cns depressants

Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved.
Central Nervous SystemCentral Nervous System
DepressantsDepressants

CNS DepressantsCNS Depressants
SedativesSedatives
• Drugs that have an inhibitory effect on theDrugs that have an inhibitory effect on the
CNS to the degree that they reduce:CNS to the degree that they reduce:
– NervousnessNervousness
– ExcitabilityExcitability
– IrritabilityIrritability
– without causing sleepwithout causing sleep

HypnoticsHypnotics
• Calm or soothe the CNS to the point that theyCalm or soothe the CNS to the point that they
cause sleepcause sleep

Sedative-Hypnotics—dose dependent:Sedative-Hypnotics—dose dependent:
• At low doses, calm or soothe the CNSAt low doses, calm or soothe the CNS
without inducing sleepwithout inducing sleep
• At high doses, calm or soothe the CNSAt high doses, calm or soothe the CNS
• to the point of causing sleepto the point of causing sleep

Sedative-Hypnotics: BarbituratesSedative-Hypnotics: Barbiturates
• First introduced in 1903, standard agentsFirst introduced in 1903, standard agents
for insomnia and sedationfor insomnia and sedation
• Habit-formingHabit-forming
• Only a handful commonly used today dueOnly a handful commonly used today due
in part to the safety and efficacy of:in part to the safety and efficacy of:
BENZODIAZEPINESBENZODIAZEPINES

Four categories:Four categories:
• UltrashortUltrashort
– mephobexital, thiamylal, thiopentalmephobexital, thiamylal, thiopental
• ShortShort
– pentobarbital, secobarbitalpentobarbital, secobarbital
• IntermediateIntermediate
– aprobarbital, butabarbitalaprobarbital, butabarbital
• LongLong
– phenobarbitalphenobarbital

Barbiturates have a very narrow therapeutic index.Barbiturates have a very narrow therapeutic index.
Therapeutic IndexTherapeutic Index
• Dosage range within which the drug is effectiveDosage range within which the drug is effective
but above which is rapidly toxic.but above which is rapidly toxic.

Mechanism of ActionMechanism of Action
• Site of action:Site of action:
– Brain stem (reticular formation)Brain stem (reticular formation)
– Cerebral cortexCerebral cortex
• By inhibiting GABA, nerve impulses traveling inBy inhibiting GABA, nerve impulses traveling in
the cerebral cortex are also inhibited.the cerebral cortex are also inhibited.

Drug EffectsDrug Effects
• Low doses:Low doses: Sedative effectsSedative effects
• High doses:High doses: Hypnotic effectsHypnotic effects
(also lowers respiratory rate)(also lowers respiratory rate)
Notorious enzyme inducersNotorious enzyme inducers

Therapeutic UsesTherapeutic Uses
• HypnoticsHypnotics
• SedativesSedatives
• AnticonvulsantsAnticonvulsants
• Surgical proceduresSurgical procedures

Side EffectsSide Effects
Body SystemBody System EffectsEffects
CNSCNS Drowsiness, lethargy, vertigoDrowsiness, lethargy, vertigo
mental depression, comamental depression, coma
RespiratoryRespiratory Respiratory depression, apnea,Respiratory depression, apnea,
bronchospasms, coughbronchospasms, cough

Body SystemBody System EffectsEffects
GIGI Nausea, vomiting, diarrheaNausea, vomiting, diarrhea
OtherOther Agranulocytosis,Agranulocytosis,
vasodilation, hypotension,vasodilation, hypotension,
Stevens-Johnson syndromeStevens-Johnson syndrome

ToxicologyToxicology
• Overdose frequently leads to respiratory depression,Overdose frequently leads to respiratory depression,
and subsequently, respiratory arrest.and subsequently, respiratory arrest.
• Can be therapeutic:Can be therapeutic:
– Anesthesia inductionAnesthesia induction
– Uncontrollable seizures: “phenobarbital coma”Uncontrollable seizures: “phenobarbital coma”

Drug InteractionsDrug Interactions
• Additive effects:Additive effects:
– ETOH, antihistamines, benzodiazepines,ETOH, antihistamines, benzodiazepines,
narcotics, tranquilizersnarcotics, tranquilizers
• Inhibited metabolism:Inhibited metabolism:
– MAOIs will prolong effects of barbituratesMAOIs will prolong effects of barbiturates
• Increased metabolism:Increased metabolism:
– Reduces anticoagulant response, leading toReduces anticoagulant response, leading to
possible clot formationpossible clot formation

CNS Depressants: BenzodiazepinesCNS Depressants: Benzodiazepines
Most frequently prescribed sedative-hypnoticsMost frequently prescribed sedative-hypnotics
• Most commonly prescribed drug classesMost commonly prescribed drug classes
• Favorable side effectsFavorable side effects
• EfficacyEfficacy
• SafetySafety

