What
are the immediate (short-term) effects of heroin use?
Soon
after injection (or inhalation), heroin crosses the blood-brain barrier.
In the brain, heroin is converted to morphine and binds rapidly to
opioid receptors. Abusers typically report feeling a surge of pleasurable
sensation, a "rush." The intensity of the rush is a function of how
much drug is taken and how rapidly the drug enters the brain and binds
to the natural opioid receptors. Heroin is particularly addictive
because it enters the brain so rapidly. With heroin, the rush is usually
accompanied by a warm flushing of the skin, dry mouth, and a heavy
feeling in the extremities, which may be accompanied by nausea, vomiting,
and severe itching.
After
the initial effects, abusers usually will be drowsy for several hours.
Mental function is clouded by heroin's effect on the central nervous
system. Cardiac function slows. Breathing is also severely slowed,
sometimes to the point of death. Heroin overdose is a particular risk
on the street, where the amount and purity of the drug cannot be accurately
known.
What
are the long-term effects of heroin use?
One of
the most detrimental long-term effects of heroin is addiction itself.
Addiction
is a chronic, relapsing disease, characterized by compulsive drug
seeking and use, and by neurochemical and molecular changes in the
brain. Heroin also produces profound degrees of tolerance and physical
dependence, which are also powerful motivating factors for compulsive
use and abuse. As with abusers of any addictive drug, heroin abusers
gradually spend more and more time and energy obtaining and using
the drug. Once they are addicted, the heroin abusers' primary purpose
in life becomes seeking and using drugs. The drugs literally change
their brains.
Physical
dependence develops with higher doses of the drug. With physical dependence,
the body adapts to the presence of the drug and withdrawal symptoms
occur if use is reduced abruptly. Withdrawal may occur within a few
hours after the last time the drug is taken. Symptoms of withdrawal
include restlessness, muscle and bone pain, insomnia, diarrhea, vomiting,
cold flashes with goose bumps ("cold turkey"), and leg movements.
Major withdrawal symptoms peak between 24 and 48 hours after the last
dose of heroin and subside after about a week. However, some people
have shown persistent withdrawal signs for many months. Heroin withdrawal
is never fatal to otherwise healthy adults, but it can cause death
to the fetus of a pregnant addict.
At some
point during continuous heroin use, a person can become addicted to
the drug. Sometimes addicted individuals will endure many of the withdrawal
symptoms to reduce their tolerance for the drug so that they can again
experience the rush.
Physical
dependence and the emergence of withdrawal symptoms were once believed
to be the key features of heroin addiction. We now know this may not
be the case entirely, since craving and relapse can occur weeks and
months after withdrawal symptoms are long gone. We also know that
patients with chronic pain who need opiates to function (sometimes
over extended periods) have few if any problems leaving opiates after
their pain is resolved by other means. This may be because the patient
in pain is simply seeking relief of pain and not the rush sought by
the addict.
References:
National Institutes On Drug Abuse (NIDA), U.S. Department of Health
and Human Services · National Institutes of Health