CNS depressants (e.g., tranquilizers, sedatives) are medications that slow normal brain function. In higher doses, some CNS depressants can be used as general anesthetics or pre-anesthetics.
CNS depressants can be divided into three groups, based on their chemistry and pharmacology:
Barbiturates, such as mephobarbital (Mebaral) and sodium pentobarbital (Nembutal), are used as pre-anesthetics, promoting sleep.
Benzodiazepines, such as diazepam (Valium), alprazolam (Xanax), and estazolam (ProSom), can be prescribed to treat anxiety, acute stress reactions, panic attacks, convulsions, and sleep disorders. For the latter, benzodiazepines are usually prescribed only for short-term relief of sleep problems because of the development of tolerance and risk of addiction.
Newer sleep medications, such as zolpidem (Ambien), zaleplon (Sonata), and eszopiclone (Lunesta), are now more commonly prescribed to treat sleep disorders. These medications are nonbenzodiazepines that act at a subset of the benzodiazepine receptors and appear to have a lower risk for abuse and addiction.
How Are CNS Depressants Abused?
CNS depressants are usually taken orally, sometimes in combination with other drugs or to counteract the effects of other licit or illicit drugs (e.g., stimulants).
How Do CNS Depressants Affect the Brain?
Most of the CNS depressants have similar actions in the brain: they enhance the actions of the neurotransmitter gamma-aminobutyric acid (GABA)—neurotransmitters are brain chemicals that facilitate communication between brain cells. GABA works by decreasing brain activity. Although different classes of CNS depressants work in unique ways, it is ultimately their common ability to increase GABA activity that produces a drowsy or calming effect.
What Adverse Effects Can Be Associated With CNS Depressants?
Despite their beneficial effects for people suffering from anxiety or sleep disorders, barbiturates and benzodiazepines can be addictive and should be used only as prescribed.
CNS depressants should not be combined with any medication or substance that causes drowsiness, including prescription pain medicines, certain OTC cold and allergy medications, and alcohol. If combined, they can slow both heart rate and respiration, which can be fatal.
What Happens When You Stop Taking CNS Depressants?
Discontinuing prolonged use or abuse of high doses of CNS depressants can lead to serious withdrawal symptoms. Because the drug works by slowing the brain’s activity, when one stops taking a CNS depressant, this activity can rebound to the point that seizures can occur. Someone who is either thinking about ending use of a CNS depressant, or who has stopped and is suffering withdrawal should seek medical treatment.
Are There Treatments for Addiction to CNS Depressants?
In addition to medical supervision during withdrawal, counseling in an inpatient or outpatient setting can help people who are overcoming addiction to CNS depressants. For example, cognitive-behavioral therapy has been used successfully to help individuals in treatment for abuse of benzodiazepines. This type of therapy focuses on modifying a patient’s thinking, expectations, and behaviors while simultaneously increasing his or her skills for coping with various life stressors.