Fosfomycin antibiotic drug, molecular model. This drug, marketed as Monurol, was first developed in 1978. It is used to treat urinary tract infections and bladder infections in women. After entering the bacterial cells responsible for the infection, it weakens their cell walls, causing them to split. Often the drug is used in combination with other antibiotics for increased effect. Atoms in this model are represented by coloured spheres; carbon is green, hydrogen is white, oxygen is red and phosphorous is orange.