CNS Depressants PDF

DEPRESSANTS Adapted from:  Introduction to CNS Depressants Also known as the ‘downers’ or ‘minor tranquilizers’ or sedative Depressants are usually based around the sedative-hypnotic agents Why are CNS depressants problematic? - Usually prescr...

DEPRESSANTS Adapted from:  Introduction to CNS Depressants Also known as the ‘downers’ or ‘minor tranquilizers’ or sedative Depressants are usually based around the sedative-hypnotic agents Why are CNS depressants problematic? - Usually prescribed under physician direction  Introduction to CNS Depressants (continued) Why are CNS depressants problematic? - Can cause very alarming and dangerous behavior if not closely monitored Most problems associated with these drugs Loading… due to inadequate professional supervision - Seemingly unrelated drug groups can cause CNS depression - Combination use can cause dangerous drug interactions - Can cause disruptive personality changes  The History of CNS Depressants Attempts to find CNS depressants other than alcohol began in the 1800s. Bromides were introduced to treat nervousness and anxiety in the 1800s. - Very popular but toxic. In the early 1900s, bromides were replaced by barbiturates. - Initially heralded as safe and effective. - Problems with tolerance, dependence, and safety became apparent.  The History of CNS Depressants (continued) In the 1950s the first benzodiazepines were marketed as substitutes for barbiturates. - - Loading… Relatively safe when used for short periods Long-term use can cause dependence and withdrawal problems  The History of CNS Depressants (continued) Benzodiazepines were routinely prescribed for stress, anxiety, or apprehension. - In 1973 100 million prescriptions were written for benzodiazepines. - Twice as many women as men taking them. - “Mother’s Little Helper” by the Rolling Stones. As medical community became aware of the problem, use of depressants declined.  The Effects of CNS Depressants CNS depressants reduce CNS activity and diminish the brain’s level of awareness. Depressant drugs include: - Benzodiazepines - Barbiturate-like drugs - Alcohol - Antihistamines - Opioid narcotics like heroin  Depressants are usually classified according to the degree of their medical effects on the body. For example: Sedatives cause mild CNS depression and relaxation. Sedatives are drugs that have an inhibitory effect on the CNS to the degree that they reduce: - Nervousness - Excitability - Irritability - without causing sleep Anxiolytic—drugs that relieve anxiety  The Effects of CNS Depressants (continued) Hypnotics calm or soothe the CNS to the point that they cause sleep - induce drowsiness and encourage sleep Amnesic effects can cause the loss of memory  The Effects of CNS Depressants (continued) The same drug can cause different effects based on dose (dose-dependent) - Low dose (sedatives—relieve anxiety and promote relaxation) - Higher doses (hypnotics—can cause drowsiness and promote sleep) - Even higher doses (anesthetics—can cause anesthesia and are used for patient management during surgery)  Dose-response curves for two hypothetical sedative-hypnotics Coma DRUG A Anaesthesia Loading… DRUG B Hypnosis Sedation Increasing dose  How do they work? Mechanisms of action for benzodiazepine - Affect neurons that have receptors for the neurotransmitter GABA GABA—inhibitory transmitter in brain regions - Limbic system (alter mood) - RAS (cause drowsiness) - Motor cortex (relax muscles)  Types of CNS Depressants Benzodiazepines: Valium-Type Drugs - Prescribed for anxiety and sleep Medical uses - 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, induction of amnesia  Types of CNS Depressants (continued) Types of benzodiazepines - Many benzodiazepine compounds available in the U.S. - Distinguished primarily by their duration of action: short-acting (hypnotics), long-acting (sedatives)  Types of CNS Depressants (continued) Barbiturates played an important role as sedative-hypnotic agents. However, due to their narrow margin of safety and their abuse liability, they were replaced by benzodiazepines. - Caused many negative side effects, from nausea to death, from respiratory or cardiovascular depression  Types of CNS Depressants (continued) Alcohol is the oldest and most widely used drug in the world Small, regular amounts of alcohol also seem to have a positive effect on the heart and circulation As alcohol levels increase with more drinking, there is poor control of muscles, poor coordination, double vision, flushing of the face, bloodshot eyes, and vomiting  Types of CNS Depressants (continued) Behavior varies greatly-hard to predict what an intoxicated person will do next ranging from cry bitterly, show unexplained happiness, change moods rapidly, or just pass out Chronic use of alcohol causes liver cirrhosis  Other Types of CNS Depressants Drugs with barbiturate-like properties - Chloral hydrate - Glutethimide - Methyprylon - Methaqualone Antihistamines GHB (gamma hydroxybutyrate)  Patterns of Abuse with CNS Depressants The American Psychiatric Association considers dependence on CNS depressants a psychiatric disorder.  Substance Abuse by DSM Criteria A maladaptive pattern of substance use leading to clinically significant impairment or distress One (or more) of the following, within a 12-month period: (1) Recurrent substance use resulting in failure to fulfill major role obligations at work, school, or home (2) Recurrent substance use in situations in which it is physically hazardous (3) Recurrent substance-related legal problems (4) Continued substance use despite having persistent or recurrent social or interpersonal problems caused or exacerbated by the effects of the substance Symptoms have never met the criteria for substance dependence for this class of substance  Substance Dependence by DSM criteria A maladaptive pattern of substance use leading to clinically significant impairment or distress Three (or more) of the following, occurring in same 12-month period: Tolerance Withdrawal 3. The substance is taken in larger amounts or over a longer period than was intended 4. Persistent desire or unsuccessful efforts to cut down or control substance use 5. A great deal of time is spent on activities necessary to obtain the substance, use the substance, or recover from its effects 6. Important social, occupational, or recreational activities are given up or reduced 7. The substance use is continued despite knowledge of having a persistent physical or psychological problem likely to have been caused or exacerbated by the substance  Patterns of Abuse with CNS Depressants (continued) People most likely to abuse CNS depressants include individuals who - Use drugs to relieve continual stress - Paradoxically feel euphoria and stimulation from depressants - Use depressants to counteract the unpleasant effects of other drugs of abuse - Combine depressants with alcohol and heroin to potentiate the effects  Patterns of Abuse with CNS Depressants (continued) Detoxification—the elimination of a toxic substance, such as a drug, and its effects - With CNS depressants, this is achieved by substituting a longer-acting barbiturate for the offending CNS depressant and gradually reducing the dose.