For hospitalized patients, the following two parenteral regimens have given nearly identical results in a multicenter randomized trial: 1. Doxycycline (100 mg twice daily, given IV or PO) plus cefotetan ( g IV every 12 h) or cefoxitin ( g IV every 6 h). Administration of these drugs should be continued by the IV route for at least 48 h after the patient's condition improves and then followed with oral doxycycline (100 mg twice daily) to complete 14 days of therapy. 2. Clindamycin (900 mg IV every 8 h) plus gentamicin ( mg/kg IV or IM, followed by mg/kg every 8 h) in patients.