CNS Depressants Overview

CNS Depressants

• Also known as "downers," "minor tranquilizers," or sedatives
• Primarily based on sedative-hypnotic agents
• Commonly prescribed by physicians
• Can cause alarming and dangerous behaviors if not closely monitored
• Problems often stem from inadequate professional supervision
• Interactions with other drugs can be dangerous
• Can cause disruptive personality changes
• CNS depressants reduce central nervous system activity and awareness
• Examples of depressant drugs include benzodiazepines, barbiturate-like drugs, alcohol, antihistamines and opioid narcotics like heroin

History of CNS Depressants

• Attempts to develop CNS depressants (other than alcohol) began in the 1800s
• Bromides were initially used to treat nervousness and anxiety in the 1800s, but were later found to be toxic
• Barbiturates were introduced in the early 1900s, initially lauded for safety and effectiveness, but later problems with tolerance, dependence, and safety became apparent
• Benzodiazepines were developed in the 1950s as substitutes for barbiturates
• Benzodiazepines were relatively safe when used for short periods but long-term use can cause issues such as dependence and withdrawal
• Benzodiazepines were frequently prescribed for anxiety, stress and apprehension, reaching 100 million prescriptions in 1973—twice as many women as men
• As public health concerns emerged, the use of depressants declined

Effects of CNS Depressants

• Dose-dependent effects: low doses can act as sedatives (relieving anxiety and promoting relaxation), higher doses as hypnotics (inducing drowsiness and sleep), and even higher doses as anesthetics (used for patient management)
• CNS depressants lower awareness and CNS activity

Mechanisms of Action of Benzodiazepines

• Act on neurons that have receptors for the neurotransmitter GABA
• GABA is an inhibitory neurotransmitter in several brain regions
  • Alters mood in the limbic system
  • Causes drowsiness in the RAS (reticular activating system)
  • Relaxes muscles in the motor cortex

Types of CNS Depressants

• Benzodiazepines (Valium-type drugs): used for anxiety and sleep
  • Medical uses include relief from anxiety, treatment of neurosis, relaxation of muscles, alleviation of lower-back pain, treatment of convulsive disorders, induction of sleep, relief from withdrawal symptoms, and induction of amnesia
  • Many types with varying durations of action (short-acting and long-acting)
• Barbiturates:
  • Played an important role as sedative-hypnotic agents
  • Their narrow margin of safety and abuse liability led to their replacement by benzodiazepines
  • Caused serious side effects, from nausea to death, due to respiratory or cardiovascular depression

Other Types of CNS Depressants

• Drugs with barbiturate-like properties includes chloral hydrate, glutethimide, methyprylon, methaqualone
• Antihistamines
• GHB (gamma hydroxybutyrate)

Patterns of Abuse with CNS Depressants

• People prone to abuse CNS depressants often use them to relieve stress, paradoxically experiencing euphoria and stimulation which potentially counteracts the unpleasant effects of other drugs
• Mixing CNS depressants with alcohol or heroin potentiates their effects
• Detoxification involves eliminating the toxic substance (e.g. a drug) and its effects using a longer acting barbiturate to substitute the offending CNS depressant and gradually reduce the dose

Substance Abuse by DSM Criteria

• A pattern of substance use leading to clinically significant distress or impairment
• Criteria may include recurrent use, disregard of the substance's effects, recurrence of substance related legal issues, and using the substance despite negative outcomes
• Symptoms of substance use do not meet dependence criteria

Substance Dependence by DSM Criteria

• Symptoms include tolerance (requiring higher doses to achieve the same effect), dependence in withdrawal,taking more or longer than intended, unsuccessful efforts to control use, spending significant time on substance use or recovery, giving up or reducing important social/occupational/recreational activities, and using substance despite physical or psychological problems

Delve into the world of CNS depressants, including their history, usage, and potential dangers. This quiz covers the various types of sedative-hypnotic agents and their impact on the central nervous system. Understand the evolution of these drugs from the 1800s to the present.