120 Diazepam
more tobacco cigarettes people smoke, the less drowsy diazepam makes them.
Body weight also affects diazepam actions, with drug build-up and elimina-
tion taking longer in bodies of fatter people. Experimenters have even found
that drug effects can vary by time of day; at night diazepam prolongs the
presence of an ibuprofen dose.
Cancer. Experimentation shows diazepam to have potential for causing
cancer in mice, results causing researchers to suspect the same possibility in
humans. Tests with rats, gerbils, and hamsters produced no cancer risk. Ex-
amination of medical records from almost 13,000 diazepam users found no
link to a higher cancer rate. Several other investigations found no connection
between the drug and assorted human cancers, but results have been mixed
on association with ovarian cancer.
Pregnancy.Hamsters receiving the drug during pregnancy can produce off-
spring with cleft palate and other skull abnormalities. Similar results are seen
in mice, particularly if cocaine is used as well. Chicken embryos exposed to
diazepam develop malformations. Diazepam experiments with rats have re-
sulted in fewer pregnancies and higher death rates for pups. Some rat exper-
iments produce birth defects and some do not; size of dose may be important.
If pregnant mice receive the drug, their male offspring may have difficulty
with sexual functioning as adults. (In contrast, the drug is used for treating
impaired male sexual functioning in humans.) Rodent offspring may suffer
from compromised immune systems. They also may act more nervous than
pups who lack fetal exposure, although rats that have no fetal exposure, but
instead receive multiple doses soon after birth, act less uneasy in later life
after dosage has stopped. A number of rodent studies find that prenatal ex-
posure to diazepam may produce assorted behavioral effects that do not ap-
pear until adolescence or adulthood. Those effects are measured by various
tests (running mazes and the like) that are difficult to extrapolate to human
experience, but the point is that diazepam’s effects may be unapparent in
newborns and take years to emerge.
A study of 689 pregnant women taking assorted antidepressants was unable
to attribute any birth defects to diazepam, and the same results came from a
smaller study; but nonetheless the drug is suspected of causing malformations.
Measurements from pregnant women indicate that diazepam passes to the
fetus and builds up there; blood levels of the drug in newborns can be higher
than the mother’s. Some researchers find that the drug slows fetal brain de-
velopment. A case report notes severe multiple malformations in an infant
whose mother used diazepam during pregnancy but does not establish cause
and effect. Researchers tracked medical histories of several thousand women
whose babies had major malformations and found an association between
diazepam and cleft lip, the association becoming even stronger if women had
smoked while taking diazepam during pregnancy. Additional research has
associated diazepam with birth defects involving the heart, stomach obstruc-
tion, and hernia. Association, however, does not prove cause and effect. In-
deed, other research has found no association between diazepam and cleft lip
or any other congenital malformation. One study found that newborns with
fetal exposure to diazepam tend to weigh less than normal, but they soon gain
weight and reach a normal level. Infants have exhibited withdrawal symptoms