Intravenous minocycline versus oral doxycycline for the treatment of noncomplicated scrub typhus.

Background: Scrub typhus is an acute febrile disease for which synthetic tetracycline antibiotics are efficacious. However, no clinical studies have compared oral doxycycline with intravenous minocycline for treatment of scrub typhus.

Methods: We conducted a retrospective analysis in patients diagnosed with noncomplicated scrub typhus by serologic or molecular methods from August 2001 to July 2007. We compared the efficacy of intravenous minocycline with oral doxycycline for treatment of noncomplicated scrub typhus in these patients.

Results: Forty seven cases receiving tetracycline antibiotics for the treatment of noncomplicated scrub typhus were included. There was no statistically significant difference for the response rate between the 25 cases receiving intravenous minocycline (96%) and the 22 cases receiving oral doxycycline (91%) (p=0.909). Kaplan-Meier curve with a long-rank test for the time to defervescence showed no statistically significant difference between minocycline therapy (mean 30 hours; range 4-124 hours) and doxycycline therapy (mean 32.4 hours; range 4-144 hours) (p=0.860). After multivariate Cox regression models, the time to defervescence was only affected by Acute Physiology and Chronic Health Evaluation II score (hazard ratio 0.868; p=0.016). Nearly all patients (93.6%) became afebrile within 72 hours after use of tetracycline antibiotics. Prolonged hospitalization (> 7 days) was correlated with the timing to start tetracycline antibiotics after admission.

Conclusion: Both antibiotics have similar efficacy for the treatment of noncomplicated scrub typhus. Nearly all cases responding to both antibiotics became afebrile within 3 days.