(Ch 19) Sedative-Hypnotic and Anxiolytic Flashcards
What are CNS Depressants?
CNS depressants are medications that suppress the transmission of information throughout the central nervous system.
What are the 7 Classifications of CNS Depressants
There are 7 classifications of CNS depressants.
They are:
- Sedative-hypnotics
- General and local anesthetics
- Analgesics
- Narcotic analgesics 5. Anticonvulsants
- Antipsychotics
- Antidepressants
Define anxiety:
Ex of symptoms involved:
An unpleasant emotional state consisting of apprehension, tension, and feelings of danger without a real or logical cause
Tachycardia- Tachypnea -Sweating -Trembling Weakness
What are the 4 major classes of drugs used to treat anxiety?
1. Benzodiazepines—the most frequently used drugs for anxiety, most important group, used as sedative and hypnotic agents.
2. Azapirones—(5-HT 1a receptor agonist, ex: Buspirone) are a class of drugs used as anxiolytics, antidepressants, and antipsychotics.
They are commonly used as add-ons to other antidepressants, such as selective serotonin reuptake inhibitors (SSRIs
3. Barbiturates—rarely used today because of severe side effects and a low therapeutic index. These drugs have generally been replaced by the benzodiazepines.
4. β -adrenoceptor antagonists (e.g. propranolol). They are used to treat some forms of anxiety,
where physical symptoms (sweating, tremor, and tachycardia), are troublesome. They are not used as hypnotics.
Ex: Benzodiazepines and their approximate duration of action:
Short-Acting
Short-Acting (2 to 8 hr):
- Triazolam (Halcion)
- Oxazepam (Serax)
- Midazolam (Versed)
- Clonazepam (Klonopin)
Ex: Benzodiazepines and their approximate duration of action:
Intermediate-Acting
Intermediate-Acting (10 to 20 hr):
- Temazepam (Restoril)
- Lorazepam (Ativan)
- Alprazolam (Xanax)
- Alprazepam
Ex: Benzodiazepines and their approximate duration of action:
Long-Acting
Long-Acting (1 to 3 days):
1. Chlordiazepoxide (Librium)
2. Diazepam (Valium)
3. Flurazepam (Dalmane)
4. Clonazepam
Benzodiazepines:
Bind strongly to what ?
Are inactivated by what ?
Benzodiazepines are well absorbed when given orally.
- They bind strongly to plasma proteins, however, many of them accumulate gradually in the body fat (i.e. they are highly lipid soluble).
- Benzodiazepines are inactivated by the liver and excreted in the urine.
Benzodiazepines:
Pharmacodynamics ?
Pharmacodynamics
Act by binding to a specific regulatory site on the GABAA receptor, thus enhancing the inhibitory effects of GABA. Central nervous system effects of benzodiazepines include:
- Reduction of anxiety and aggression.
- Sedation and induction of sleep.
- Reduction of muscle tone and coordination.
- Anticonvulsant effects
Benzodiazepines
Clinical Uses:
Clinical Uses
Treatment insomnia
Anxiety
Preoperative mediations
Acute alcohol withdrawal
As anticonvulsants
Chronic muscle spasm and spasticity
Benzodiazepines:
Side-effects
Side-effects
Toxic effects due to acute overdosage causes prolonged sleep.
Side-effects occurring during normal therapeutic use includes:
drowsiness, confusion, amnesia, and impaired motor coordination.
Tolerance and dependance: Pharmacokinetic and tissue tolerance and also cause physical dependance.
i.e. stopping benzodiazepines treatment after weeks or months causes an increase in symptoms of anxiety.
Benzodiazepine
Pharmacokinetic:
Pharmacokinetic:
Absorbed from GI tract; crosses blood– brain barrier; metabolized in liver, and excreted in urine
What is GABA?
GABA (γ-aminobutyric acid) is the major inhibitory neurotransmitter of the CNS.
How do benzodiazepines work?
