Will Nonoxynol-9 Be a Good Microbicide Candidate?

One possible microbicide candidate is a chemical called nonoxynol-9. Originally developed to kill sperm, nonoxynol-9 has been shown to destroy bacteria and viruses that cause sexually transmitted diseases (STDs), including herpes, gonorrhea, chlamydia, and HIV in laboratory and animal studies. Nonoxynol-9 is a detergent originally formulated to kill sperm and is available in many concentration levels and formulations (gels, creams, foams, and film). Nonoxynol-9 is used in some lubricants and coats some latex condoms.

There has been little evidence that nonoxynol-9 provides protection against HIV outside of the laboratory and several studies have shown that when used often nonoxynol-9 may cause genital irritation. Additional studies have shown that spermicides using nonoxynol-9 can increase a woman's risk of certain vaginal infections (yeast infections, and bacterial vaginosis) and do not provide complete protection against STDs.

Recent studies have tried to determine if it would be effective in preventing HIV transmission. Several studies made public at the XIII International AIDS Conference in South Africa showed that women using lubrication containing nonoxynol-9 actually had a higher rate of HIV infection than those who used lubrication without nonoxynol-9. The researchers concluded that this was due to vaginal inflammation caused by nonoxynol-9. Critics pointed out that many of the women in the study were sex workers and used an unusually high amount of nonoxynol-9. Some people also questioned whether the small amount of nonoxynol-9 found on spermicidally lubricated condoms would have the same effect.

Since the World AIDS Conference, there has been increased evidence that a microbicide containing nonoxynol-9 may increase the risk of HIV transmission, when used frequently. However, when used for occasional use with condoms its potential to kill HIV or to increase risk for HIV transmission is unknown. While the FDA has decided not to stop the sale or distribution of condoms lubricated with nonoxynol-9 until further data is available, both the Seattle-King County and San Francisco departments of public health have decided to stop purchasing or distributing nonoxynol-9 containing condoms.