Wiesenfeld HC, Meyn LA, Darville T, et al. A randomized controlled trial of ceftriaxone and doxycycline, with or without metronidazole, for the treatment of acute pelvic inflammatory disease. Clin Infect Dis. February 13, 2020. doi:10.1093/cid/ciaa101.
Pelvic inflammatory disease remains prevalent among young women and is commonly diagnosed in emergency departments and sexually transmitted disease (STD) clinics. This tubal infection is associated with significant reproductive sequelae, including tubal factor infertility, ectopic pregnancy, and chronic pelvic pain. In addition, these women remain at risk for recurrent PID.
Bacterial vaginosis is present in more than half of women with PID. Not surprisingly, anaerobic microorganisms are more commonly isolated from the upper genital tract of patients with acute PID than either Neisseria gonorrhoeae or Chlamydia trachomatis, yet recommended antimicrobial regimens do not necessarily include antibiotics with an excellent antianaerobic spectrum.
Details of the study
In a randomized, double-blind, placebo-controlled trial, Wiesenfeld and colleagues enrolled women from hospital emergency departments or an STD clinic with symptoms of lower abdominal or pelvic pain associated with pelvic organ tenderness. The 233 study participants were randomly assigned to 2 treatment arms: ceftriaxone, doxycycline, and placebo (n = 117) or ceftriaxone, doxycycline, and metronidazole (n = 116).
Findings. Women treated with metronidazole were less likely to have pelvic organ tenderness a month after enrollment compared with the placebo group (9% vs 20%, respectively). Although the clinical cure rates at 30 days were statistically similar in both arms of the study, those receiving metronidazole had a 97% clinical cure rate while those not treated with metronidazole had a 90% clinical cure rate
(P = .38).
Moreover, the concurrent disorders of bacterial vaginosis and trichomonas vaginitis were more effectively treated in the metronidazole group, and fewer women had positive follow-up endometrial cultures for anaerobic bacteria compared with the placebo group (8% vs 21%, respectively).
The anticipated gastrointestinal adverse effects of a combination doxycycline-and-metronidazole regimen was a significant concern; however, combination therapy was no more likely to cause gastrointestinal adverse effects than doxycycline alone.
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