Ivermectin versus benzimidazoles for treating Strongyloides stercoralis infection

What is strongyloides infection and how might ivermectin work

Strongyloides stercoralis is a parasite that lives in the gut of infected people. The infection is not serious for most people, but it can be fatal in people with immune deficiency. People become infected when they come in contact with soil or water contaminated with infectious worms. The chronic infection usually causes skin rash, vomiting, diarrhoea, and constipation, and respiratory problems, such as asthma-like illness. This disease may be treated with ivermectin or albendazole or thiabendazole. We wanted to know if ivermectin was better or worse than the other alternative therapies.

What the research says

We reviewed the evidence about the effect of ivermectin compared with albendazole and thiabendazole. After searching for relevant trials up to August 2015, we included seven randomized controlled trials, enrolling 1147 adults with chronic strongyloides infection, conducted between 1994 and 2011 in different locations (Africa, Southeast Asia, America, and Europe). Four trials assessed the effectiveness of ivermectin compared with albendazole and three trials assessed the effectiveness of ivermectin compared with thiabendazole.

Comparison ivermectin versus albendazole

Treatment with ivermectin probably cures more people than albendazole (moderate quality evidence), and may be equally or better tolerated (low quality evidence). The included trials did not report serious adverse events or death.

Comparison ivermectin versus thiabendazole

Treatment with ivermectin and thiabendazole may cure similar numbers of people with strongyloides infection (low quality evidence), but ivermectin is probably better tolerated (moderate quality evidence). The included trials did not report serious adverse events or death.

Authors' conclusions: 

Ivermectin results in more people cured than albendazole, and is at least as well tolerated. In trials of ivermectin with thiabendazole, parasitological cure is similar but there are more adverse events with thiabendazole.

Read the full abstract...
Background: 

Strongyloidiasis is a gut infection with Strongyloides stercoralis which is common world wide. Chronic infection usually causes a skin rash, vomiting, diarrhoea or constipation, and respiratory problems, and it can be fatal in people with immune deficiency. It may be treated with ivermectin or albendazole or thiabendazole.

Objectives: 

To assess the effects of ivermectin versus benzimidazoles (albendazole and thiabendazole) for treating chronic strongyloides infection.

Search strategy: 

We searched the Cochrane Infectious Diseases Group Specialized Register (24 August 2015); the Cochrane Central Register of Controlled Trials (CENTRAL), published in the Cochrane Library; MEDLINE (January 1966 to August 2015); EMBASE (January 1980 to August 2015); LILACS (August 2015); and reference lists of articles. We also searched the metaRegister of Controlled Trials (mRCT) using 'strongyloid*' as a search term, reference lists, and conference abstracts.

Selection criteria: 

Randomized controlled trials of ivermectin versus albendazole or thiabendazole for treating chronic strongyloides infection.

Data collection and analysis: 

Two review authors independently extracted data and assessed risk of bias in the included trials. We used risk ratios (RRs) with 95% confidence intervals (CIs) and fixed- or random-effects models. We pooled adverse event data if the trials were sufficiently similar in their adverse event definitions.

Main results: 

We included seven trials, enrolling 1147 participants, conducted between 1994 and 2011 in different locations (Africa, Southeast Asia, America and Europe).

In trials comparing ivermectin with albendazole, parasitological cure was higher with ivermectin (RR 1.79, 95% CI 1.55 to 2.08; 478 participants, four trials, moderate quality evidence). There were no statistically significant differences in adverse events (RR 0.80, 95% CI 0.59 to 1.09; 518 participants, four trials, low quality evidence).

In trials comparing ivermectin with thiabendazole, there was little or no difference in parasitological cure (RR 1.07, 95% CI 0.96 to 1.20; 467 participants, three trials, low quality evidence). However, adverse events were less common with ivermectin (RR 0.31, 95% CI 0.20 to 0.50; 507 participants; three trials, moderate quality evidence).

In trials comparing different dosages of ivermectin, taking a second dose of 200 μg/kg of ivermectin was not associated with higher cure in a small subgroup of participants (RR 1.02, 95% CI 0.94 to 1.11; 94 participants, two trials).

Dizziness, nausea, and disorientation were commonly reported in all drug groups. There were no reports of serious adverse events or death.

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