Efficacy and safety of intravenous azithromycin followed by oral azithromycin for the treatment of acute pelvic inflammatory disease and perihepatitis in Japanese women

Pelvic inflammatory disease (PID) is mainly caused by ascending infection from the vaginal flora including the sexually transmitted organisms, Neisseria gonorrhoeae and Chlamydia trachomatis, and lower genital tract endogenous anaerobes, leading to serious consequences including infertility and ectopic pregnancy. To evaluate the efficacy and safety of azithromycin in the treatment of PID that requires initial intravenous therapy, we conducted a multicenter, unblinded, non-comparative phase 3 trial. Intravenous azithromycin (500 mg, once daily) for 1 or 2 days followed by oral azithromycin (250 mg once daily) to complete a total of 7 days treatment was administered to 60 Japanese women with acute PID. The clinical and bacteriological responses were assessed at the end of treatment, and on Days 15 and 29. The most commonly detected baseline causative pathogens were C. trachomatis (12 strains), Prevotella bivia (10 strains), Streptococcus agalactiae (7 strains), N. gonorrhoeae and Peptostreptococcus anaerobius (6 strains each). The clinical success rate on Day 15 was 94.1% (48/51 subjects including perihepatitis). The clinical efficacy and bacterial eradication rates against C. trachomatis and N. gonorrhoeae (including 2 quinolone-resistant strains) were both 100%. Common treatment-related adverse events were diarrhoea, injection site pain, and nausea. All adverse events were mild or moderate in severity. Azithromycin intravenous-to-oral switch therapy demonstrated excellent clinical and bacteriological effects for PID caused by various etiologic agents including quinolone-resistant strains and strains with low susceptibility to azithromycin at in vitro testing. The therapy was well tolerated in the treatment of PID in Japanese women.Registration number: NCT00871494.