What is a potential side effect of using Ivermectin in susceptible patients?

Ivermectin is a widely used anthelmintic agent effective against various parasitic infections, including onchocerciasis (river blindness), lymphatic filariasis, and strongyloidiasis. A significant potential side effect associated with Ivermectin, particularly in susceptible patients, is the Mazzotti reaction.

The Mazzotti reaction occurs when Ivermectin kills microfilariae (the larval stage of filarial worms) rapidly. This can lead to an intense inflammatory response as the body reacts to the dying parasites releasing antigens. Symptoms may include fever, rash, joint pain, and lymphadenopathy. This reaction is particularly noted in individuals infected with Onchocerca volvulus, the causative agent of river blindness, where the release of antigens from the dying microfilariae triggers a strong immune response.

This phenomenon highlights the importance of careful monitoring when treating patients with Ivermectin, especially those with a high burden of microfilariae, to manage and mitigate severe reactions effectively.