Atovaquone, sold under the brand name Mepron, is an antimicrobial medication for the prevention and treatment of Pneumocystis jirovecii pneumonia (PCP). Atovaquone is a chemical compound that belongs to the class of naphthoquinones. Atovaquone is a hydroxy-1,4-naphthoquinone, an analog of both ubiquinone and lawsone, with antipneumocystic activity.