Effectiveness of an optimized benzalkonium chloride gel as vaginal contraceptive: a randomized controlled trial among Chinese women

This study was conducted to evaluate the efficacy, safety and acceptability of a newly developed benzalkonium chloride (BZK) contraceptive gel which was compared to nonoxynol-9 (N-9) gel.

A Phase II, multicenter, randomized, controlled study at three Chinese centers was conducted to compare 120 women who used BZK gel with 120 women who used N-9 gel for 6 months. Contraceptive efficacy was assessed by pregnancy rate, and safety was evaluated by adverse events report, gynecologic examination, Papanicolaou smears, leukorrhea test, and blood and urine tests. The acceptability was assessed through follow-up visit forms and a questionnaire at the 6-month visit.

Net cumulative rates in the BZK group at 6 months were as follows: follow-up 100%, terminations 5.1%, pregnancy 1.7%, medical reasons 0% and fear of failure 3.4%. At 6 months, the rates in the N-9 group were as follows: follow-up 99.2%, terminations 9.4%, pregnancy 0.9%, medical reasons 2.5%, fear of failure 3.4% and other personal reasons 2.6%. No significant difference in pregnancy rate and termination rate between the two groups was found (p>.05). Seven cases in the BZK group (5.8%) complained about leukorrhagia and vaginal irritation symptoms (itching and burning) at 6 months, while 16 cases in the N-9 group (13.3%) had similar complaints (p<.05). This significant difference continued to exist until the 6-month visit. The general satisfaction rate for BZK gel use (72.8%) is significantly higher than that for N-9 gel (42.5%).

The optimized BZK gel is comparable to N-9 gel in terms of contraceptive efficacy and safety, and may be more acceptable to Chinese users.