Drugs for treating urinary schistosomiasis.

BACKGROUND: Urinary schistosomiasis causes long-term ill-health. This review examines the various treatment options and newer drugs.
OBJECTIVES: To evaluate antischistosomal drugs, used alone or in combination, for treating urinary schistosomiasis. SEARCH STRATEGY: In August 2007, we searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (The Cochrane Library 2007, Issue 3), MEDLINE, EMBASE, LILACS, mRCT, and reference lists of articles. We also contacted experts in schistosomiasis research. SELECTION CRITERIA: Randomized and quasi-randomized controlled trials of praziquantel, metrifonate, artemisinin derivatives, or albendazole, alone or in combination, versus placebo, different doses, or other antischistosomal drugs for treating urinary schistosomiasis. DATA COLLECTION AND ANALYSIS: One author extracted data, and assessed eligibility and methodological quality, which were cross-checked by a second person. Dichotomous outcomes were combined using risk ratio (RR), and continuous data were combined using weighted mean difference (WMD); both presented with 95% confidence intervals (CI). MAIN
RESULTS: Twenty-four trials (6315 participants) met the inclusion criteria. Compared with placebo, participants receiving metrifonate had fewer parasitological failures at follow up at one to three months (1 trial) and three to 12 months (3 trials). Egg reduction rate was over 90%, and no adverse events were reported (1 trial). One metrifonate dose was inferior to three doses given fortnightly (both used 10 mg/kg). Praziquantel (standard single 40 mg/kg oral dose) was more effective than placebo at reducing parasitological failure at one to three months' follow up and three to 12 months. Egg reduction rates were improved with praziquantel (over 95% versus 5.3% to 64% with placebo). Mild to moderate adverse events were recorded in two trials. A comparison of metrifonate (10 mg/kg x 3, once every 4 months for one year) with praziquantel (standard dose) showed little difference in parasitological failure. For praziquantel, there was no significant difference in effect between 20 mg/kg x 2, 30 mg/kg x 1, and 20 mg/kg x 1, and the standard dose for all outcomes. One small trial of artesunate showed no obvious benefit compared with placebo, and the artesunate-praziquantel combination was similar to praziquantel alone. AUTHORS'
CONCLUSIONS: Praziquantel and metrifonate are effective treatments for urinary schistosomiasis and have few adverse events. Metrifonate requires multiple administrations and is therefore operationally less convenient in community-based control programmes. Evidence on the artemisinin derivatives is currently inconclusive, and further research is warranted on combination therapies. We suggest metrifonate be reconsidered for the WHO Model List of Essential Medicines.