What do systematic reviews say?

Doxycycline vs tetracycline

It is very uncertain whether doxycycline changes treatment failure compared with tetracycline (very low certainty).

• Antibiotics for treating scrub typhus 2018 · Cochrane Headline outcomes only
  RR 6.85 [0.38, 124.38]
  1 study · 116 participants
  Very low

Doxycycline+Rifampicin vs Doxycycline+Streptomycin

Doxycycline+Rifampicin probably leads to higher total treatment failure compared with doxycycline+Streptomycin (moderate certainty).

• Antibiotics for treating human brucellosis 2012 · Cochrane Headline outcomes only
  RR 1.91 [1.07, 3.42]
  7 studies · 567 participants
  Moderate

Doxycycline+Streptomycin vs Doxycycline+Gentamycin

Doxycycline+Streptomycin showed no clear difference in total treatment failure compared with doxycycline+Gentamycin (low certainty).

• Antibiotics for treating human brucellosis 2012 · Cochrane Headline outcomes only
  OR 1.85 [0.84, 4.08]
  2 studies · 345 participants
  Low

Doxycycline+Rifampicin vs Quinolones+Rifampicin

Doxycycline+Rifampicin showed no clear difference in total treatment failure compared with quinolones+Rifampicin (moderate certainty).

• Antibiotics for treating human brucellosis 2012 · Cochrane Headline outcomes only
  OR 0.94 [0.45, 1.98]
  3 studies · 181 participants
  Moderate

Rifampicin vs doxycycline

• Antibiotics for treating scrub typhus 2018 · Cochrane Headline outcomes only
  no estimate extracted
  1 study · 78 participants
  Very low

Macrolides vs doxycycline

It is very uncertain whether macrolides changes treatment failure compared with doxycycline (very low certainty).

• Antibiotics for treating scrub typhus 2018 · Cochrane Headline outcomes only
  RR 2.71 [0.12, 63.84]
  3 studies · 242 participants
  Very low