328 Nitrous Oxide
nitrous oxide is called nonflammable, when inhaled it can seep into the ab-
dominal cavity and bowels, mixing with body gases to create a flammable
combination. If ignited the result would be like setting off an explosive inside
the body; the danger is real enough that surgical personnel administering
nitrous oxide as an anesthetic have been warned about it.
As with many other drugs, effects of nitrous oxide can be influenced by
changes in setting. For example, volunteers who knew what to expect per-
formed better on tests than persons who had no information about what ni-
trous oxide would do to them.
Abuse factors.In tests of the drug’s appeal, people in general chose nitrous
oxide no more often than placebo; such lack of preference is a classic sign of
low addictive potential. One experiment revealed a catch to such findings,
however: Volunteers who enjoyed nitrous oxide effects chose it more often
than placebo, and volunteers who disliked the drug actions chose it less often
than placebo. Thus, overall in the general population the drug might be no
more attractive than placebo, but nonetheless some persons may find it cap-
tivating. Such a finding is consistent with drugs having high abuse potential,
such asheroin; so the fact that persons typically find no attraction in nitrous
oxide does not prove low abuse potential for nitrous oxide. Its nickname “hip-
pie crack” suggests that users have recognized an abuse potential. Nonethe-
less, a medical practitioner who administered the gas as a drug addiction
treatment said that in 15,000 cases not a single addict indicated subsequent
craving for nitrous oxide; such a patient population would be expected to
show particular susceptibility if given a substance with abuse potential. The
same practitioner notes that regardless of theoretical possibilities, 200 years of
experience demonstrate that nitrous oxide is among the least abused drugs.
Tolerance develops in rats. Human experimentation documents tolerance
developing to some effects (such as euphoria and pain relief) but not neces-
sarily to all.
Drug interactions.In an experiment comparing light drinkers of alcohol to
moderate drinkers, the moderate drinkers found nitrous oxide more appeal-
ing. One group of researchers found that alcohol boosts nitrous oxide effects
and that the drug combination creates effects produced by neither substance
alone. Those researchers concluded, however, that the combination was not
potent enough to have more appeal than nitrous oxide alone. That conclusion
assumes, of course, that drug abusers base their conduct on rational analysis
of scientific findings. In a similar experiment comparing users and nonusers
of marijuana, when given a choice neither group preferred nitrous oxide more
than a placebo, but nitrous oxide effects felt stronger to marijuana users. In
ratsketamineboosts effects from nitrous oxide. In a human medical context
that combination is routine and appears safe, but the combination causes brain
damage in rats. Persons usingmorphineor other opiates can experience mus-
cle rigidity when inhaling nitrous oxide, a situation that can interfere with
breathing.
Cancer.Studies do not indicate that nitrous oxide causes cancer in animals.
Whether the drug causes cancer in humans is unknown. Genetic damage sim-
ilar to the amount from daily smoking 10 to 20 cigarettes has been found in