Classified as either:Classified as either:
• Sedative-hypnotic or AnxiolyticSedative-hypnotic or Anxiolytic
(Medication that relieves anxiety)(Medication that relieves anxiety)

Sedative-Hypnotic TypeSedative-Hypnotic Type
• Long-Acting:Long-Acting:
– flurazepam (Dalmane), quazepam (Doral)flurazepam (Dalmane), quazepam (Doral)
• Short-Acting:Short-Acting:
– estazolam (Prosom), temazepam (Restoril),estazolam (Prosom), temazepam (Restoril),
– triazolam (Halcion)triazolam (Halcion)

Anxiolytic TypeAnxiolytic Type
• alprazolam (Xanax)alprazolam (Xanax)
• chloridiazepoxide (Librium)chloridiazepoxide (Librium)
• diazepam (Valium)diazepam (Valium)
• lorazepam (Ativan)lorazepam (Ativan)
• midazolam (Versed)midazolam (Versed)
zolpidem (Ambien) and zaleplon (Sonata)zolpidem (Ambien) and zaleplon (Sonata)
(nonbenzodiazepine hypnotic agents, share characteristics)(nonbenzodiazepine hypnotic agents, share characteristics)

Mechanism of ActionMechanism of Action
• Depress CNS activityDepress CNS activity
• Affect hypothalamic, thalamic, and limbicAffect hypothalamic, thalamic, and limbic
systems of the brainsystems of the brain
• Benzodiazepine receptorsBenzodiazepine receptors

Drug EffectsDrug Effects
• Calming effect on the CNSCalming effect on the CNS
• Useful in controlling agitation and anxietyUseful in controlling agitation and anxiety

Therapeutic UsesTherapeutic Uses
• SedationSedation
• Sleep inductionSleep induction
• Skeletal muscle relaxationSkeletal muscle relaxation
• Anxiety reliefAnxiety relief
• Treatment of alcohol withdrawalTreatment of alcohol withdrawal
• AgitationAgitation
• DepressionDepression
• EpilepsyEpilepsy
• Balanced anesthesiaBalanced anesthesia

• Mild and infrequentMild and infrequent
HeadacheHeadache DrowsinessDrowsiness
DizzinessDizziness VertigoVertigo
LethargyLethargy
Paradoxical excitement (nervousness)Paradoxical excitement (nervousness)
“Hangover effect”“Hangover effect”

CNS Depressants:CNS Depressants:
Nursing ImplicationsNursing Implications
• Before beginning therapy, perform aBefore beginning therapy, perform a
thorough history regarding allergies, usethorough history regarding allergies, use
of other medications,health history, andof other medications,health history, and
medical history.medical history.
• Obtain baseline vital signs and I & O,Obtain baseline vital signs and I & O,
including supine and erect BPs.including supine and erect BPs.
• Assess for potential disorders or conditionsAssess for potential disorders or conditions
that may be contraindications, and forthat may be contraindications, and for
potential drug interactions.potential drug interactions.

• Give 15 to 30 minutes before bedtime forGive 15 to 30 minutes before bedtime for
maximum effectiveness in inducing sleep.maximum effectiveness in inducing sleep.
• Most benzodiazepines (except flurazepam)Most benzodiazepines (except flurazepam)
cause REM rebound and a tired feeling thecause REM rebound and a tired feeling the
next day; use with caution in the elderly.next day; use with caution in the elderly.
• Patients should be instructed to avoidPatients should be instructed to avoid
alcohol and other CNS depressants.alcohol and other CNS depressants.

• Check with physician before taking any otherCheck with physician before taking any other
medications, including OTC medications.medications, including OTC medications.
• It may take 2 to 3 weeks to notice improvedIt may take 2 to 3 weeks to notice improved
sleep when taking barbiturates.sleep when taking barbiturates.
• Abruptly stopping these medications,Abruptly stopping these medications,
especially barbiturates, may cause reboundespecially barbiturates, may cause rebound
insomnia.insomnia.

• Safety is importantSafety is important
– Keep side rails upKeep side rails up
– Do not permit smokingDo not permit smoking
– Assist patient with ambulationAssist patient with ambulation
(especially the elderly)(especially the elderly)
– Keep call light within reachKeep call light within reach
• Monitor for side effectsMonitor for side effects

• Monitor for therapeutic effectsMonitor for therapeutic effects
– Increased ability to sleep at nightIncreased ability to sleep at night
– Fewer awakeningsFewer awakenings
– Shorter sleep induction timeShorter sleep induction time
– Few side effects, such as hangover effectsFew side effects, such as hangover effects
– Improved sense of well-being because ofImproved sense of well-being because of
improved sleepimproved sleep

cns depressants

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to cns depressants

Similar to cns depressants (20)

More from DENNIS MUÑOZ

More from DENNIS MUÑOZ (20)

Recently uploaded

Recently uploaded (20)

cns depressants