Chapter 18: Depressants Flashcards
Classification of CNS Depressants
Sedative-hypnotics
General anesthetics
Analgesics
Opioid and nonopioid analgesics
Anticonvulsants
Antipsychotics
Antidepressants
The inability to fall asleep or remain asleep
Insomnia
Two phases of normal sleep
REM and NREM
Intervals of REM and NREM sleep
90 minutes
Transition period between wakefulness and sleep
Lasts around 5-10 mins
NREM 1
Body temperature drops and heart rate begins to slow
Lasts approximately 20 minutes
NREM 2
Muscles relax, bp and breathing rate drop
Deepest sleep occurs
NREM 3
Brain becomes more active
Body becomes relaxed and immobilized
Dreams occur and eyes move rapidly
REM
What are nonpharmacologic methods to promote sleep?
- Arise at a specific hour in the morning
- Take a few or no daytime naps.
- Avoid smoking nicotine and drinks that contain caffeine and alcohol 6 hours before bedtime.
- Avoid heavy meals or strenuous exercise before bedtime.
- Take a warm bath, listen to quiet music or perform other soothing activities before bedtime.
- Decrease exposure to loud noises.
- Avoid drinking too much fluid before sleep.
- Drink warm milk before bedtime.
These are commonly prescribed as treatment for sleep disorders
Sedative-hypnotics
Mildest form of CNS depression
Sedation/Sedatives
Increasing the drug dose of sedatives can produce…
Hypnotic effect, form of natural sleep
What happens with high doses of sedative-hypnotics?
Anesthesia may be achieved
Useful in achieving sleep because they allow the patient to awaken early in morning without lingering side effects
Short-acting hypnotics
Useful for sustaining sleep but patient may experiences drowsiness or hangover in the morning
Long-acting hypnotics
Contraindications of Hypnotics
Patients with severe respiratory disorders and pregnant
Only major sedative-hypnotic approved for long term use and used for treating chronic insomnia
Ramelteon
Common Side effects and adverse effects of Sedative-Hypnotics
Hangover - residual drowsiness, intermediate and long acting hypnotics are the cause.
REM Rebound - results in vivid dreams and nightmares, occurs after prolonged used and abruptly stopping
Dependence - result of chronic hypnotic use
Tolerance - results when there is a need to increase dosage over time to obtain desired effect.
Excessive depression - long-term use is the cause
Respiratory depression - high doses can suppress respiratory center in medulla
Hypersensitivity - skin rashes and urticaria can result when taking barbiturates.
Categories of Sedative-Hypnotics
Barbiturates
Benzodiazepines
Nonbenzodiazepines
Classification of Barbiturates
Long-acting - includes phenobarbital, used to control seizures and epilepsy
Intermediate-acting - butabarbital, useful as sleep sustainers for maintaining long periods of sleep.
Short-acting - secobarbital, used for procedure sedation
How long should barbiturates be used?
Short term, 2 weeks or less
Classification of Barbiturates as CSS
Short-acting - II
Intermediate-acting - III
Long-acting - IV
Examples of short-acting barbiturates
Secobarbital sodium CSS II
Pentobarbital CSS II
Pentobarbital and secobarbital are used for?
Short-term treatment of insomnia
Control of seizures
Preoperative anxiety
Sedation induction
Example of Intermediate-acting barbiturate
Butabarbital Sodium
Example of Long-acting barbiturate
Phenobarbital CSS IV
Depressants that produce sedation, hypnosis, anxiety and muscle spasm relief and reduce seizures. Drug prescribed as sedative-hypnotics for inducing sleep
Benzodiazepines
Examples of Benzodiazepines
Alprazolam - anxiety and panic treatment
Estazolam - insomnia treatment
Lorazepam - sedation induction and anxiety relief
Temazepam - insomnia treatment
Triazolam - insomnia management
A benzodiazepine antagonist
Flumazenil
Examples of Nonbenzodiazepines
Zolpidem tartrate
Eszopiclone
Zaleplon
Half-life of Benzodiazepines
8-24 hours
Alprazolam food interaction
Grapefruit - increases drug levels
Green tea - decreases drug effects
A phase of our daily life cycle when the brain and body rest and rejuvenate.
