Providers share views on N-9 as contraceptive
Still a viable option’
Contraceptive Technology Update readers have not recommended nonoxynol-9 (N-9) spermicides for HIV protection, in accordance with the Centers for Disease Control’s 1998 Guidelines for Treatment of Sexually Transmitted Diseases.1 However, they have provided women with N-9 spermicides for contraception.
Now there’s new information. The Geneva-based Joint United Nations Program on HIV/ AIDS (UNAIDS) sponsored an international trial of an N-9 gel, marketed in the United States as Advantage-S by Columbia Laboratories of Miami. The study was conducted as a triple-blind randomized multicenter trial among female sex workers. Researchers tested the effectiveness of a gel containing 52.5 mg of N-9 compared with an inactive placebo gel.
Results from the study, presented at the recent XIII International AIDS Conference in Durban, South Africa, show that women who were randomized to use the N-9 gel became infected with HIV at about a 50% higher rate than women who used the placebo gel.2 In addition, the more frequently women used only N-9 gel without a condom to protect themselves, the more their risk increased for becoming infected.
How should the results of the UNAIDS trial affect your practice?
"Our position should be, for low-risk couples in the United States, the use of N-9 is still a viable option for contraception," says David Archer, MD, professor of obstetrics and gynecology director of the Clinical Research Center at the Eastern Virginia Medical School in Norfolk and member of the CTU editorial advisory board.
Women in the UNAIDS trial were commercial sex workers who were having intercourse at a higher rate than the U.S. average, notes Archer. He does not disagree, however, with the conclusion that N-9 does not prevent HIV heterosexual transmission.
"The scientific community must continue to find an effective alternative," Archer says.
The N-9 news should not affect its use as a spermicide by average couples, says CTU board member Allan Rosenfield, MD, dean of the Mailman School of Public Health, DeLamar Professor of Public Health, and professor of obstetrics/gynecology at Columbia University in New York City.
The primary data in the UNAIDS study regarding mucosal reaction relates to multiple uses among female sex workers, he states. One study from Latin America, however, has found some mucosal changes in women with more occasional use, Rosenfield notes.3 That study needs to be repeated by others, but all the other data regarding the safe use of N-9 as a spermicide should be reassuring to women who use to use N-9 with a diaphragm or as a primary/secondary method of contraception, he says.
Results do not come as a surprise’
Michael Rosenberg, MD, MPH, says, "My understanding of the work presented in Durban is that it involved women with a high number of sexual contacts. Since N-9 is a detergent, and there is sufficient safety data from previous work to suggest that it may enhance risk in such situations, these results do not come as a surprise." Rosenberg is clinical professor of obstetrics and gynecology at the school of medicine and adjunct professor of epidemiology at the school of public health at the University of North Carolina at Chapel Hill.
He says he doesn’t believe this study provides a definitive answer for all contraceptive users. "I am wary that that we may be painting N-9 with a single broad brush stroke, when the situation is actually not so simple," says Rosenberg, who also is a CTU board member and president of Health Decisions, a private research firm in Chapel Hill, NC, specializing in reproductive health.
The vast majority of N-9 spermicide users may represent a different population, Rosenberg points out. If the product is not used very often, it can offer a protective effect, as it appears to do against chlamydia and gonorrhea,4 but in more intensive use, it could increase risk, he says.
"This makes methodological sense as well, since intermittent use [average frequency of intercourse is about two times per week in the United States] allows the vaginal epithelium to recover, but constant exposure to N-9 may not," concludes Rosenberg.
Frequent use of spermicides can cause vulvovaginal epithelial disruption, which theoretically could increase susceptibility to HIV, according to Contraceptive Technology.5 Therefore, advise caution about frequent use when HIV exposure is a concern, Contraceptive Technology recommends.
References
1. Centers for Disease Control and Prevention. 1998 Guidelines for treatment of sexually transmitted diseases. MMWR 1998; 47(No. RR-1):5.
2. Van Damme, L. Advances in topical microbicides. Presented at the XIII International AIDS Conference. Durban, South Africa; July 12, 2000.
3. Amaral E, Faundes A, Zaneveld L, et al. Study of the vaginal tolerance to Acidform, an acid-buffering, bioadhesive gel. Contraception 1999; 60:361-366.
4. Louv WC, Austin H, Alexander WJ, et al. A clinical trial of nonoxynol-9 for preventing gonococcal and chlamydial infections. J Infect Dis 1988; 158:518-523.
5. Hatcher RA, Trussell J, Stewart F, et al. Contraceptive Technology. 17th ed. New York City: Ardent Media; 1998.
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