<qa>  How long will a blood sample of doxycycline be obtained?In the doxycycline group, serial blood samples 5 mL for determination of doxycycline concentrations will be obtained before and at 0, 0.5, 1, 2, 4, 12, 24, and 48 hours following the 1-hr infusion of a single IV dose. Once daily dosing of doxycycline will resume immediately following the 48-hour blood sample and will continue until day 28. Additional levels will be obtained pre-dose, and 1, 2, and 3 hours after doses administered on days 14 and 28. A sample of blood will be obtained at baseline, and at days 28 for inflammatory marker analyses. 