There are at least 20 opiates available in the United States (28). They act by binding to a variety of receptors that can influence mood, respiration, pain, blood pressure, endocrine function and gastrointestinal function. The desire to use them may be based on one or more of the following factors: positive reinforcement (desire for the "high") or negative reinforcement (desire for alleviation of pain or discomfort, including that of withdrawal).
Heroin is the most rapidly acting of the commonly abused opioids. Problems from its use include addiction itself, transmission of infection through shared injection equipment including hypodermic needles, syringes or rinse water, and the risk of adverse effects from contaminants.
The most effective treatment for heroin addiction is methadone maintenance at an adequate blocking dose (generally 60-120 mg/day). An alternative, recently approved by the FDA, is levo-alpha acetyl methadol or LAAM, a long-acting opioid agonist that may be administered as infrequently as every three days. Other agonists being developed include buprenorphine, which may be easier to withdraw from than methadone.
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Cocaine abuse has reached epidemic levels in this country (29). The drug's addictive potential results from its direct action on the reward pathways in the brain.
Cocaine can be taken intranasally ("snorted") or intravenously. However, the route of administration associated with the highest addictive potential (due to causing the most rapid rise in brain levels) is smoking (heated and inhaled). To be smoked, cocaine must be converted to "freebase" or "crack." The user experiences an intense high within seconds. When these effects dissipate after a few minutes (due to the rapid disappearance from the brain), the user feels anxious, depressed and paranoid--and craves another "hit."
There is no standardized treatment for addiction to stimulants such as cocaine. Options include abstinence and psychotherapy, mostly based on the "12-steps", as well as cognitive/behavioral approaches.
Amphetamines are indirect catecholamine agonists that cause the release of newly synthesized norepinephrine and dopamine; they may also affect serotonergic and other neuropeptide systems . Since their development, they have been widely used for their ability to combat fatigue, increase alertness, and suppress the desire for food. Chronic high-dose abuse can result in toxic pathophysiologic changes, including central changes (paranoid psychosis, aggression, impaired judgment) and peripheral (cardiovascular hypertension, slowing of cardiac conduction, hyperpyrexia).
Treatment of amphetamine addiction, like that for cocaine addiction, has not been standardized. Pharmacotherapy may be useful, probably by reversing or compensating for long-term residual neuroadaptations. Agents being evaluated include dopamine agonists and antidepressants, including fluoxetine. Another option is behavioral therapy.
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Nonmedical use of sedatives has been reported in 3.5 percent of the population and of tranquilizers in 5.1 percent . Abuse of drugs in this category generally involves benzodiazepines, since short-acting barbiturates and non-barbiturate hypnotics are generally less available . Use of a benzodiazepine at even the therapeutic dosage for a month or more can produce physical dependence (especially with alprazolam). Thus, during treatment, it is important not to discontinue the drug abruptly, which may cause a potentially fatal withdrawal syndrome (Wesson). Instead, these drugs may be discontinued by gradually tapering the dosage or (except in the case of triazolobenzodiazepines such as triazolam and alprazolam) by substituting a barbiturate or longer acting benzodiazepine and then gradually withdrawing the substitute.
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These agents are used illegally to enhance physical appearance, athletic performance, and fighting ability. Nonmedical use has been reported in children starting in the fourth and fifth grades, mostly by males, including students and nonstudent athletes such as weightlifters and bodybuilders. Adverse effects include a variety of physical effects on the cardiovascular, hepatic, and reproductive systems and psychiatric effects including episodes of depression, mania, psychosis, delirium, and marked aggressiveness. Whether use of these drugs may be associated with physical dependence is unclear; however, some users persist despite adverse consequences. The goal of treatment for all nonmedical uses is abstinence, with attention during initial abstinence to signs of withdrawal, and provision of supportive therapy.
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Although use of marijuana has declined since the heyday of the drug culture in the 1970s, it is still part of the lives of millions of Americans (31). Hemp products such as marijuana and hashish contain a number of active lipid-soluble cannabinoids, the most psychoactive being delta-9-tetrahydrocannabinol (THC).
Although marijuana may be ingested in a drink or in food, by far the most common route of administration is smoking. Smoke from marijuana or hashish contains various pyrolysis products and more tar than equivalent amounts of commercial tobacco. Therefore, smoking marijuana can cause bronchitis and increase the risk for respiratory infections and cancers.
Addictive behavior patterns occur rarely, even with heavy use of marijuana. Likewise, dangerous physical reactions are uncommon; the main physiologic effects of marijuana are increased appetite and a faster heartbeat, which is likely to be a problem only for persons with cardiovascular disease. However, the drug's possible psychological effects, such as amotivational syndromes, as well as known psychomotor effects on driving ability still raise considerable concern.
