CNS depressants
What are CNS depressants?
CNS depressants are substances
that can slow normal brain function. Because of this property, some
CNS depressants are useful in the treatment of anxiety and sleep disorders.
Among the medications that are commonly prescribed for these purposes
are the following:
- Barbiturates, such as mephobarbital (Mebaral) and pentobarbital
sodium (Nembutal), which are used to treat anxiety, tension, and
sleep disorders.
- Benzodiazepines, such as diazepam (Valium), chlordiazepoxide HCl
(Librium), and alprazolam (Xanax), which can be prescribed to treat
anxiety, acute stress reactions, and panic attacks; the more sedating
benzodiazepines, such as triazolam (Halcion) and estazolam (ProSom)
can be prescribed for short-term treatment of sleep disorders.
In higher doses, some CNS depressants can be used as general anesthetics.
How do CNS depressants
affect the brain and body?
There are numerous CNS depressants;
most act on the brain by affecting the neurotransmitter gamma-aminobutyric
acid (GABA). Neurotransmitters are brain chemicals that facilitate
communication between brain cells. GABA works by decreasing brain
activity. Although the different classes of CNS depressants work in
unique ways, ultimately it is through their ability to increase GABA
activity that they produce a drowsy or calming effect that is beneficial
to those suffering from anxiety or sleep disorders.
What are the possible consequences
of CNS depressant use and abuse?
Despite their many beneficial effects,
barbiturates and benzodiazepines have the potential for abuse and
should be used only as prescribed. During the first few days of taking
a prescribed CNS depressant, a person usually feels sleepy and uncoordinated,
but as the body becomes accustomed to the effects of the drug, these
feelings begin to disappear. If one uses these drugs long term, the
body will develop tolerance for the drugs, and larger doses will be
needed to achieve the same initial effects. In addition, continued
use can lead to physical dependence and - when use is reduced or stopped
- withdrawal. Because all CNS depressants work by slowing the brain's
activity, when an individual stops taking them, the brain's activity
can rebound and race out of control, possibly leading to seizures
and other harmful consequences. Although withdrawal from benzodiazepines
can be problematic, it is rarely life threatening, whereas withdrawal
from prolonged use of other CNS depressants can have life-threatening
complications. Therefore, someone who is thinking about discontinuing
CNS depressant therapy or who is suffering withdrawal from a CNS depressant
should speak with a physician or seek medical treatment.
Is it safe to use CNS depressants
with other medications?
CNS depressants should be used
with other medications only under a physician's supervision. Typically,
they should not be combined with any other medication or substance
that causes CNS depression, including prescription pain medicines,
some over-the-counter cold and allergy medications, or alcohol. Using
CNS depressants with these other substances - particularly alcohol
- can slow breathing, or slow both the heart and respiration, and
possibly lead to death.
