How Do CNS Depressants Work? Uses, Side Effects, Drug Names

For the last section of our chapter on depressants, we will cover a type of drug that many people might overlook. Inhalants are solvents or other materials that produce vapors that elicit psychoactive effects. While a wide variety of products can be used as inhalants, most induce CNS depression through similar mechanisms of action. Barbiturates are positive allosteric modulators of GABAA receptors. By binding to areas other than the orthosteric site of the receptor, they enhance GABA activity. In particular, they increase the amount of time that the chloride ion channel remains open when GABA binds to the receptor.

Risk factors and predictors of depression after spinal cord injury: Emphasis on the inflammatory process

People should take depressants if they have been advised to do so by their healthcare provider. These medications can be safe when taken as prescribed, when not combined with alcohol or other drugs, and when not used while driving or operating heavy machinery. This is because long-term use—which is more common in older adults—can lead to tolerance, dependence, and withdrawal symptoms upon cessation. Benzodiazepines, also known as Benzos, are also used to treat anxiety and sleep disorders, although they are considered less addictive than barbiturates.

However, specific symptoms of intoxication and withdrawal are modulated by multiple neurotransmitter systems acting within different brain structures. For example, increased inhibition in the Papez circuit of the limbic system and basolateral amygdala may be responsible for the anxiolytic response during drug use and subsequent anxiogenic response during withdrawal. Barbiturates are believed to have a particularly strong effect on the mesencephalic reticular activating system. If synapses are activated postsynaptically by barbiturates, their receptors may be found on neurons in the cuneate nucleus, substantia nigra, and thalamus. The most prominent neurotransmitter systems activated during CNS depressant use are GABA and glutamate.

Chapter 10: CNS Depressants

However, the abuse of barbiturates continues to occur with street use as a “downer” to counteract the effect of cocaine and methamphetamine. The misuse of CNS depressants often stems from a variety of social, psychological, and physiological factors. Many individuals initially use these substances to self-medicate for conditions such as anxiety, insomnia, or chronic pain, seeking relief from uncomfortable symptoms. However, this can lead to a cycle of dependency as tolerance builds, prompting users to consume higher central nervous system (cns) depressants doses to achieve the desired effects.

WHAT ARE SIDE EFFECTS OF CNS DEPRESSANTS?

Chronic exposure to nitrous oxide inactivates Vitamin B12, a cofactor in the methylation pathway for DNA and protein synthesis. Clinically, this can be manifested as megaloblastic anemia, a condition caused by improper production of erythrocytes (red blood cells). As indicated by the name, inhalants are administered by inhaling the substance over some time at high concentrations.

Side effects and risks

1. It may also be used in adult patients for preanesthetic medication to produce sedation (sleepiness or drowsiness), relieve anxiety, and decrease the ability to recall events related to the day of surgery.
2. A minority of patients react to benzodiazepines with paradoxical agitation.
3. Obstetric anesthesiologists may also give sedatives to people experiencing distress or restlessness during labor.
4. High doses of a δ-opioid agonist can cause seizures, although not all delta agonists produce this effect.144 Activation of the delta receptor is usually stimulating instead of sedating like most opioids.

When GHB and alcohol are combined, the sedative and depressant effects are amplified, and GHB may reduce the rate at which alcohol is eliminated from the system. This synergistic interaction can lead to unexpected respiratory failure and death. Because they are weak acids, barbiturates are readily absorbed after oral administration. Ultrashort-acting barbiturates are usually administered by IV, while long-acting anticonvulsant medications may also be taken by suppository.

In small doses, these drugs slow brain function, producing a calm or sleepy feeling. The danger is when the CNS is slowed too much, which can lead to unconsciousness, coma, and death. These include Naloxone for opioid overdoses and Flumazenil for overdoses of benzodiazepine. An overdose of a CNS depressant can happen by accident, but people sometimes choose to take more of the drug than a doctor recommends to get a more “intense” effect. People have also been known to overdose on these medications deliberately to end their lives. Sometimes, a person may not realize they are at risk of an overdose, such as when they use opioid pain relief medication and then drink alcohol.

These are strong pain-relieving drugs that come from opium, a substance made from the seeds of the poppy. Also, the individual may need more and more of the drug to experience the same benefits. Some people may need rehabilitation therapy to stop using the drugs. If plasma concentrations rise further, generalized CNS depression, with unconsciousness and respiratory arrest, ensues.