Loracarbef, which is the first agent of the carbacephem class of beta-lactam antibiotics to be developed, provides good activity against a broad spectrum of bacteria. A single-blinded, randomized, parallel clinical trial in 10 centers in the United States compared the efficacy and safety of loracarbef with that of amoxicillin/clavulanate potassium in the treatment of acute bacterial maxillary sinusitis. A 7-10-day regimen of loracarbef (400 mg twice daily) was as effective as amoxicillin/clavulanate (500/125 mg three times a day) and resulted in somewhat fewer side effects. The results of a European trial in Sweden, Finland, and Iceland showed that loracarbef was clinically more effective than doxycycline in the treatment of acute bacterial maxillary sinusitis.