Treatment strategies for nitroimidazole-refractory giardiasis: a systematic review

Bourque, Daniel L., Neumayr, Andreas, Libman, Michael, and Chen, Lin H. (2022) Treatment strategies for nitroimidazole-refractory giardiasis: a systematic review. Journal of Travel Medicine, 29 (1). taab120.

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Rationale for review: Giardiasis is one of the most common human protozoal infections worldwide. First-line therapy of giardiasis includes nitroimidazole antibiotics. However, treatment failure with nitroimidazoles is increasingly reported, with up to 45% of patients not responding to initial treatment. There is no clear consensus on the approach to the management of nitroimidazole-refractory giardiasis. This systematic review aims to summarize the literature on pharmacotherapy for nitroimidazole-refractory giardiasis.

Methods: We conducted a systematic review of the literature to determine the optimal management strategies for nitroimidazole-refractory giardiasis. We searched Pubmed/MEDLINE, Embase and Cochrane library using the following search terms ‘Giardia’ AND ‘treatment failure’ OR ‘refractory giardia’ OR ‘resistant giardia’ with date limits of 1 January 1970 to 30 June 2021. We included all reports on humans, which described clinical outcomes of individuals with treatment refractory giardiasis, including case series and case reports. A descriptive synthesis of the data was conducted with pooling of data for interventions.

Key findings: Included in this review were five prospective studies, three retrospective studies, seven case series and nine case reports. Across these reports, a wide heterogeneity of treatment regimens was employed, including retreatment with an alternative nitroimidazole, combination therapy with a nitroimidazole and another agent and monotherapy with non-nitroimidazole regimens, including quinacrine, paromomycin and nitazoxanide. Retreatment with a nitroimidazole was not an effective therapy for refractory giardiasis. However, treatment with a nitroimidazole in combination with albendazole had a cure rate of 66.9%. In the included studies, quinacrine monotherapy was administered to a total of 179 patients, with a clinical cure rate of 88.8%. Overall, quinacrine was fairly well tolerated.

Conclusions: Reports on the treatment of nitroimidazole-refractory giardiasis demonstrate a heterogeneous approach to treatment. Of these, quinacrine appeared to be highly effective, though more data on its safety are needed.

Item ID: 72348
Item Type: Article (Research - C1)
ISSN: 1708-8305
Keywords: Giardia, treatment, quinacrine, albendazole, diarrhoea, metronidazole, nitroimidazole
Copyright Information: © The Author(s) 2021. Published by Oxford University Press on behalf of International Society of Travel Medicine. All rights reserved. For permissions, please e-mail:
Date Deposited: 09 Feb 2022 14:00
FoR Codes: 32 BIOMEDICAL AND CLINICAL SCIENCES > 3202 Clinical sciences > 320203 Clinical microbiology @ 50%
32 BIOMEDICAL AND CLINICAL SCIENCES > 3202 Clinical sciences > 320209 Gastroenterology and hepatology @ 50%
SEO Codes: 20 HEALTH > 2001 Clinical health > 200105 Treatment of human diseases and conditions @ 100%
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