. However, both of these nitroimidazole compounds are active against most clinically important obligate anaerobes. In the last few years, the discovery of Heliobacter pylori and of its susceptibility to nitroimidazoles focused new attention on these drugs. Tinidazole, as a part of this class of drugs, shares the characteristics and indications of other nitroimidazoles. However, it has a number of desirable features that could potentially make it very successful: a better pharmacokinetic and pharmacodynamic profile, a better safety and tolerability spectrum, and a preserved activity against some bacteria that are resistant to metronidazole.

Hospitalization of Cuban children for giardiasis: a retrospective study in a paediatric hospital in Havana

The medical records of the 185 children who, in 2007, were admitted to the Academic Paediatric Hospital 'Centro Habana', in the Cuban capital of Havana, because of giardiasis were analysed retrospectively. A standardized form was used to collect data on the socio-demographic characteristics, clinical features, laboratory diagnosis, treatment and length of stay of each child. Information on the 15 children who had incomplete medical records was excluded from the data analysis. Of the remaining 170 children, 85 (50·0%) were aged 1-4 years, 97 (57·1%) were male, and 106 (62·4%), 92 (54·1%) and 69 (40·6%) had presented with diarrhoea, vomiting, and/or abdominal pain, respectively. Most (91·2%) of the cases had been diagnosed by the microscopical examination of a duodenal aspirate, and the drugs that had been most used frequently were quinacrine and tinidazole, which had been given to 72 (42·4%) and 62 (36·5%) of the cases, respectively. The mean length of hospital stay was 4·9 days. Such information on the clinical characteristics of giardiasis among children living in an endemic area may be valuable to paediatricians and public-health officials who wish to screen for the disease.

The treatment of giardiasis in children: single-dose tinidazole compared with 3 days of nitazoxanide

Giardia lamblia is among the commonest intestinal protozoa world-wide and may cause significant morbidity, especially in children. Although 5-nitroimidazole compounds have formed the mainstay of giardiasis treatment for several years, the increasing number of reports of refractory cases given these and other antigiardial agents has raised concern and led to a search for other compounds. The aim of the present study was to compare the efficacy and safety, in the treatment of children infected with G. lamblia, of nitazoxanide, given at a dose of 7.5 mg/kg twice a day for 3 days, with those of tinidazole, given as a single dose of 50 mg/kg. Overall, 166 children, each proven to be infected with G. lamblia by the microscopical examination of a faecal sample, were included in the open and randomized trial, each being allocated to receive nitazoxanide or tinidazole. The parents of each treated child were asked to collect two faecal samples from the child between 5 and 10 days after the completion of treatment, for the parasitological follow-up. Only if no G. lamblia were found in both post-treatment samples from a child was that child considered cured. Among the 137 children who completed the study (74 given nitazoxanide and 63 given tinidazole), the frequency of parasitological cure following a single dose of tinidazole was significantly higher than that following six doses of nitazoxanide (90.5% v. 78.4%; P<0.05). Both treatment schedules were well accepted and well tolerated, with only mild, transient and self-limited side-effects reported. The commonest symptom on enrolment, diarrhoea, generally cleared 2-6 days after the initiation of treatment. Although apparently less efficacious than tinidazole, nitazoxanide remains a good candidate for the treatment of children with G. lamblia infection.

Giardiasis: a pharmacotherapy review

Giardia lamblia, the cause of human giardiasis, is among the most common intestinal protozoa worldwide. Human infection may range from asymptomatic shedding of giardial cysts to symptomatic giardiasis, being responsible for abdominal cramps, nausea, acute or chronic diarrhoea, with malabsorption and failure of children to thrive. At present, treatment options include the nitroimidazoles derivatives; especially metronidazole, which has been the mainstay of treatment for decades and is still widely used. The increasing number of reports of refractory cases with this group of drugs and other antigiardial agents, has raised concern and led to a search for other compounds, some of which have arisen due to the introduction of drugs initially addressed to other diseases. The present article examines some of the most important points of antigiardial pharmacotherapy available at present and the future prospects of development of new agents.

A randomized, controlled, open-label trial of a single day of mebendazole versus a single dose of tinidazole in the treatment of giardiasis in children

BACKGROUND

Giardia duodenalis is the most commonly detected parasite in the intestinal tract of humans and 5-nitroimidazole compounds, quinacrine and furazolidone have been used against giardiasis. However, cases refractory to treatment with these drugs are becoming more common worldwide.

