Sulbactam pivoxil (also called pivsulbactam) is an oral prodrug of sulbactam, a powerful beta-lactamase inhibitor used with antibiotics to fight bacterial resistance, especially by protecting antibiotics like ampicillin from breakdown by bacterial enzymes, effectively treating infections like pneumonia, UTIs, and ear infections. It works by irreversibly binding to these enzymes (beta-lactamases) that bacteria produce to destroy beta-lactam antibiotics, making the antibiotics more effective, though it's primarily known in combination with other drugs like ampicillin (Unasyn) or durlobactam for specific severe infections.