Nonoxynol-9 not protective against STDs
New research suggests that nonoxynol-9 (N-9), the most commonly used spermicide worldwide, does not protect against urogenital gonorrhea and chlamydial infection.1
Researchers have hoped that N-9, a nonionic detergent that has been used as a spermicide for 50 years, would prove effective against a variety of sexually transmitted diseases (STDs) because it has been successful against many bacteria, including gonorrhea and chlamydia, in laboratory settings.
Based on the results of the new study and research spanning more than a decade of N-9 as a vaginal microbicide, it is time to move on in developing new female-controlled forms of protection against STDs, asserts Barbra Richardson, PhD, research assistant professor of biostatistics at the University of Washington in Seattle. Richardson is the author of a companion editorial to the published research.2
The need for effective microbicides is vital, says Richardson. Most new HIV-1 infections worldwide are contracted through heterosexual intercourse; while the male condom provides protection from acquisition of STDs, use of a male condom requires agreement by both sexual partners, she points out.
"Despite improvements in the availability and distribution of male condoms and large-scale educational campaigns, HIV-1 and other STDs continue to spread at high rates in many parts of the developing world," says Richardson. "All of these facts indicate a strong need for the development of inexpensive, effective, female-controlled methods for prevention of STDs — such as vaginal microbicides."
Examine the data
The just-published study, conducted by Research Triangle Park, NC-based Family Health Interna-tional researchers and colleagues in Cameroon, found that nonoxynol-9, when used with condoms, did not protect women from the bacteria that cause gonorrhea and chlamydial infection any better than condoms used alone.
The randomized controlled trial was conducted at 10 community clinics and 10 pharmacies in Yaoundé, Cameroon, between October 1998 and September 2000, with six months of follow-up. Participants included 1,251 women, excluding sex workers, who were being treated for or had symptoms of sexually transmitted infections. Three women were excluded from the gel group (0.5%) and seven from the condom group (1%) because of no follow-up data. Study participants were issued nonoxynol-9 gel (100 mg) and condoms or condoms only.
In evaluating the effects of the nonoxynol-9 gel on urogenital gonorrhea and chlamydial infection, the investigators found no difference in the incidence of these combined infections for women in the nonoxynol-9 gel group compared with women in the control group. They also noted a slightly higher rate of urogenital gonorrhea in the N-9 group. While safe to use, the spermicide gel did not protect against STD infection, they concluded.
The results of the research are consistent with an earlier study conducted in Cameroon among commercial sex workers, which examined use of nonoxynol-9 film.3 (Contraceptive Technology Update reported on preliminary results from this investigation in the article "Search continues for female-controlled prevention" in the June 1997 issue of STD Quarterly, p. 1.)
While research is promising on the microbicide front, no product has yet moved from the research pipeline to the drugstore shelf. (CTU reported on advancements in microbicide investigations in two 2002 issues: "2 trials will examine capability of microbicide," April 2002, p. 41; and "Progress under way on the microbicide front," January 2002, p. 5.) So what advice should clinicians offer now about nonoxynol-9?
Condoms continue to be the best available defense against STDs, says Michael Rosenberg, MD, MPH, clinical professor of obstetrics and gynecology at the School of Medicine and adjunct professor of epidemiology at the School of Public Health, both at the University of North Carolina at Chapel Hill, and president of Health Decisions, a Chapel Hill private research firm specializing in reproductive health.
"I believe the word to patients should be that these products probably do not provide protection against STDs, and thus concern about STDs should strongly indicate the use of condoms," says Rosenberg.
References
1. Roddy RE, Zekeng L, Ryan KA, et al. Effect of nonoxynol-9 gel on urogenital gonorrhea and chlamydial infection. JAMA 2002; 287:1,117-1,122.
2. Richardson BA. Nonoxynol-9 as a vaginal microbicide for prevention of sexually transmitted diseases. JAMA 2002; 287:1,171-1,172.
3. Roddy RE, Zekeng L, Ryan KA, et al. A controlled trial of nonoxynol-9 film to reduce male-to-female transmission of sexually transmitted diseases. N Engl J Med 1998; 339:504-510.
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