SLEEP
A nonbenzodiazepine that is used for short-term treatment of insomnia
Zolpidem
A sedative-hypnotic drug under melatonin agonists for insomnia treatment
Ramelteon
Adverse effects of Ramelteon
Drowsiness and dizziness
Fatigue, headache and nausea
Suicidal Ideation
What type of sedative-hypnotics should not be prescribed to older adults for sleep? and what is the alternative?
Barbiturates
Benzodiazepines, estazolam, temazepam, triazolam
Classification of anesthetics
General and local
Anesthetic that depresses CNS, alleviate pain and cause a LOC.
General anesthetics
The first anesthetic used for surgery, also called the “laughing gas”.
Nitrous Oxide
Pathophysiology of inhalation anesthetics
- Lipid structure of cell membranes is altered > impaired physiologic functions
- GABA is activated to the GABA receptor > Decreases action potentials of neurons
- Ascending reticular activating system is altered > neurons cease to transmit information to the brain.
A Balance Anesthesia is
A combination of drugs frequently used in general anesthesia, may include the ff:
- Hypnotic given the night before
- Premedication with opioid analgesic or benzodiazepine + atropine given about 1 hours before surgery
- Short-acting nonbarbiturate (propofol)
- Inhaled gas, combination of inhalation anesthetic, nitrous oxide, oxygen
- Muscle relaxant PRN
Why is balanced anesthesia better than general anesthesia?
Minimizes cardiovascular problems and organ function disturbance
Decreases the amount GA need
Reduces possible postanesthesia nausea and vomiting
Decreases pain
Stages of Anesthesia
- Analgesia - begin with consciousness and ends with LOC
- Excitement or delirium - produces LOC causes by depression of cerebral cortex
- Surgical - procedure is done in this stage, respiration becomes shallower, RR increase
- Medullary paralysis - toxic stage, respirations are lost, circulatory collapse occurs.
Inhalation Anesthesias Examples
Volatile liquids:
Halothane - highly potent anesthetic
Enflurane - can depress respiratory function
Isoflurane - frequently used in inhalation therapy
Desflurane
Sevoflurane - for induction and maintenance during surgery
Gas:
Nitrous Oxide
IV Anesthetics examples
Ultra-short-acting barbiturates:
Methohexital sodium - used for induction, part of balanced anesthesia
Thiamylal sodium - used for induction, anesthesia for electroshock therapy
Benzodiazepines:
Diazepam - induction of anesthesia
Midazolam - for endoscopic procedures
Adverse effects of inhalation anesthetics
Respiratory depression
Hypotension
Dysrhythmias
Hepatic dysfunction
Used for general anesthesia or induction of anesthesia
IV Anesthetics
Preferred anesthetics for outpatient surgery
IV Anesthetics
Commonly used to provide a Total Intravenous Anesthetic (TIVA)
Propofol, droperidol, etomidate and ketamine hydrochloride
Adverse effects of IV anesthetics
Respiratory and Cardiovascular depression
Anesthetic that is limited to mucous membranes, broken or unbroken skin surfaces and burns
Topical anesthetics
Forms of topical anesthetics
Gels, cream, solutions, liquid spray, ointment, powder
Type of anesthetic that blocks pain at the site where drug is administered by preventing conduction of nerve impulses
Local Anesthesia
Local anesthetics are useful in
Dental procedures
Suturing skin lacerations
Minor surgeries at a localized area
Diagnostic procedure (lumbar puncture)
Provided analgesia for surgery in lower or upper extremities
Two groups of local anesthetics
Ester
Amides - very low incidence of allergic reactions
Examples of local anesthetics
Short-acting:
Chloroprocaine hydrochloride
Procaine hydrochloride
Moderate acting:
Lidocaine hydrochloride
Prilocaine hydrochloride
Long-acting:
Bupivacaine hydrochloride
Dibucaine hydrochloride
Is performed by placing a needle between the lumbar vertebrae and through the dura
Spinal Anesthesia
Where is the local anesthetic injected in spinal anesthesia?
Subarachnoid space below first lumbar space (L1) in adults and 3rd lumbar space (L3) in children
Results from penetration of the anesthetic into the subarachnoid space
Spinal block
Placement of local anesthetic in the epidural space
Epidural block
An epidural block placed by administering a local anesthetic through the sacral hiatus
Caudal block
Given at the lower end of the spinal column to block the perineal area
Saddle block
