Benzodiazepines became widely available for medical purposes in the 1960s and replaced barbiturates in treatments of many conditions. Benzodiazepines proved themselves less prone to abuse than barbiturates, in addition to being safer—accidental overdose is unlikely because the amount needed for a medical effect is so much smaller than a poisonous amount. In addition to reducing anxiety, benzodiazepines may improve quality of sleep—from fighting insomnia to eliminating sleepwalking. This class of drugs is also used to calm people and to treat convulsions. Some users experience mild euphoria.
As might be expected with drugs that promote sleep, benzodiazepines can worsen reaction time, vigilance, and thinking abilities and therefore should be used cautiously if a person is operating dangerous machinery such as an automobile.
Problems may also develop for persons who are already unsteady on their feet, such as elderly persons prone to falling. The substances can also cause memory trouble, typically difficulty in recalling recent experiences. Headache, peevishness, confusion, and tremors may occur. In unusual cases rageful outbursts may occur. These are “paradoxical reactions,” meaning they are the opposite of what would be expected from the drug. Expressions of rage possibly emerge because the drug reduces anxiety in a person who is angry about something, and less anxiety can lead to less inhibition against doing something.
Over a 12-year span a practitioner observed patients taking benzodiazepines to treat serious sleep problems such as night terrors and sleepwalking. The practitioner found that 2% of this population (not 2% of all patients but just those using benzodiazepines against these sleep disorders) occasionally abused them, and this population base included persons with a previous history of drug abuse; thus we can expect benzodiazepine abuse to be even lower in a general population. Among persons treated for drug abuse, benzodiazepines are among the least-abused substances. Experiments giving free access to benzodiazepines to persons undergoing treatment for drug abuse revealed little interest in those compounds.This class of depressants can be highly popular among special populations, however. One study noted that 30% of alcoholics were using benzodiazepines. When benzodiazepines were given to rats in experiments, the animals’ consumption of alcohol increased, suggesting that human benzodiazepine usage might increase alcohol’s appeal. Although benzodiazepines are administered to treat alcohol withdrawal, combining the two substances recreationally is a dangerous mix that can prove fatal.
Different benzodiazepines have differing attractiveness to abusers. Measured by amount of misuse, claims made by misusers about drug effects, mental and physical effects verified in scientific experiments, and impressions reported by medical caregivers, diazepam is considered to have one of the greatest potentials for abuse. Alprazolam and lorazepam have similar, but lower, risk. Halazepam and oxazepam seem to be among the least risky for abuse.
Tolerance to some benzodiazepine effects can develop (many details are in this book’s alphabetical section). Dependence can also emerge, with a withdrawal syndrome similar to those of alcohol and barbiturates. Often the syndrome may be avoided by gradual reduction of dosage.
Small studies have found that women who use benzodiazepines during pregnancy produce infants who are smaller than normal. Children in one of these studies rapidly caught up in some growth perimeters, but at the age of months head size still remained smaller than normal. Facial deformities were common. The children had persistent trouble with muscle control. Similar findings in another small study included mental retardation, but still another study noted that such children also had heavy fetal exposure to alcohol, exposure that is known to produce mental retardation. Thus the actual role of benzodiazepines was unclear.
Some of these reports did not track outcomes past infancy. Research tracking children up to four years of age found that early problems attributed to benzodiazepines cleared up in most of them. When teachers were asked to evaluate schoolchildren who had fetal exposure, the instructors found no difference between them and classmates.
Researchers who investigated the outcome of thousands of pregnancies found no evidence that benzodiazepines cause cleft palate. A large study involving hundreds of pregnancies found birth defects to be no more likely among women who used benzodiazepines than among women who did not use them; and even when malformations occurred, no particular kind of birth
defect tended to appear in benzodiazepine offspring. Drugs that cause fetal harm generally cause particular types of damage; lack of a particular type with benzodiazepines suggests that the drug was not the cause of observed malformations. Some investigators believe they have detected a particular birth defect pattern, but such findings have been questioned. As the twentyfirst century began, a research team reported evidence that benzodiazepines may damage fetal brain development. Science has not yet rendered a verdict on the safety of benzodiazepines during pregnancy. Infants with fetal exposure can be born dependent on this type of drug. It passes into breast milk, but the amount from lower-dosage levels probably has no effect on nursing infants.
For information about specific benzodiazepine class depressants, see alphabetical listings for: alprazolam, chlordiazepoxide, clonazepam, clorazepate, diazepam, estazolam, flunitrazepam, flurazepam, halazepam, lorazepam, midazolam, oxazepam, prazepam, quazepam, temazepam, and triazolam.