Amphetamines
There are many drugs derived from amphetamine. Although amphetamine itself has been abused for many years around the world, a derivative called methamphetamine is far more popular as an illicit drug. Amphetamine arose from the desire of pharmacologists to find a substitute for ephedrine, the active ingredient in a group of herbs that have been used for thousands of years. Ephedrine is used today to dilate bronchial passages in treatment of asthma and this was one of the early uses of amphetamine. Amphetamine has also been used in the treatment of narcolepsy, a disease that causes its victims to fall asleep suddenly many times a day. It has also been used as an appetite suppressant and in the treatment of hyperkinesia, a disease that causes hyperactivity, mainly in children. Although still in Federal Schedule II, amphetamine is no longer widely prescribed for any of these purposes, having been replaced by drugs that are more effective with fewer side effects. Figure 13.1 shows the chemical structures of amphetamine and methamphetamine. In the 1960s, amphetamine and methamphetamine began to be widely abused for their stimulant properties. Instead of taking the drugs orally, which was the pre ferred route of administration for pharmaceutical users, abusers started taking them intravenously, which magnified their effects. Even today, clandestine methamphetamine laboratories flourish in many parts of the country. There are many routes to the preparation of methamphetamine and they can be found in underground publications and on the web. Because of its potent stimulant effects, methamphetamine has been called “speed” since the 1960s and the stimulants in general are called “uppers.” In recent years, the widespread abuse of the amphetamines has led to increasingly tighter control of legitimately manufactured doses, so more of the abused drugs have been made clandestinely. In an attempt to overcome the unpleasant habit of intravenous injection of these drugs, some users developed a smokeable form of methamphetamine called “ice.” Ice is made by slowly evaporating a solution of methamphetamine, forming large crystals. One of the forms of clandestine methamphetamine tablets is shown in Figure 13.2. There are a number of synthetic routes to manufacture amphetamine. As new ones crop up, the Federal Government responds by putting some of the precursors under control, making them more difficult to obtain. Clandestine chemists then develop new ways to manufacture “meth.” An example of this phenomenon is the simple synthesis of methamphetamine from pseudoephedrine, an over-the-counter allergy medicine. Combining this with lithium, which can be obtained from small batteries, and ammonia that can be obtained from farms, where it is used in the manufacture of fertilizers, forms methamphet amine. The ease of obtaining these materials turned clandestine methamphetamine manufacture into an epidemic during the 1990s and 2000s. Finally many states and the Federal Government retaliated by putting pseudoephedrine behind pharmacy counters and requiring purchasers to furnish identification and sign for the drug. People who illegally manufacture methamphetamine did not want to have to identify themselves and thus, this method of meth manufacture has been drastically curtailed. As a result, there has been a return to previous times when most methamphetamine entered the United States from large, well-organized laboratories located mainly in Mexico. There is some disagreement as to whether amphetamine and methamphetamine are addictive. It is now generally believed that when taken intravenously, these sub stances become addicting, whereas when taken orally or smoked, they cause strong psychological dependence, but not addiction.
FIGURE 13.1 The chemical structures of amphetamine and methamphetamine. Note that the only difference between these two substances is that the amine group in methamphetamine has a methyl (CH3) group. This is enough to alter the pharmacology of the molecule.
FIGURE 13.2 Clandestine Methamphetamine Tablets. These have been around for more than 50 years. They used to be called “minibennies” or “cartwheels” on the street. There have also been a number of knockoffs of these tablets, many of which contain caffeine.
