2 Apr 2019 prophylactic antibiotic may be given 3 to 4 hours after the initial dose . (III-C) antibiotics (e .g ., doxycycline) should be given . (II-3B). 14 . .. Classen DC, Evans RS, Pestotnik SL, Horn SD, Menlove RL, Burke JP. The timing propeciat.com propecia online store