Properties of Inhalants

Inhalants are grouped into four categories (1) volatile solvents, (2) aerosols, (3) anesthetics, and (4) volatile nitrites. Most of these compounds are very commonplace products that were never intended to be inhaled to achieve intoxication. Today, more than 1,400 products are used as inhalants. 

Aerosols comprise compounds such as spray paints, hair sprays, pain-relieving sprays, deodorants, fabric-protector sprays, vegetable frying-pan lubricants, and hundreds of other everyday chemicals that are found in homes or are readily available commercially. Products that create an aerosol use propellants to keep tiny particles suspended in the air. For the most part these propellants, not the liquid product, are the chemicals abused. Virtually any aerosol product can be abused. 

Unlike the other inhalants discussed, volatile nitrites do not act by depressing the central nervous system and slowing down the body. Volatile nitrites function as vasodilators and muscle relaxants. Vasodilators make blood vessels dilate, or become wider. This increases the heart rate. Amyl nitrite is used medicinally as a treatment for heart patients with angina. 

These drugs are used recreationally in dance clubs where patrons sniff them on the dance floor to increase their enjoyment. Combining the beat of the music, rhythm, light shows, and dancing with inhalant use makes the experience more enjoyable for some users. Nitrites were also commonly used in sexual pleasure, particularly by homosexual males during sexual activity to intensify the experience. Unlike other inhalants, nitrite use has decreased considerably since 1979 among high-school students. 

These different inhalants are abused by sniffing, or inhalation by the nose, and huffing, or inhalation by the mouth. They produce similar intoxicating effects, including dizziness, disorientation, and hallucination. The intoxication by inhalants is quick, with a short period of excitation followed by drowsiness, lightheadedness, loss of inhibition, and agitation. Often the effects of inhalation are interpreted as euphoric or pleasurable. The period of intoxication can last from a few minutes to a few hours, and is usually followed by a hangover or headache. 

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Wood RW Stimulus properties of inhaled substances. Environ Health Perspect 26 69— 76, 1978... 

Glaser U, Hochrainer D, Steinhoff D. 1990. Investigation of irritating properties of inhaled CrVI with possible influence on its carcinogenic action. Environ Hyg 2 235-245. 

Contents An overview what are inhalants —History of inhalant use— Properties of inhalants — How do inhalants act —Abuse of inhalants— Consequences of inhalant abuse—Trends and use of inhalants—Treatment and prevention. 

Halsey. M.J. (1989) Physicochemical properties of inhalation anaesthetics, in General Anaesthesia, (eds J.F. Nunn eta/.). Butterworth. London. 

METHODS TO ASSESS PHARMACOKINETIC AND DYNAMIC PROPERTIES OF INHALATION DRUGS... 

Earlier we described how pharmacokinetic and dynamic properties of inhaled drugs are relevant for pulmonary selectivity. The assessment of pharmacokinetic and dynamic properties is consequently relevant for drug development and clinical practice. This section reviews some of the relevant techniques for assessing such properties. The available tools range from cell culture or isolated lung perfusion models to mucociliary clearance analysis, imaging techniques, and in vivo pharmacokinetic and dynamic analysis of the inhaled drug. 

Derendorf H. Pharmacokinetic and pharmacodynamic properties of inhaled corticosteroids in relation to efficacy and safety. Respir Med 1997 91(Suppi A) 22-33. 

Measurements of the quantity and quality of the aerosolized drug allow characterizing the dosing properties of inhalation devices in vitro. Multistage im-pactors are used to assess particle mass and mass distribntion of an aerosol, and methods are available to estimate the mass median aerodynamic diameter (MMAD) of the aerosol as well as the dose of delivered from and retained within an inhalation system. 

The physical properties of inhalational anesthetics are provided in Table 19.2. Note that desflurane, compared to other agents, has a boiling point that is close to normal room temperature and a vapor pressure that is close to atmospheric pressure at sea level. These properties dictated a new type of vaporizer that heats the agent to 39°C in order to meter the flow of desflurane vapor into the gas flow stream. The minimum alveolar concentration (MAC) of halothane, from Table 19.2 indicates that the agent is the most potent of the agents available today with desflurane as the least potent. 

Wood R.W. (1978) Stimulus properties of inhaled substances. Env. Health Persp. 26, 69-76. 

After considerations about the health-related properties of inhaled particles and their fate in the lung, this chapter will examine the role and usefulness of mineralogical analysis studies, the sampling and analytical techniques, the methodological limitations and the interpretation of the results. 

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