Onchocerca volvulus infection, drugs

A study in 28 healthy subjects given levamisole 2.5 mg/kg alone or with albendazole 400 mg found that albendazole produced a modest reduction in the AUC of levamisole but no other pharmacokinetic parameters were affected. However, the AUC of albendazole sulfoxide (the active metabolite) was 75% lower when given with levamisole than historical values in subjects who had received levamisole alone. An associated study in 44 patients found that levamisole with or without albendazole was not effective against Onchocerca volvulus infections. Both treatments caused a similar number of adverse effects. The clinical relevance of these findings is unclear, but they suggest that caution is needed if both drugs are to be given for systemic worm infections. 

In humans infected with O. volvulus, ivermectin causes a rapid, marked decrease in microfi-larial counts in the skin and ocular tissues that lasts for 6—12 months. The drug has little discernible effect on adult parasites, even at doses as high as 800 ig/kg, but affects developing larvae and blocks egress of microfilariae from the uterus of adult female worms. Regular treatment with ivermectin also may act prophylactically against the development of Onchocerca infection. 

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