Common side effects include nausea, vomiting, headache, and trouble sleeping.[3] Other side effects may include QT prolongation, psychosis, and low white blood cells.[4] It is unclear if use during pregnancy or breast feeding is safe.[4] Fexinidazole is in the antiparasitic and the nitroimidazole family of medications.[3] It is believed to work by turning on certain enzymes within the parasites that result in their death.[3]