[Contraceptive efficacy of bioadhesive benzalkonium chloride gel in comparison with nonoxynol-9 gel].

OBJECTIVE:To compare the contraceptive efficacy of a new spermicide, bioadhesive benzalkonium chloride (BZK) gel, with the traditional nonoxynol (NP-9) gel. METHODS:A total of 240 child-bearing age women volunteers were randomly divided into two groups: 120 using the BZK gel for contraception, and the other 120 using the NP-9 gel. Using life table method and log-rank test, we compared the pregnancy rates and discontinuation rates after follow-up for 6 months in two groups. RESULTS:No abnormal findings of cervical smears were detected before and after this clinical trial in all 240 women. The follow-up rates at 6 months were 100.0% and 99.2% in the BZK group and the NP-9 group, respectively. The 6-month gross cumulative pregnancy rates of typical use were 1.72 and 0.91 per 100 women (P > 0.05), respectively. If we excluded the 2 pregnant women (1 in each group), who did not correctly or consistently use the spermicides for every intercourse, the cumulative pregnancy rates at 6 months in perfect use would be 0.87 and 0 per 100 women (P > 0.05). And the gross cumulative discontinuation rates due to allergy or other adverse reactions at 6 months in typical use were 0 and 2.68 per 100 women (P > 0.05), respectively. CONCLUSION:The contraceptive efficacy of bioadhesive BZK gel is the same as that of the NP-9 gel, and it is more acceptable in clinical use.