Central Nervous System Depressants

CNS Depressants Sedatives Drugs that have an inhibitory effect on the CNS to the degree that they reduce: Nervousness Excitability Irritability without causing sleep

Sedatives

Drugs that have an inhibitory effect on the CNS to the degree that they reduce:

Nervousness

Excitability

Irritability

without causing sleep

CNS Depressants Hypnotics Calm or soothe the CNS to the point that they cause sleep

Hypnotics

Calm or soothe the CNS to the point that they cause sleep

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

Sedative-Hypnotics—dose dependent:

At low doses, calm or soothe the CNS without inducing sleep

At high doses, calm or soothe the CNS

to the point of causing sleep

Sedative-Hypnotics: Barbiturates First introduced in 1903, standard agents for insomnia and sedation Habit-forming Only a handful commonly used today due in part to the safety and efficacy of: BENZODIAZEPINES

First introduced in 1903, standard agents for insomnia and sedation

Habit-forming

Only a handful commonly used today due in part to the safety and efficacy of: BENZODIAZEPINES

Sedative-Hypnotics: Barbiturates Four categories: Ultrashort mephobexital, thiamylal, thiopental Short pentobarbital, secobarbital Intermediate aprobarbital, butabarbital Long phenobarbital

Four categories:

Ultrashort

mephobexital, thiamylal, thiopental

Short

pentobarbital, secobarbital

Intermediate

aprobarbital, butabarbital

Long

phenobarbital

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

Barbiturates have a very narrow therapeutic index.

Therapeutic Index

Dosage range within which the drug is effective but above which is rapidly toxic.

Sedative-Hypnotics: Barbiturates Mechanism of Action Site of action: Brain stem (reticular formation) Cerebral cortex By inhibiting GABA, nerve impulses traveling in the cerebral cortex are also inhibited.

Mechanism of Action

Site of action:

Brain stem (reticular formation)

Cerebral cortex

By inhibiting GABA, nerve impulses traveling in the cerebral cortex are also inhibited.

Sedative-Hypnotics: Barbiturates Drug Effects Low doses: Sedative effects High doses: Hypnotic effects (also lowers respiratory rate) Notorious enzyme inducers

Drug Effects

Low doses: Sedative effects

High doses: Hypnotic effects (also lowers respiratory rate)

Notorious enzyme inducers

Sedative-Hypnotics: Barbiturates Therapeutic Uses Hypnotics Sedatives Anticonvulsants Surgical procedures

Therapeutic Uses

Hypnotics

Sedatives

Anticonvulsants

Surgical procedures

Sedative-Hypnotics: Barbiturates Side Effects Body System Effects CNS Drowsiness, lethargy, vertigo mental depression, coma Respiratory Respiratory depression, apnea, bronchospasms, cough

Side Effects

Body System Effects

CNS Drowsiness, lethargy, vertigo mental depression, coma

Respiratory Respiratory depression, apnea, bronchospasms, cough

Sedative-Hypnotics: Barbiturates Side Effects Body System Effects GI Nausea, vomiting, diarrhea Other Agranulocytosis, vasodilation, hypotension, Stevens-Johnson syndrome

Side Effects

Body System Effects

GI Nausea, vomiting, diarrhea

Other Agranulocytosis, vasodilation, hypotension, Stevens-Johnson syndrome

Sedative-Hypnotics: Barbiturates Toxicology Overdose frequently leads to respiratory depression, and subsequently, respiratory arrest. Can be therapeutic: Anesthesia induction Uncontrollable seizures: “phenobarbital coma”

Toxicology

Overdose frequently leads to respiratory depression, and subsequently, respiratory arrest.

Can be therapeutic:

Anesthesia induction

Uncontrollable seizures: “phenobarbital coma”

Sedative-Hypnotics: Barbiturates Drug Interactions Additive effects: ETOH, antihistamines, benzodiazepines, narcotics, tranquilizers Inhibited metabolism: MAOIs will prolong effects of barbiturates Increased metabolism: Reduces anticoagulant response, leading to possible clot formation

Drug Interactions

Additive effects:

ETOH, antihistamines, benzodiazepines, narcotics, tranquilizers

Inhibited metabolism:

MAOIs will prolong effects of barbiturates

Increased metabolism:

Reduces anticoagulant response, leading to possible clot formation

CNS Depressants: Benzodiazepines Most frequently prescribed sedative-hypnotics Most commonly prescribed drug classes Favorable side effects Efficacy Safety

Most frequently prescribed sedative-hypnotics

Most commonly prescribed drug classes

Favorable side effects

Efficacy

Safety

CNS Depressants: Benzodiazepines Classified as either: Sedative-hypnotic or Anxiolytic (Medication that relieves anxiety)

Classified as either:

Sedative-hypnotic or Anxiolytic

(Medication that relieves anxiety)

CNS Depressants: Benzodiazepines Sedative-Hypnotic Type Long-Acting: flurazepam (Dalmane), quazepam (Doral) Short-Acting: estazolam (Prosom), temazepam (Restoril), triazolam (Halcion)

Sedative-Hypnotic Type

Long-Acting:

flurazepam (Dalmane), quazepam (Doral)

Short-Acting:

estazolam (Prosom), temazepam (Restoril),

triazolam (Halcion)

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

Anxiolytic Type

alprazolam (Xanax)

chloridiazepoxide (Librium)

diazepam (Valium)

lorazepam (Ativan)

midazolam (Versed)

zolpidem (Ambien) and zaleplon (Sonata)

(nonbenzodiazepine hypnotic agents, share characteristics)

CNS Depressants: Benzodiazepines Mechanism of Action Depress CNS activity Affect hypothalamic, thalamic, and limbic systems of the brain Benzodiazepine receptors

Mechanism of Action

Depress CNS activity

Affect hypothalamic, thalamic, and limbic systems of the brain

Benzodiazepine receptors

CNS Depressants: Benzodiazepines Drug Effects Calming effect on the CNS Useful in controlling agitation and anxiety

Drug Effects

Calming effect on the CNS

Useful in controlling agitation and anxiety

CNS Depressants: Benzodiazepines Therapeutic Uses Sedation Sleep induction Skeletal muscle relaxation Anxiety relief Treatment of alcohol withdrawal Agitation Depression Epilepsy Balanced anesthesia

Therapeutic Uses

Sedation

Sleep induction

Skeletal muscle relaxation

Anxiety relief

Treatment of alcohol withdrawal

Agitation

Depression

Epilepsy

Balanced anesthesia

CNS Depressants: Benzodiazepines Side Effects Mild and infrequent Headache Drowsiness Dizziness Vertigo Lethargy Paradoxical excitement (nervousness) “Hangover effect”

Side Effects

Mild and infrequent

Headache Drowsiness Dizziness Vertigo Lethargy Paradoxical excitement (nervousness) “Hangover effect”

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

Before beginning therapy, perform a thorough history regarding allergies, use of other medications,health history, and medical history.

Obtain baseline vital signs and I & O, including supine and erect BPs.

Assess for potential disorders or conditions that may be contraindications, and for potential drug interactions.

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

Give 15 to 30 minutes before bedtime for maximum effectiveness in inducing sleep.

Most benzodiazepines (except flurazepam) cause REM rebound and a tired feeling the next day; use with caution in the elderly.

Patients should be instructed to avoid alcohol and other CNS depressants.

CNS Depressants: Nursing Implications Check with physician before taking any other medications, including OTC medications. It may take 2 to 3 weeks to notice improved sleep when taking barbiturates. Abruptly stopping these medications, especially barbiturates, may cause rebound insomnia.

Check with physician before taking any other medications, including OTC medications.

It may take 2 to 3 weeks to notice improved sleep when taking barbiturates.

Abruptly stopping these medications, especially barbiturates, may cause rebound insomnia.

CNS Depressants: Nursing Implications Safety is important Keep side rails up Do not permit smoking Assist patient with ambulation (especially the elderly) Keep call light within reach Monitor for side effects

Safety is important

Keep side rails up

Do not permit smoking

Assist patient with ambulation (especially the elderly)

Keep call light within reach

Monitor for side effects

CNS Depressants: Nursing Implications Monitor for therapeutic effects Increased ability to sleep at night Fewer awakenings Shorter sleep induction time Few side effects, such as hangover effects Improved sense of well-being because of improved sleep

Monitor for therapeutic effects

Increased ability to sleep at night

Fewer awakenings

Shorter sleep induction time

Few side effects, such as hangover effects

Improved sense of well-being because of improved sleep