CNS Depressants: Sedative-Hypnotics Chapter 6. Why are CNS depressants problematic? Usually prescribed under physician direction Second most frequently
Why are CNS depressants problematic? Usually prescribed under
physician direction Second most frequently abused prescription drug
and sometimes contributes to death due to accidental overdoses Can
cause very alarming and dangerous behavior if not closely monitored
Most problems associated with these drugs due to inadequate
professional supervision
Slide 3
Slide 4
In your small group, discuss why you think physicians may be
careless when prescribing depressants for patients suffering from
anxiety. Discuss what you believe are the dangers of this practice
and what other alternate therapies may exist
Slide 5
Why are CNS depressants problematic? Seemingly unrelated drug
groups can cause CNS depression (see case in point, p.162)
Combination use can cause dangerous drug interactions Can cause
disruptive personality changes
Slide 6
Attempts to find CNS depressants other than alcohol began in
the 1800s. Bromides were introduced to treat nervousness and
anxiety in the 1800s. Bromides Very popular but toxic In the early
1900s, bromides were replaced by barbiturates. barbiturates
Initially heralded as safe and effective Apparent problems with
tolerance, dependence, and safety
Slide 7
In the 1950s the first benzodiazepines were marketed as
substitutes for barbiturates.benzodiazepines Relatively safe when
used for short periods Long-term use can cause dependence and
withdrawal problems Article The history of barbiturates a century
after their clinical introductionThe history of barbiturates a
century after their clinical introduction
Slide 8
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. As
medical community became aware of the problem, use of depressants
declined, but benzodiazepines remained still very popular.
Classified as Schedule V drugs.
Slide 9
CNS depressants reduce CNS activity and diminish the brains
level of awareness. Depressant drugs include: Benzodiazepines
Barbiturate-like drugs Alcohol Antihistamines Opioid narcotics like
heroin
Slide 10
Depressants are usually classified according to the degree of
their medical effects on the body. For example: Sedatives cause
mild depression and relaxation, treat fear, apprehension
Anxiolyticdrugs that relieve anxiety Hypnotics induce drowsiness
and encourage sleep Amnesiac effects can cause the loss of
memory
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The same drug can cause different effects based on dose. Low
dose (sedativesrelieve anxiety and promote relaxation) Higher doses
(hypnoticscan cause drowsiness and promote sleep) Even higher doses
(anestheticscan cause anesthesia and are used for patient
management during surgery)
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Benzodiazepines: Valium-Type Drugs Prescribed for anxiety,
relaxation 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
Slide 15
Mechanisms of action for benzodiazepine Affect neurons that
have receptors for the neurotransmitter GABA GABAmost common
inhibitory transmitter in brain regions GABA Limbic system (alter
mood) RAS (cause drowsiness) Motor cortex (relax muscles)
Slide 16
Types of benzodiazepines Many benzodiazepine compounds
available in the United States Distinguished primarily by their
duration of action: short-acting (hypnotics), long- acting
(sedatives) See Table 6-1 for Half lives of various
benzodiazepines- next slide Side effects include drowsiness to
paradoxical effects (e.g. increased restlessness), tolerance,
dependence, withdrawal, and abuse
Slide 17
Slide 18
Barbiturates played an important historical 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 Discussion on
Whitney Houston and Michael JacksonWhitney Houston Michael
Jackson
Slide 19
Drugs with barbiturate-like properties: Chloral hydrate
Glutethimide Methyprylon Methaqualone Antihistamines Propofol
(abused general anesthetic) Propofol GHB (gamma hydroxybutyrate)
GHB
Slide 20
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
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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 to avoid unpleasant
withdrawal effects. Withdrawal from CNS depressants, if not managed
properly, can be very dangerous, or even fatal The American
Psychiatric Association considers dependence on CNS depressants a
psychiatric disorder.