22 The Encyclopedia of Addictive Drugs
greatest potentials for abuse.Alprazolamandlorazepamhave similar, but
lower, risk.Halazepamandoxazepamseem 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 with-
drawal syndrome similar to those of alcohol and barbiturates. Often the syn-
drome 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.^31 Children in one of
these studies^32 rapidly caught up in some growth perimeters, but at the age
of 18 months head size still remained smaller than normal. Facial deformities
were common. The children had persistent trouble with muscle control. Sim-
ilar findings in another small study^33 included mental retardation, but still
another study^34 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 track-
ing children up to four years of age found that early problems attributed to
benzodiazepines cleared up in most of them.^35 When teachers were asked to
evaluate schoolchildren who had fetal exposure, the instructors found no dif-
ference between them and classmates.^36
Researchers who investigated the outcome of thousands of pregnancies
found no evidence that benzodiazepines cause cleft palate.^37 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.^38 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.^39 As the twenty-
first century began, a research team reported evidence that benzodiazepines
may damage fetal brain development.^40 Science has not yet rendered a verdict
on the safety of benzodiazepines during pregnancy. Infants with fetal expo-
sure 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 alpha-
betical listings for:alprazolam,chlordiazepoxide,clonazepam,clorazepate,
diazepam, estazolam, flunitrazepam, flurazepam, halazepam, lorazepam,
midazolam,oxazepam,prazepam,quazepam,temazepam, andtriazolam.Opiate Class
Along with alcohol, opiates are the oldest known depressants. At one time
the termnarcoticreferred specifically and only to opiates, but when drug con-
trol laws were strengthened in the early twentieth century the language of