OBJECTIVE

To compare the efficacy and safety of mebendazole versus tinidazole in the treatment of giardiasis.

RESEARCH DESIGN AND METHODS

122 children (aged 5 to 15 years) of both sexes with confirmed Giardia duodenalis cysts or trophozoites in their stool samples were randomly separated into two groups of 61 individuals. Each group received either mebendazole 200 mg three times for 1 day or tinidazole 50 mg/kg in a single dose. The evaluation of the efficacy was based on parasitological response. Parents or legal guardians of each child were asked to provide three fecal samples on days 3, 5, and 7 after treatment completion. A child was considered to be cured if no Giardia trophozoites or cysts were found in any of the three post-treatment fecal specimens evaluated by direct wet mounts and/or after Ritchie concentration techniques.

RESULTS

The frequency of cure was higher for tinidazole (81.97%) than for mebendazole (63.93%); the difference was statistically significant (p < 0.05). Transient abdominal pain was more common in children treated with mebendazole (p < 0.05), whereas loss of appetite, bitter taste, headache, vomiting, and nausea were more common in the tinidazole-treated group (p < 0.05).

CONCLUSIONS

Three doses of mebendazole, in a single day, are inferior to a single dose tinidazole in the treatment of giardiasis.

Randomized clinical study of five days apostrophe therapy with mebendazole compared to quinacrine in the treatment of symptomatic giardiasis in children

AIM: To compare the efficacy and safety of five days apostrophe therapy of mebendazole (MBZ) versus quinacrine (QC) on human giardiasis in children.

METHODS: A clinical trial was carried out in paediatric patients (aged 5-15 years) with confirmed symptomatic G. duodenalis mono-infection. Patients were randomly assigned to receive either MBZ [200 mg taken three times per day (TID) (n = 61)] or QC [2 mg/kg bodyweight tid (n = 61)], both for five days. Follow-up faecal samples were obtained at 3, 5 and 7 d after the end of the treatment.

RESULTS: Although the frequency of cure was higher for QC (83.6%) than for MBZ (78.7%), the difference was not statistically significant (P > 0.05). Adverse events were reported more in the QC group (P < 0.05), all of them transient and self-limiting.

CONCLUSION: Despite final cure rates ocurring lower than expected, the overall results of this study reconfirmed the efficacy of MBZ in giardiasis and also indicate that, although comparable to QC, at least in this setting the 5 d course of MBZ did not appear to improve the cure rates in this intestinal parasitic infection.

Tinidazole

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Albendazole versus metronidazole treatment of adult giardiasis: An open randomized clinical study

AIM: To investigate the efficacy and tolerability of albendazole and metranidazole treatment in giardiasis.

METHODS: The open comparative randomized trial was carried out prospectively from December 1999 to July 2001 in Duzce City of Turkey. The diagnosis was based on the presence of signs and symptoms compatible with giardiasis including a positive stool examination of giardia cysts or trophozoite. Metranidazole group consisted of 29 patients and was given metranidazole 500 mg, three times a day for 5 d and albendazole group was consisted of 28 patients and was given albendazole 400 mg/d for 5 d.

RESULTS: There were no significant differences in demographical and therapeutical effects and patient’s compliance between both groups. But side effects were seen more in metranidazole group than in albendazole group.

CONCLUSION: Albendazole is as effective as metranidazole in adults’ giardiasis. Albendazole has less side effect potentials than metranidazole in the treatment of giardiasis.

A randomized trial comparing mebendazole and secnidazole for the treatment of giardiasis

To compare the efficacy of the two drugs in the treatment of giardiasis, 146 children (aged 5-15 years) with confirmed Giardia lamblia infection were randomly allotted to treatment with mebendazole (200 mg three times daily for 3 days) or secnidazole (30 mg/kg, in a single dose). Parasitological response to treatment was evaluated in each child by the microscopical examination of faecal samples collected 3, 5 and 7 days after he or she had completed treatment. Although the frequency of cure was higher for secnidazole (79.4%) than for mebendazole (78.1%), the difference was not statistically significant (P > 0.05). Both treatment regimens were well tolerated, with only mild, transient and self-limiting side-effects reported. Mebendazole may be preferable to secnidazole in the treatment of giardiasis cases who have an history of intolerance to 5-nitromidazoles, and where infections with Giardia and soil-transmitted helminths frequently co-occur.