N
naltrexone A medication to treat opiate ADDIC-
TION. Naltrexone binds with opiate receptors in the
BRAIN, preventing opiate drugs from binding. This
action can block further effect of OPIATESalready in
the body or prevent the effect of opiates taken
after naltrexone is in the body. Naltrexone is a
treatment for addiction to opiates including pre-
scription NARCOTICSand illicit drugs such as HEROIN.
Naltrexone also helps reduce ALCOHOLcravings in
some people who are recovering from ALCOHOLISM.
Naltrexone is most effective in people who have
strong desire to remain abstinent from DRUG or
alcohol use and when starting DETOXIFICATIONas
part of a comprehensive SUBSTANCE ABUSE TREAT-
MENTprogram.
See also ILLICIT DRUG USE; LEVO-ALPHA ACETYL-
METHADOL (LAAM); METHADONE; PRESCRIPTION DRUG
ABUSE; WITHDRAWAL SYNDROME.
narcotics Drugs that produce insensitivity to
physical sensation, often altering perception and
the level of CONSCIOUSNESS. Many narcotics subject
to abuse are legitimate drugs that have therapeutic
uses such as to relieve PAIN, stop COUGH, and treat
DIARRHEA. Anesthesiologists use some narcotics to
initiate or provide ANESTHESIA. Some narcotics are
illicit, produced in clandestine labs by people who
have rudimentary knowledge of chemistry. All
narcotics have high risk for DEPENDENCE and
ADDICTION. Accordingly narcotics are SCHEDULED
DRUGS in the United States and many other
countries, restricting their legal use and posses-
sion.
Narcotics act on neuroreceptors in the CENTRAL
NERVOUS SYSTEM(BRAINand SPINAL CORD) called opi-
ate receptors, which researchers discovered in
- These specialized proteins regulate the
brain’s perceptions about and responses to pain
signals as well as certain aspects of mood and con-
sciousness. Opiate receptor binding also influences
the rate of BREATHING(respiratory rate). The gas-
trointestinal tract contains some opiate receptors,
which is why certain types of narcotics are useful
for treating diarrhea and others cause CONSTIPATION
as an undesired SIDE EFFECT.
There are two general classifications of nar-
cotics: OPIATES, which come from natural sources,
and synthetics, which are produced from chemi-
cals in laboratories. Opiates derive from opium,
the sap from the Papaver somniferumpoppy plant.
Synthetic narcotics, sometimes called opioids
because they act in an opiate-like manner in the
body, are chemical formulas designed in the labo-
ratory to bind with specific types of opiate recep-
tors for a lower risk of dependence and addiction.
Opiate receptors rapidly become tolerant to the
actions of narcotics, resulting in higher doses
being necessary to achieve the same effect.
Narcotics come in forms for all ROUTES OF ADMIN-
ISTRATION: oral (liquids, tablets, capsules), rectal
(suppositories), sublingual (under the tongue),
intravenous injection (with a needle into a VEIN),
intramuscular injection (with a needle into a MUS-
CLE), subcutaneous (with a needle under the SKIN),
transdermal (patches, for absorption through the
skin), and mucosal (sprays or lozenges, for absorp-
tion through the mucous membranes of the MOUTH
or NOSE). Some narcotics do not absorb well
through the gastrointestinal tract and are available
only for injection, whereas for other narcotics
injection offers the most rapid effect. The most
commonly used methods for abuse are oral and
injectable. As well, in circumstances of narcotic
abuse a person may add a powdered narcotic to a344