Warning: "Poppers" Return, More Evidence of Harm

John S. James
AIDS Treatment News #160, October 2, 1999

"Poppers" are nitrite inhalants which have been used in the gay community as a sexual aid. Following research reports that these chemicals might be contributing to immune problems in AIDS or to the development of Kaposi's sarcoma, they were banned in the United States in 1988. But now they are coming back, being sold allegedly for such purposes as removing fingernail polish, in sex clubs, bars, through the mail, and by advertisements in gay publications. One concern is that promoters of new preparations, in an effort to get around the law, could replace banned chemicals with substitute ones, with completely unknown effects when deliberately inhaled; one unlucky choice of ingredient could cause widespread damage. Efforts are under way to analyze inhalants now being sold to determine what they contain.

[The 1988 law, section 8 of the Consumer Product Safety Act, banned the manufacture for sale, distribution in commerce, or importation of various forms of "butyl nitrite." Manufacturers then substituted isopropyl nitrite, and in 1990 Congress amended the law to also ban "volatile alkyl nitrites that can be used for inhaling or otherwise introducing volatile alkyl nitrites into the human body for euphoric or physical effects." We do not know if the current products have substituted other chemicals in order to evade this language.]

In most of the world poppers are not illegal or regulated, and they have remained in widespread use in some countries.

According to Hank Wilson, a well-known AIDS activist with ACT UP/Golden Gate who fought poppers years ago and recently brought the current resurgence to our attention, one problem in alerting the gay community to the dangers is that some gay newspapers are reluctant to report negative news about poppers because they carry advertisements for these preparations. As a result, young people now entering the gay community often do not know that there ever was a health issue or controversy about the use of these drugs. (A San Francisco law requiring a warning sign where poppers are sold took effect in January 1984. But today the traffic is underground, so this warning law isn't working.)

The issue of poppers in the gay community first surfaced in 1981, and some observers suspected that poppers themselves might cause AIDS. Later, those theories were largely dismissed, but confusion occurred because some people thought the issue was finished. The remaining concerns are that poppers might be a cofactor in the development of AIDS, or could lead to relapse to unsafe sex, or make HIV infection more likely by causing changes in blood vessels(1), or possibly cause poisoning if unknown chemicals are substituted in an effort to evade the law. And some of the chemicals are known to degrade over time, so there could be harmful byproducts as well. Some researchers also suspect that the body may metabolize the nitrites to nitrosamines, which are strongly carcinogenic(1).

Because of the high profit margin -- it costs about 25 cents for the chemical which sells for about $10 retail -- this issue is expected to remain with us for some time.

Recent Studies of Popper Use

Poppers have not been conclusively proven to be harmful; absolute proof would require a large clinical trial with people randomly assigned to take a placebo or each of the various chemicals in use, clearly an ethical impossibility. One recent study(2), however, gave repeated doses of amyl nitrite to volunteers and found suppression of immune functions, especially of natural killer cells, following moderate inhalation. The number of these cells did not decrease, but their activity decreased about 30 percent, and remained low until several days after the use of the drug was stopped. (The volunteers were HIV-negative men who had used poppers previously. The researchers' institutional review board would not allow the test to be repeated on HIV-positive volunteers, because of the risk of harm their health.)

An epidemiological study in Vancouver published in May 1992(3) followed a cohort of 353 gay men and found that those who used nitrite inhalants were 2.3 times more likely to develop Kaposi's sarcoma than those who did not. Because such an association could be caused by factors other than the chemical effect of the nitrites (for example, those who used poppers might also have had more unsafe sexual contacts), the data was statistically adjusted for known HIV risk factors. Poppers use was still associated with increased risk of KS.

However, an English study of 65 gay men(4) failed to find an association between poppers use and KS.

An epidemiological study in Boston(1) found that poppers use increased the risk of HIV infection, especially during unsafe sex. And the same Vancouver research group mentioned above reported, at the 1991 International Conference on AIDS in Florence, that gay men who practiced unsafe sex were more likely to use poppers than those who did not(5).

Two 1990 articles from the U. S. National Institute of Drug Abuse(6,7) called nitrite inhalants a leading candidate as a cofactor for the development of KS in persons with AIDS, and urged physicians to encourage patients to avoid their use.

However, a report from the San Francisco City Clinic Cohort Study(8) did not find differences in nitrite use among AIDS patients with KS vs those who did not have KS.

A study of gay men in the Paris area found that poppers use was associated with increased risk of being HIV positive, even after the data was adjusted for known risk factors(9).

In an animal study, mice exposed to isobutyl nitrite 45 minutes a day for 14 days showed several kinds of immune suppression(10).

This list is far from complete; there are many other medical-journal articles on poppers, most of them reporting evidence of health risks. We only included the ones which were published in 1990 or later, and which seemed most important. Therefore our list entirely omits the earlier medical-journal warnings about poppers which led to the law against them in the United States.

Comment

We may never have final answers to the questions about health hazards of poppers; some of the articles cited here did not find evidence of harm. But the weight of the evidence strongly suggests that poppers are certainly not safe and probably do cause damage to health, especially to persons with HIV. Since these drugs are coming back into use despite the U. S. law against them, people will have to make their own decisions. It is important that the available information be widely circulated in the gay community and among other users of such inhalants.

Note: Anyone who wants to work on the poppers issue can call Hank Wilson at 415/441-4188, or write to him at 55 Mason Street, San Francisco, California 94102.

References