Is fosfomycin a strong antibiotic? https://www.dosepharmacy.com/fosirol-powder-3g-sachet Yes, fosfomycin is a strong antibiotic. It is a broad-spectrum antibiotic, meaning that it is effective against a wide range of bacteria. Fosfomycin is typically used to treat urinary tract infections (UTIs) and cystitis (bladder infection) in women. It is also used to treat other types of infections, such as pelvic inflammatory disease (PID) and gonorrhea.