Cns depressants

1. Central Nervous System Central Nervous System
DepressantsDepressants

2. CNS Depressants CNS Depressants
SedativesSedatives
•Drugs that have an inhibitory effect on the Drugs 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

3. CNS Depressants CNS Depressants
HypnoticsHypnotics
•Calm or soothe the CNS to the point that they Calm or soothe the CNS to the point that they
cause sleepcause sleep

4. CNS DepressantsCNS Depressants
Sedative-Hypnotics—dose dependent:Sedative-Hypnotics—dose dependent:
•At low doses, calm or soothe the CNS At 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

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

6. Sedative-Hypnotics: BarbituratesSedative-Hypnotics: Barbiturates
Four categories:Four categories:
•UltrashortUltrashort
–mephobexital, thiamylal, thiopentalmephobexital, thiamylal, thiopental
•ShortShort
–pentobarbital, secobarbitalpentobarbital, secobarbital
•IntermediateIntermediate
–aprobarbital, butabarbitalaprobarbital, butabarbital
•LongLong
–phenobarbitalphenobarbital

7. Sedative-Hypnotics: BarbituratesSedative-Hypnotics: Barbiturates
Barbiturates have a very narrow therapeutic index.Barbiturates have a very narrow therapeutic index.
Therapeutic IndexTherapeutic Index
•Dosage range within which the drug is effective Dosage range within which the drug is effective
but above which is rapidly toxic.but above which is rapidly toxic.

8. Sedative-Hypnotics: BarbituratesSedative-Hypnotics: Barbiturates
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 in By inhibiting GABA, nerve impulses traveling in
the cerebral cortex are also inhibited.the cerebral cortex are also inhibited.

9. Sedative-Hypnotics: BarbituratesSedative-Hypnotics: Barbiturates
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

10. Sedative-Hypnotics: BarbituratesSedative-Hypnotics: Barbiturates
Therapeutic UsesTherapeutic Uses
•HypnoticsHypnotics
•SedativesSedatives
•AnticonvulsantsAnticonvulsants
•Surgical proceduresSurgical procedures

11. Sedative-Hypnotics: BarbituratesSedative-Hypnotics: Barbiturates
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

12. Sedative-Hypnotics: BarbituratesSedative-Hypnotics: Barbiturates
Side EffectsSide Effects
Body SystemBody System EffectsEffects
GIGI Nausea, vomiting, diarrheaNausea, vomiting, diarrhea
OtherOther Agranulocytosis, Agranulocytosis,
vasodilation, hypotension, vasodilation, hypotension,
Stevens-Johnson syndromeStevens-Johnson syndrome

13. Sedative-Hypnotics: BarbituratesSedative-Hypnotics: Barbiturates
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”

14. Sedative-Hypnotics: BarbituratesSedative-Hypnotics: Barbiturates
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 to Reduces anticoagulant response, leading to
possible clot formationpossible clot formation

15. 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

16. CNS Depressants: BenzodiazepinesCNS Depressants: Benzodiazepines
Classified as either:Classified as either:
•Sedative-hypnotic or AnxiolyticSedative-hypnotic or Anxiolytic
(Medication that relieves anxiety)(Medication that relieves anxiety)

17. CNS Depressants: BenzodiazepinesCNS Depressants: Benzodiazepines
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)

18. CNS Depressants: BenzodiazepinesCNS Depressants: Benzodiazepines
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)

19. CNS Depressants: BenzodiazepinesCNS Depressants: Benzodiazepines
Mechanism of ActionMechanism of Action
•Depress CNS activityDepress CNS activity
•Affect hypothalamic, thalamic, and limbic Affect hypothalamic, thalamic, and limbic
systems of the brainsystems of the brain
•Benzodiazepine receptorsBenzodiazepine receptors

20. CNS Depressants: BenzodiazepinesCNS Depressants: Benzodiazepines
Drug EffectsDrug Effects
•Calming effect on the CNSCalming effect on the CNS
•Useful in controlling agitation and anxietyUseful in controlling agitation and anxiety

21. CNS Depressants: BenzodiazepinesCNS Depressants: Benzodiazepines
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

22. CNS Depressants: BenzodiazepinesCNS Depressants: Benzodiazepines
Side EffectsSide Effects
•Mild and infrequentMild and infrequent
HeadacheHeadache DrowsinessDrowsiness
DizzinessDizziness VertigoVertigo
LethargyLethargy
Paradoxical excitement (nervousness) Paradoxical excitement (nervousness)
“Hangover effect”“Hangover effect”

23. CNS Depressants: CNS Depressants:
Nursing ImplicationsNursing Implications
•Before beginning therapy, perform a Before beginning therapy, perform a
thorough history regarding allergies, use thorough history regarding allergies, use
of other medications,health history, and of 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 conditions Assess for potential disorders or conditions
that may be contraindications, and for that may be contraindications, and for
potential drug interactions.potential drug interactions.

24. CNS Depressants: CNS Depressants:
Nursing ImplicationsNursing Implications
•Give 15 to 30 minutes before bedtime for Give 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 the cause 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 avoid Patients should be instructed to avoid
alcohol and other CNS depressants.alcohol and other CNS depressants.

25. CNS Depressants: CNS Depressants:
Nursing ImplicationsNursing Implications
•Check with physician before taking any other Check with physician before taking any other
medications, including OTC medications.medications, including OTC medications.
•It may take 2 to 3 weeks to notice improved It 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 rebound especially barbiturates, may cause rebound
insomnia.insomnia.

26. CNS Depressants: CNS Depressants:
Nursing ImplicationsNursing Implications
•Safety is importantSafety is important
–Keep side rails upKeep side rails up
–Do not permit smokingDo not permit smoking
–Assist patient with ambulation Assist 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

27. CNS Depressants: CNS Depressants:
Nursing ImplicationsNursing Implications
•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 of Improved sense of well-being because of
improved sleepimproved sleep