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Since 1972, abuse of phencyclidine (PCP; "angel dust") has increased dramatically and episodically in several waves. The drug was developed in the 1950s as an anesthetic. However, because as many as half of patients given PCP anesthesia developed severe intraoperative reactions including agitation and hallucination , its use is now limited to veterinary applications. In 1993, 1.4 percent of high school seniors reported using PCP in the past year, most within the preceding month [MTF]. The drug is most commonly used by persons between 12 and 25 years, among whom its popularity waxes and wanes. PCP seems to gain and lose popularity rapidly in a given locale. (Reference: Community Epidemiology Work Group (CEWG) Proceedings)
PCP is often smoked mixed with a leaf material (tobacco, marijuana). Even extremely low doses can precipitate a schizophrenia-like psychotic state. Death may occur, usually related to external events precipitated by drug use, including homicides, suicides, and accidents. There is no specific treatment for PCP intoxication; symptomatic management usually involves sedation with benzodiazepines and haloperidol.
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Hallucinogens, also known as psychotomimetics and/or psychedelics, are a diverse group of extremely potent substances that generally produce stimulation at very low doses and hallucinations, delusions, depersonalization, and unpredictable behavior at higher doses.
LSD became popular in the youth counterculture of the sixties and seventies. The loss of many young people from productive activities caused alarm and even hysteria among much of society. In consequence, early hallucinogen research was abruptly abandoned, despite the claims of some psychotherapists that LSD and other hallucinogens might be useful adjuncts to therapy. It has recently been suggested that ibogaine, a hallucinogen derived from Tabernanthe iboga, a West African shrub, may be useful in the interruption of the addictive process. Years ago, Bill W., one of the founders of AA, made a similar claim about LSD.
Addiction to hallucinogens is almost unknown, and tachyphylaxis (very rapid development of extreme tolerance) prevents them from being abused for more than a few consecutive days. However, these drugs can cause extreme, long-lasting adverse neuropsychiatric effects, including post-hallucinogen perceptual disorders or schizophrenia-like syndromes in vulnerable persons. Since the seventies, hallucinogens have remained popular among fans of certain music groups and may be increasingly popular among teenagers, especially at large electronic music and light shows known as "raves."
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Although the percentage of the population who engage in heavy drinking has decreased from 6.5 in 1985 to 5.3 in 1991, alcohol consumption remains a subject of considerable concern (1). The 10 percent of the population who drink the most heavily account for half the alcohol consumed in this country (1). Most abusers of illicit drugs have abused alcohol in the past or will eventually do so.
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Smoking kills more than 1,000 Americans every day. The cost of tobacco use to the nation is estimated to be $72 billion, including treatment expenses and lost productivity. Since the middle 1960s, cigarette consumption has declined markedly in the overall population. However, tobacco use among some adolescents and young adults is actually increasing, in part due to the vulnerability of this audience to age-specific marketing devices [Reference: Difranza et al. RJR Nabisco's cartoon camel promotes camel cigarettes to children. JAMA 1991;266:3149-53.] Because the adverse effects of smoking become manifest over decades, young people are particularly unlikely to appreciate the reasons not to smoke.
Treatment of nicotine dependence can be very effective when pharmacotherapy (ie, a transdermal nicotine patch) is combined with basic office counseling techniques. Efficacy is further improved when formal group programs using behavioral and cognitive relapse-prevention therapy are utilized.
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Inhalant refers to the common mode of administration rather than a particular category of drug. The agents used in this manner consist of a variety of inexpensive, readily available volatile substances that provide a high; they include medical anesthetic gases (ether, chloroform, halothane, nitrous oxide); industrial or household solvents (paint thinners, degreasers, solvents in glue); art- and office-supply solvents (correction fluid, solvents in marker pens); gases used in household or commercial products (butane lighters, gasoline, whipping cream dispensers, electronic equipment dusters and cleaners, refrigerant replenishers); household aerosol propellants (as in paint, hair spray, and fabric-protector spray); and aliphatic nitrites ("poppers"). . Note that smoked drugs are excluded from this category.
Inhaling volatile substances may cause considerable physical damage, including peripheral nerve damage (hexane), hepatotoxicity (chlorohydrocarbons), renal toxicity (probably toluene), leukemia (benzene); and organic brain syndromes. The specifics vary with different inhalants. The family physician should be alerted to the possibility of inhalant abuse by the telltale volatile odors; other signs include stupor, decreased cognitive abilities, and freeze burns from nitrous oxide.