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Efficacy of Oral Ivermectin in Treating Patients With Scabies
abstract
This abstract is available on the publisher's site.
Access this abstract nowAs Sarcoptes scabiei is becoming less sensitive to permethrin, clinicians have started to prescribe oral ivermectin (OI) as a first-line treatment. Guidelines suggest OI 200 µg kg-1 as two doses, 1 week apart. However, the black box of the ivermectin registered in Italy recommends a single dose. To compare these two regimens, we collected 71 cases of scabies and treated them according to this protocol [single-dose group (SDG)]. This population was compared to 68 patients who received two doses 1 week apart [double-dose group (DDG)]. Clearance of the disease was achieved in 98% of DDG patients. In the SDG, treatment was successful in only 58% of patients. This study confirms that the absence of a second intake of OI is one of the main predictors of treatment failure (P < 0.001), which may also increase the likelihood of emerging resistance in S. scabiei.
Additional Info
Oral ivermectin to treat scabies: a comparison of two different regimens
Clin Exp Dermatol 2023 Mar 01;48(3)232-234, R Balestri, M Magnano, SD Infusino, CR Girardelli, T Ioris, G RechFrom MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
Scabies is recognized as a neglected tropical disease (NTD) by the World Health Organisation (WHO), and it reaches epidemic levels of infestation in several resource-limited settings. In such environments, ivermectin is given to whole communities (so-called mass drug administration [MDA]), regardless of whether individuals have signs or symptoms of scabies. A review of MDA efficacy includes seven studies, in which single-dose ivermectin was used, and reports a relative reduction in scabies prevalence in the communities treated, ranging from 31% to 99.9%.1 With the convenience of single dosing being a major driver, evidence which disputes this as a reasonable strategy is important to review. This brief observational research report describes how, following a single dose of ivermectin for scabies, as approved by the Italian licensing system, 42% of 71 scabies cases treated had persistent infestation when reviewed a month after therapy.2 This compared poorly with a previously published series of patients from the same group, wherein just 2% of a group of 68 failed therapy after receiving double-dose oral ivermectin a week apart. Those in the double-dose group had all previously failed to clear on topical anti-scabetic treatment. The ivermectin dose and additional management approaches were identical with the provision of written advice, including environment management recommendations. Single-dose ivermectin treatment is approved in a number of countries, with the advantage of being convenient. Single dose is directly at odds with the 2017 European Guideline on Management of Scabies, which advocates two doses a week apart, recognizing that ivermectin is not ovicidal, and so the second dose is required to deal with mites hatching from the eggs persisting after the first treatment.3 The concern expressed by the authors is that extensive use of single-dose ivermectin may lead to widespread treatment failure and the emergence of resistance. This short report suggests that further work is needed to address the efficacy of single-dose ivermectin for scabies in a robust and randomized way and to clarify whether the recommendations will vary in the intervention setting. Perhaps, it may continue to be expedient in community outbreaks where MDA is to be administered. Prioritizing this research gap should be considered by the International Alliance for the Control of Scabies.4
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