Drug Abuse - Depressant drugs

Making up a second class of medically useful drugs that are also widely abused, the depressants act as sedatives on the central nervous system (CNS). They may also act as hypnotic, or sleep-inducing, agents.

The depressants include mainly the barbiturates, which are both sedative and hypnotic, and the tranquilizers, which can calm without producing sleep. Though they are available as main or secondary constituents of more than 80 brand name preparations, the barbiturates are readily abused.

Tranquilizers act selectively on the brain and the central nervous system. Divided into major and minor tranquilizers, these drugs are similar to barbiturates in many ways, including their sedative or calming effect. The major tranquilizers, called neuroleptics because they are useful in the treatment of mental disorders, are haloperidol and chlorpromazine . These drugs lead to virtually no addiction or dependence even in long-term therapy.

The minor tranquilizers, among them meprobamate (Miltown), chlordiazepoxide (Librium), and diazepam (Valium), are, by contrast, highly addictive. Abusers take such drugs to achieve euphoric states as well as to offset the effects of alcohol, amphetamines, and other drugs.


Barbiturates have many legitimate uses. For example, they may be prescribed to overcome insomnia, reduce high blood pressure, alleviate anxiety, treat mental disorders, and sedate patients both before and after surgery. Barbiturates may help to bring epileptic and other convulsions under control.

Barbiturates are metabolized, or broken down chemically, by the liver. They are then eliminated by the kidneys at different speeds depending on their types: slow- or long-acting, intermediate and short-acting, or ultra-short-acting. The first of these, primarily phenobarbital and barbital, take effect on the brain in one to two hours and last for six to 24 hours. The intermediate and short-acting barbiturates, including secobarbital and pen-tobarbital, take effect in 20 to 45 minutes and last five to six hours. The best known of the ultra-short-acting drugs, sodium pentothal or thiopen-tal, can produce unconsciousness in a few minutes. Used mostly in hospitals as an anesthetic, pentothal is also injected by dentists to produce instant unconsciousness.


Barbiturate abusers usually select the ultra-short-acting form of the drug because of the rapid action. Abusers as a group generally fall into four categories, with some overlap.

The “silent abuser” takes sleeping pills at first to get some sleep, probably with a physician's prescription. Progressively, the drug helps the abuser to deal with tension and anxiety. Indulging at home, he or she finds the barbiturates producing an alcohol-like high, with slurred speech, confusion, poor judgment and coordination, and sometimes wild emotional swings. Eventually the abuser is obtaining the drug through illicit channels. Some may end up spending most of their time in bed.

A second group, taking barbiturates for stimulation, has already developed a high tolerance that makes drug stimulation possible. Some other abusers find that the drug releases inhibitions.

Made up mostly of young people who are experimenting with various drugs, a third group uses barbiturates to “come down” from an amphetamine high. Members of this group may find themselves in a vicious cycle of stimulation and sedation. To obtain both effects at once, some abusers take the barbiturate-amphetamine combination in the same swallow—a so-called “set-up.”

A fourth group, abusers of heroin and other narcotics, uses barbiturates as a substitute when drugs of choice are not available. They may also combine barbiturates with heroin to prolong its effect. In one hospital surveyed, 23 percent of the narcotics users said they were also dependent on barbiturates.

Effects and Dangers

Barbiturate abuse is generally considered to be far more dangerous than narcotic abuse. Every year brings some 3,000 deaths from barbiturate overdose, accidental or intentional. For such reasons many physicians believe barbiturates are the most dangerous of all drugs. Chronic abuse can lead to psychological dependence and increased tolerance, followed often by physical dependence of a particularly anguishing kind.

Abrupt withdrawal from barbiturates can be much more dangerous than withdrawal from heroin. Within a day the abuser withdrawing from barbiturates may experience headaches, muscle twitches, anxiety, weakness, nausea, and blood pressure drops. If the abuser stands up suddenly he or she may faint. Delirium and convulsions may come later. The latter can be fatal. Thus the withdrawal must always be undertaken under medical supervision. Even with supervision, a withdrawal from barbiturates may take two months.

Abuse of barbiturates presents other dangers. Unintentional overdosing frequently occurs when a person takes a regular dose to get to sleep and then remains awake or awakens soon afterward; tired and confused, the person may take another or repeated doses. Death may result. Mixing barbiturates and alcohol can produce the same outcome.

Other Barbiturate-Type Drugs

Some depressants are chemically unrelated to the barbiturates but have similar effects. These include glutethimide , ethchlorvynol (Placidyl), and methyprylon (Noludar). These too lead to tolerance when abused and sometimes to psychological and physical dependence.


The minor tranquilizers are manufactured as capsules and tablets in many sizes, shapes, and colors. They may also be purchased in liquid form for injection. Used legitimately to treat emotional tension and as muscle relaxants, these tranquilizers have high abuse potential because they produce both psychological and physical dependence. Tolerance develops with prolonged abuse.

Varieties of abused drugs

Varieties of abused drugs
Name Form Drug
amphetamine methamphetamine capsule, pill, liquid, powder, tablet, lozenge; swallowed stimulant
barbiturate sleeping pills, capsules, tablets; swallowed; injected depressant, sedative
cocaine white powder; sniffed, smoked, injected stimulant, local anesthetic
hashish resin; smoked relaxant, euphoriant, hallucinogen (in large or strong doses)
heroin powder; injected, or sniffed narcotic
inhalants (for example, gasoline, paint, glue, aerosols, amyl nitrite) aerosols, volatile substances, solvents; sniffed
LSD (d-lysergic acid diethylamide) tablet, capsule, liquid; swallowed hallucinogen (psychedelic)
marijuana, marihuana dried leaves; smoked relaxant, euphoriant, hallucinogen (in large or strong doses)
mescaline tablet, capsule; swallowed hallucinogen
PCP powder; smoked, swallowed anesthetic (used only with animals)

Miltown, Librium, and Valium produce effects similar to those of barbiturates. But the minor tranquilizers act more slowly and have longer duration. Once considered completely harmless, these drugs came into such vogue that in the 1970s the federal government intervened. Both Valium and Librium as well as some other drugs were placed under federal control. From 1975 on anyone requiring a prescription for these drugs was limited to five prescription refills within a six-month period following the initial prescription. If more of the medication was required after that, a new prescription had to be written.

Withdrawal from the minor tranquilizers can be as dangerous and painful as withdrawal from barbiturates. Combining the tranquilizing drugs with others, including alcohol, is a highly dangerous form of abuse. Each drug reinforces the effects of the other. The result may be greater than the combined effects of the different drugs.

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