Inhalants

Types of Inhalants

Inhalants are somewhat difficult to categorize because it is not very well understood how they work in the body and there are many different types of chemicals and products that can be abused as inhalants. Nonetheless, it has been suggested that inhalants can be classified into three general categories on the basis of their pharmacological effects and how they are used: (1) alkyl nitrites; (2) nitrous oxide; and (3) volatile solvents, fuels, and anesthetics.

Alkyl nitrites are the least commonly used drugs of the inhalant class. The prototypical alkyl nitrite is amyl nitrite, which was used for the treatment of angina (chest pain) before the development of nitroglycerine. Amyl nitrite relaxes smooth muscle tissue and results in the dilation of blood vessels (vasodilation), which helps to increase blood flow to parts of the body. These effects are responsible for its therapeutic effect in treating chest pain by allowing more blood and oxygen to reach the heart. Unlike drugs from the other categories of inhalants, alkyl nitrites are not thought to be primarily used to produce intoxication or psychoactive effects per se, but rather to enhance sexual experiences. Vasodilation and smooth muscle relaxation (which might also result in sensations of warmth or lightheadedness) are thought to be the primary effects responsible for the recreational use of alkyl nitrites to enhance sexual experiences.

Amyl nitrite and other alkyl nitrites produced for recreational use came to be known as “poppers” because they were manufactured in ampoules or bottles that had to be “popped” open. After the availability of amyl nitrite for medical use decreased in the late 1960s in the United States, other alkyl nitrites such as butyl nitrite began to be manufactured for recreational use and sold in sex shops, or more covertly, as products not intended for human use (e.g., air freshener or cleaning fluid).

Nitrous oxide is a gaseous anesthetic and analgesic that is widely used in medical and dental practice. Nitrous oxide is considered to be in separate category than the volatile anesthetic drugs because it produces somewhat different effects. Nitrous oxide appears to produce less sedation and greater analgesic, euphoric, and psychedelic-like effects as compared to volatile anesthetic drugs. The mechanism of action responsible for the effects of nitrous oxide is not entirely clear, but it is thought to involve antagonism of N-methyl-D-aspartate (NMDA) receptors and facilitation of ?-aminobutyric acidA (GABAA) receptor signaling. Consistent with anecdotal and laboratory reports of euphoric effects after administration of nitrous oxide, it is commonly referred to as “laughing gas.” Scientific studies have shown that nitrous oxide has reinforcing effects and is self-administered by humans and nonhuman animals in the laboratory.

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