A dosing study of nonoxynol-9 and genital irritation

The objective of the study was to assess the symptoms and signs of genital irritation produced by different frequencies of nonoxynol-9 (N-9) use. Thirty-five women were randomized to each of 5 groups and used a vaginal suppository for 2 weeks. Group 1: N-9 once every other day; Group 2: N-9 once a day; Group 3: N-9 twice a day; Group 4: N-9 4 times a day; and Group 5: placebo 4 times a day. Study women were examined at admission, one week and 2 weeks with a colposcope for erythema and epithelial disruption, and were interviewed about vaginal itching and burning. The rates of reported symptoms for N-9 users were not significantly different from that of placebo users. The rate of epithelial disruption for women using N-9 every other day was essentially the same as that of women using placebo. The rates of epithelial disruption for women using N-9 1/day and 2/day were 2.5 times greater than that of placebo users. The rate of epithelial disruption for women using N-9 4/day was five times greater than that of placebo users. Genital irritation was located primarily on the vagina or cervix, and vulvitis was not a significant problem. Women who infrequently use N-9 products may not experience an increase in genital irritation. Women who choose to use N-9 frequently may experience an increase in epithelial disruption.