How
is cocaine used?
The
principal routes of cocaine administration are oral, intranasal,
intravenous, and inhalation. The slang terms for these routes
are, respectively, "chewing," "snorting," "mainlining," "injecting,"
and "smoking" (including freebase and crack cocaine). Snorting
is the process of inhaling cocaine powder through the nostrils,
where it is absorbed into the bloodstream through the nasal tissues.
Injecting releases the drug directly into the bloodstream, and
heightens the intensity of its effects. Smoking involves the inhalation
of cocaine vapor or smoke into the lungs, where absorption into
the bloodstream is as rapid as by injection. The drug can also
be rubbed onto mucous tissues. Some users combine cocaine powder
or crack with heroin in a "speedball."
Cocaine
use ranges from occasional use to repeated or compulsive use,
with a variety of patterns between these extremes. There is no
safe way to use cocaine. Any route of administration can lead
to absorption of toxic amounts of cocaine, leading to acute cardiovascular
or cerebrovascular emergencies that could result in sudden death.
Repeated cocaine use by any route of administration can produce
addiction and other adverse health consequences.
How
does cocaine produce its effects?
A
great amount of research has been devoted to understanding the
way cocaine produces its pleasurable effects, and the reasons
it is so addictive. One mechanism is through its effects on structures
deep in the brain. Scientists have discovered regions within the
brain that, when stimulated, produce feelings of pleasure. One
neural system that appears to be most affected by cocaine originates
in a region, located deep within the brain, called the ventral
tegmental area (VTA). Nerve cells originating in the VTA extend
to the region of the brain known as the nucleus accumbens, one
of the brain's key pleasure centers. In studies using animals,
for example, all types of pleasurable stimuli, such as food, water,
sex, and many drugs of abuse, cause increased activity in the
nucleus accumbens.
Cocaine
in the brain - In the normal communication process, dopamine is
released by a neuron into the synapse, where it can bind with
dopamine receptors on neighboring neurons. Normally dopamine is
then recycled back into the transmitting neuron by a specialized
protein called the dopamine transporter. If cocaine is present,
it attaches to the dopamine transporter and blocks the normal
recycling process, resulting in a buildup of dopamine in the synapse
which contributes to the pleasurable effects of cocaine.

Researchers
have discovered that, when a pleasurable event is occurring, it
is accompanied by a large increase in the amounts of dopamine
released in the nucleus accumbens by neurons originating in the
VTA. In the normal communication process, dopamine is released
by a neuron into the synapse (the small gap between two neurons),
where it binds with specialized proteins (called dopamine receptors)
on the neighboring neuron, thereby sending a signal to that neuron.
Drugs of abuse are able to interfere with this normal communication
process. For example, scientists have discovered that cocaine
blocks the removal of dopamine from the synapse, resulting in
an accumulation of dopamine. This buildup of dopamine causes continuous
stimulation of receiving neurons, probably resulting in the euphoria
commonly reported by cocaine abusers.
As
cocaine abuse continues, tolerance often develops. This means
that higher doses and more frequent use of cocaine are required
for the brain to register the same level of pleasure experienced
during initial use. Recent studies have shown that, during periods
of abstinence from cocaine use, the memory of the euphoria associated
with cocaine use, or mere exposure to cues associated with drug
use, can trigger tremendous craving and relapse to drug use, even
after long periods of abstinence.
What
are the short-term effects of cocaine use?
Cocaine's
effects appear almost immediately after a single dose, and disappear
within a few minutes or hours. Taken in small amounts (up to 100
mg), cocaine usually makes the user feel euphoric, energetic,
talkative, and mentally alert, especially to the sensations of
sight, sound, and touch. It can also temporarily decrease the
need for food and sleep. Some users find that the drug helps them
to perform simple physical and intellectual tasks more quickly,
while others can experience the opposite effect. The duration
of cocaine's immediate euphoric effects depends upon the route
of administration. The faster the absorption, the more intense
the high. Also, the faster the absorption, the shorter the duration
of action. The high from snorting is relatively slow in onset,
and may last 15 to 30 minutes, while that from smoking may last
5 to 10 minutes. The short-term physiological effects of cocaine
include constricted blood vessels; dilated pupils; and increased
temperature, heart rate, and blood pressure. Large amounts (several
hundred milligrams or more) intensify the user's high, but may
also lead to bizarre, erratic, and violent behavior. These users
may experience tremors, vertigo, muscle twitches, paranoia, or,
with repeated doses, a toxic reaction closely resembling amphetamine
poisoning. Some users of cocaine report feelings of restlessness,
irritability, and anxiety. In rare instances, sudden death can
occur on the first use of cocaine or unexpectedly thereafter.
Cocaine-related deaths are often a result of cardiac arrest or
seizures followed by respiratory arrest
|
Short-term
effects of cocaine
|
| Increased
energy |
Decreased
appetite |
| Mental
alertness |
Constricted
blood vessels |
| Dilated
pupils |
Increased
temperature |
| Increased
heart rate and blood pressure |
