CNS Depressants Overview

CNS Depressants

• Also known as "downers" or "minor tranquilizers," or sedatives.
• Primarily based on sedative-hypnotic agents.
• Often prescribed by physicians.

CNS Depressants: Problematic Aspects

• Can cause alarming and dangerous behavior if not closely monitored.
• Primarily due to inadequate professional supervision.
• Seemingly unrelated drugs can cause CNS depression.
• Interactions among drug combinations can be dangerous.
• Can induce disruptive personality changes.

History of CNS Depressants

• Attempts to find alternatives to alcohol as CNS depressants started in the 1800s.
• Bromides were introduced in the 1800s to treat anxiety and nervousness; however, they were toxic.
• Barbiturates replaced bromides in the early 1900s, initially hailed as safe but later revealed issues with tolerance, dependence, and safety concerns.
• Benzodiazepines emerged in the 1950s as substitutes for barbiturates.
• Benzodiazepines were widely prescribed for stress, anxiety, and apprehension.
• In 1973, 100 million prescriptions for benzodiazepines were written, with women more likely to take them than men.
• As awareness of the problem grew, the use of depressants declined.

Effects of CNS Depressants

• Reduce CNS activity and the brain's level of awareness.
• Include benzodiazepines, barbiturate-like drugs, alcohol, antihistamines, and opioid narcotics like heroin.

Classification of CNS Depressants

• Sedatives cause mild CNS depression and relaxation, and they reduce nervousness, excitability, and irritability without sleep.
• Anxiolytics relieve anxiety
• Hypnotics calm the CNS to the point of inducing sleep; drowsiness and sleep is often a side effect. Amnesic effects can cause memory loss
• Effects vary with dose: low doses (sedatives) relieve anxiety and promote relaxation; higher doses (hypnotics) cause drowsiness and promote sleep while even higher doses (anesthetics) cause anesthesia.

Dose-Response Curves

• Dose-response curves for hypothetical sedative-hypnotics, illustrating how the effects change with drug doses.

Safety of Benzodiazepines

• Benzodiazepines have a relatively safe therapeutic dose, with the lethal dose being significantly higher than the typical therapeutic dose.

How Benzodiazepines Work

• Affect neurons with GABA receptors.
• GABA is an inhibitory neurotransmitter.
• Impact various brain regions, including the limbic system (mood alteration), reticular activating system (drowsiness), and motor cortex (muscle relaxation).

Types of CNS Depressants

• Benzodiazepines (Valium-type drugs): Prescribed for anxiety and sleep, with medical uses including anxiety relief, neurosis treatment, muscle relaxation, lower back pain treatment, convulsive disorder treatment, sleep induction, withdrawals relief, and amnesia induction.

• Many benzodiazepines available; distinguished by duration of action (short-acting/hypnotics and long-acting/sedatives).

• Barbiturates: Once significant sedative-hypnotic agents; however, issues with a narrow therapeutic window and high abuse potential led to their replacement by benzodiazepines. Some side effects can be from nausea to death, resulting from respiratory or cardiovascular depression.

• Other types: Drugs with similar properties to barbiturates (e.g., chloral hydrate, glutethimide, methyprylon, methaqualone); antihistamines; GHB (gamma-hydroxybutyrate).

Patterns of Abuse with CNS Depressants

• Individuals using depressants to relieve stress may paradoxically experience euphoria and stimulation.
• They may use depressants to counteract other substances' unpleasant effects.

Detoxification Procedures

• Elimination of the toxic substance, achieved by substituting a longer-acting barbiturate and gradually reducing the dose for CNS depressants.

Patterns of CNS Depressant Abuse: DSM Criteria

• DSM-5 criteria for substance abuse: Patterns of use can lead to significant impairment or distress.
• Recurrent use causing failure to fulfill obligations at work, school, or home.
• Use in physically hazardous situations.
• Recurring legal problems due to recurrent substance use.
• Continued use despite persistent social or interpersonal issues.
• Symptoms do not meet the criteria for dependence in that class of substance.
• DSM-5 criteria for substance dependence: Patterns of problematic substance use.
• Substance use in larger amounts or over a longer period than intended.
• Persistent desire to control or cut down on use and unsuccessful efforts to do so.
• Significant time devoted to obtaining, using, or recovering from the drug's effects.
• Reduction in important social, occupational, or recreational activities.
• Continued use despite awareness of a persistent related physical or psychological problem.

Adverse Effects: Barbiturates

• Presence of pulmonary insufficiency can cause dangerous respiratory depression.
• Rapid IV injection can cause cardiovascular collapse.
• Worsen pain perception.
• Severe withdrawal syndromes are a concern.
• Can lead to fatal poisoning due to severe respiratory and central CV depression.

Adverse Effects: Alcohol

• Excessive consumption leads to decreased muscle control, poor coordination, double vision, flushing, bloodshot eyes, and vomiting.
• Chronic use is associated with liver cirrhosis.

Other Adverse Effects

• Behavioral changes in intoxicated individuals can range from crying to euphoria, stimulation, or passing out.
• Varying effects, depending on the dosage

Explore the characteristics, problematic aspects, and historical evolution of CNS depressants. This quiz covers their classification, effects, and the timeline of their development from bromides to benzodiazepines. Test your knowledge on these critical sedative-hypnotic agents and their implications.