Which medication is commonly prescribed for River blindness caused by Onchocerca volvulus?

Ivermectin is commonly prescribed for River blindness, which is caused by the parasitic infection of Onchocerca volvulus. This medication works by targeting the microfilariae (the larval stage of the worm) as well as adult worms. Ivermectin acts on the nematodes by opening chloride channels and causing paralysis and death of the parasites, which helps in alleviating the symptoms and preventing further complications associated with the disease.

The effectiveness of ivermectin in treating Onchocerca volvulus is well-established, and it is often administered as a single dose once a year in endemic areas to reduce the transmission and morbidity of the disease. This approach aligns with public health initiatives aimed at controlling filarial infections.

Other medications listed do not have a role in treating River blindness. For example, 5-ASA is primarily used for inflammatory bowel diseases, fresh frozen plasma is utilized in transfusions and clotting disorders, and metronidazole is effective against certain bacterial and protozoal infections, but not for helminthic infections like those caused by Onchocerca volvulus.