- When benzodiazepines bind to specific receptors that are separate from but adjacent to the GABAA receptor, they potentiate the binding of GABA to its own receptor.
- The binding of GABA to its own receptor results in increased chloride ion conductance, cell membrane hyperpolarization, and decreased initiation of action potentials.
Remember that benzodiazepines do not bind to GABA receptors—they bind adjacent to them
What are the therapeutic indications for benzodiazepines?
Name 4
These drugs are used clinically as muscle relaxants and in the treatment of the following:
1. Anxiety disorders
2. Panic disorders—alprazolam is the drug of choice.
Status epilepticus—diazepam is the drug of choice.
3. Sleep disorders—flurazepam or temazepam.
4. Alcohol withdrawal—diazepam is most commonly used.
Are benzodiazepines effective for controlling pain as well as anxiet?
No. They have little analgesic effect.
Benzodiazepine:
What is their route of administration?
PO, IV, or IM
Where are benzodiazepines metabolized?
They are metabolized in the liver and excreted in the urine. Many of the benzodiazepines have active metabolites.
Does dependence occur?
Yes. Prolonged use can result in dependence. Abrupt discontinuation can result in withdrawal symptoms, including confusion, anxiety, and agitation.
What types of symptoms may a patient taking benzodiazepines experience?
- Drowsiness and confusion—the most common side effects: Ataxia (loss of full controll of bodily movements) Dizziness
- Respiratory depression and death if taken with other CNS depressants such as ethanol
What are Sedative-hypnotics?
Ex:
Sedative-hypnotics (Benzodiazepines) , the mildest form of central nervous system depressant, are given in low doses to diminish physical and mental responses without affecting consciousness.
Short-acting sedative-hypnotics are prescribed to help fall asleep, allowing the patient to awake early without a lingering after effect.
Intermediate-acting sedative-hypnotics are used for sustaining sleep and have residual drowsiness after waking.
NOTE: Sedative-hypnotics are not prescribed for patients who have severe respiratory disorders or who are pregnant.
Sedative-hypnotics are prescribed for short-term use because the patient can develop a tolerance of and dependency on the medication. Avoid chronic use of sedative-hypnotics.
5 - HT1A receptor agonist
- Provide Ex:*
- Define:*
- SE:*
Buspirone
is a potent agonist of. 5 - HT1A receptors. Anxiolytic effects take days to weeks to develop.
- Buspirone does not cause sedation*, motor incoordiation and withdrawal effects.
- The main side effects*: are nausea, dizziness, headache, and restlessness.
Schedule IV: Drugs
- Benzodiazepine’s:*
- Examples? 5*
- Flurazepam hydrochloride (Dalmane)
- Diphenhydramine (Benadryl)
- Temazepam (Restoril)
- Triazolam (Halcion)
- Zolpidem (Ambien)
SEDATIVE–HYPNOTIC–BENZODIAZEPINE–SCHEDULE IV:
Use:
- Short-term treatment of insomnia* (up to 4 weeks); a. a. reduces sleep induction time
b. reduces number of nocturnal awakenings; increases length of sleep.
SEDATIVE–HYPNOTIC–BENZODIAZEPINE–SCHEDULE IV:
How it works:
• Enhances action of inhibitory neurotransmitter gamma-aminobutyric acid (GABA), producing hypnotic effect caused by CNS depression
SEDATIVE–HYPNOTIC–BENZODIAZEPINE–SCHEDULE IV:
Adult dose
1• Flurazepam hydrochloride (Dalmane) 15–30 mg at bedtime (15 mg for elderly)
2• Zolpidem (Ambien): PO 10 mg at bedtime (elderly, debilitated 5 mg)
3• Triazolam (Halcion): PO 0.125–0.5 mg at bedtime (elderly 0.0625–0.125 mg)
4• Temazepam (Restoril): PO 15–30 mg at bedtime (elderly 7.5–15 mg)