Amyl nitrite has a long history of safe medical use in treating angina, as well as an antidote to cyanide poisoning. Amyl nitrite and several other alkyl nitrites which are used in over-the-counter products, such as air fresheners and video head cleaners, are often inhaled with the goal of enhancing sexual pleasure. These products have also been part of the club culture from the 1970s disco scene to the 1980s and 1990s rave scene.
Direct, concentrated inhalation of amyl nitrite and the other light alkyl nitrites leads to a non-specific relaxation of smooth muscle, resulting in coronary vasodilation and decreased systemic vascular resistance and left ventricular preload and afterload. Sir Thomas Lauder Brunton (14 March 1844-16 September 1916), a Scottish physician, is famously-associated with the use of amyl nitrite to treat angina pectoris.
Additionally, the light alkyl nitrites cause the formation of methemoglobin wherein, as an effective antidote to cyanide poisoning, the methemoglobin combines with the cyanide to form nontoxic cyanmethemoglobin. First responders typically carry a cyanide poison kit containing amyl nitrite, such as the popular Taylor Pharmaceutical Cyanide Antidote Kit.
TIME Magazine and The Wall Street Journal reported that the popper fad began among homosexual men as a way to enhance sexual pleasure, but "quickly spread to avant-garde heterosexuals" as a result of aggressive marketing. A series of interviews conducted in the late 1970s revealed a wide spectrum of users, including construction workers, a "trendy East Side NYC couple" at a "chic NYC nightclub", a Los Angeles businesswoman "in the middle of a particularly hectic public-relations job" (who confided to the reporter that "I could really use a popper now."), and frenetic disco dancers amid "flashing strobe lights and the pulsating beat of music in discos across the country".
User surveys are hard to come by but a 1988 study found that 69% of men who had sex with men in the Baltimore/Washington DC area reported they had used poppers, with 21% having done so in the prior year. The survey also found that 11% of recreational drug users in the area reported using poppers, increasing to 22% among "heavy abusers", with an average age of first use of 25.6 years old. Both survey groups used poppers to "get high", but the men who had sex with men were more likely to use them during sex. It was reported that this group reduced usage following the AIDS epidemic, while the drug-users had not. A 1987 study commissioned by the US Senate and conducted by the Department of Health and Human Services found that less than 3% of the overall population had ever used poppers.
Originally marketed as a prescription drug in 1937, amyl nitrite remained so until 1960, when the Food and Drug Administration removed the prescription requirement due to its safety record. This requirement was reinstated in 1969 after observation of an increase in recreational use.
Other alkyl nitrites were outlawed in the USA by Congress through the Anti-Drug Abuse Act of 1988. The law includes an exception for commercial purposes. The term commercial purpose is defined to mean any commercial purpose other than for the production of consumer products containing volatile alkyl nitrites meant for inhaling or otherwise introducing volatile alkyl nitrites into the human body for euphoric or physical effects. The law came into effect in 1990. Visits to retail outlets selling these products reveal that some manufacturers have since reformulated their products to abide by the regulations, through the use of the legal cyclohexyl nitrite as the primary ingredient in their products, which are sold as video head cleaner, polish remover or room odorants. (Cyclohexyl nitrite is technically not a member of the class of alkyl nitrites encompassed by the law, but as a result of the Federal Analog Act, its status remains in question.)
Amyl nitrite, manufactured by Burroughs Wellcome (now GlaxoSmithKline) and Eli Lilly and Company, was originally sold in small glass ampoules that were crushed to release their vapors, and received the name "poppers" as a result of the popping sound made by crushing the ampule. Today, generic-like street names include 'poppers', RUSH,, Locker Room, Snappers, and Liquid Gold. Many brand names exist and are in use in different localities.
Inhaling nitrites relaxes smooth muscles throughout the body, including the sphincter muscles of the anus and the vagina. Smooth muscle surrounds the body's blood vessels and when relaxed causes these vessels to dilate resulting in an immediate increase in heart rate and blood flow throughout the body, producing a sensation of heat and excitement that usually lasts for a couple of minutes.
Alkyl nitrites are often used as a club drug or to enhance a sexual experience. The head rush, euphoria, and other sensations that result from the increased heart rate are often felt to increase sexual arousal and desire. At the same time, the relaxation of the sphincters of the anus and vagina can make penetration easier. It is widely reported that poppers can enhance and prolong orgasms.
While anecdotal evidence reveals that both men and women can find the experience of using poppers pleasurable, this experience is not universal; some men report that poppers can cause short-term erectile problems.
In a 2006 article published in London's The Independent titled "Drugs: the real deal", it was revealed that the first ranking based upon scientific evidence of harm to both individuals and society, devised by British-government advisers, showed that "Poppers" pose little potential harm to individuals or to society.
It is suggested that taking Viagra with nitrites could cause a serious decrease in blood pressure, leading to fainting, stroke, or even heart attack. Poppers can also increase intraocular pressure, resulting in the medical condition glaucoma. In reference to vision loss, a published case concluded "No similar cases have been described in the more than 100-year history of pharmacological use of amyl nitrite for angina pectoris, and pharmacologically it is hard to point out a rationale behind the sequential visual loss". High doses of nitrites may cause the rare disorder methemoglobinemia, especially in individuals predisposed towards such a condition. Methemoglobinemia is characterized by cyanosis, shortness of breath, fatigue, altered mental status, coma, and even death. Overdoses are treated with the compound methylene blue.
There has also been a suggestion that poppers may weaken the immune system, however any damage is undone within a few days of halting use. Other risks include burns if spilt on skin, loss of consciousness, headaches, and red or itching rashes around the mouth and nose.
Suggestions of a link between poppers and either AIDS, HIV-infection or an AIDS-related cancer called Kaposi's Sarcoma have been made and are a subject of on-going debate. Several researchers have demonstrated a statistical correlation between popper use and HHV-8-infection and development of Kaposi's Sarcoma. However the most recently published peer-reviewed English-language overview of research on the health risks of poppers notes a lack of controlled trials. The correlation might therefore be accounted for by a bias among some popper users towards high-risk sexual behaviours. A 1992 article in The Lancet draws exactly that conclusion in a finding that the practice of insertive rimming explained excess rates of Kaposi's sarcoma. In a 1986–1988 series of study reviews and technical workshops with leading authorities, mandated by the US Congress, it was concluded that nitrites are not a causal factor in AIDS infection or Kaposi's sarcoma. A study that followed 715 gay men for eight and a half years published in the Lancet in 1993 rejected any causal relationship between AIDS and poppers, but noted a correlation between HIV infection and poppers. Anal sex was also correlated. However, a meta review of 30 research articles examining HIV infection risk and club drug use showed some evidence for poppers being a risk factor for HIV infection but considered further research was necessary.
Some health authorities now mandate point of sale warnings. Some health departments and AIDS prevention agencies have issued alerts about poppers use being associated with HIV transmission. In 2007 Seattle Health Department issued a poppers alert cautioning "be cautious about the information on the internet. Websites that sell poppers are not accurate sources of health information." However, reputable medical sites such as the online version of the Merck Manual of Diagnosis and Therapy continue to report that there is little evidence of significant hazard associated with inhalation of alkyl nitrites. Aside from the issue of HIV/AIDS, a 1983 U. S. Consumer Product Safety Commission investigation Briefing Package stated that "Available injury data did not indicate a significant risk of personal injury or illness from room odorizer abuse."