Transcript Unit 11: Drugs that affect the CNS

Nancy Pares, RN, MSN
NURS 1950
Metropolitan Community College
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Seizures
◦ Abnormal or uncontrolled neuronal
discharges in the brain
◦ affect
 Consciousness
 Motor activity
 Sensation
◦ Symptom of an underlying disorder-not a
disease itself
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Infectious diseases
Trauma
Metabolic disorders
Vascular diseases
Pediatric disorders
Neoplastic diseases
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Most common serious neurologic problem
affecting children
May present as an acute situation, or they
may occur on a chronic basis
Figure 15.1 EEG recordings showing the differences between normal, absence seizure, and generalized
tonic–clonic seizure tracings
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High dose of local anesthetics
Drug abuse
Withdrawal from alcohol
Withdrawal from sedative-hypnotics
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Involuntary violent spasm of large
muscles of the face, neck, arms and
legs
Not synonymous with seizure
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Signs and symptoms
◦ Related to the area of the brain with
abnormal activity
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Types-based on International
Classification
◦ Partial (focal)
◦ Generalized
◦ Special epileptic syndromes
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Occur in limited portion of brain
Point of origin: abnormal focus or foci
Clients experience
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Feeling that is vague
Hallucinations with all senses
Extreme emotions
Twitching of arms, legs or face
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Altered levels of consciousness
Involve sensory, motor, autonomic
symptoms
Aura commonly precedes seizure
No memory of seizure
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Travel throughout the entire brain
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Subcatagories
◦ Absence
◦ Atonic
◦ Tonic-clonic
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Common in children
Subtle symptoms
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Staring
Transient loss of consciousness
Eyelid fluttering
Myclonic jerks
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Usually last only a few seconds
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Characterized by stumbling or falling
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Most common
Usually preceded by aura
Tonic phase
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Intense muscle contractions
Hoarse cry at onset
Loss of bowel/bladder control
Shallow breathing
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Clonic phase
◦ Alternating contraction and relaxation of
muscles
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Postictal state (post seizure)
◦ Drowsiness, disorientation, deep sleep
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Febrile seizures
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Myoclonic seizures
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Status epilepticus
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Last one –two minutes
Tonic clonic motor activity
Common in 3-5 year olds
Occur with rapid rise in body
temperature
Affect 5% of all children
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Large jerking body movements
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Quick contraction of major muscles
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Stumbling and falling
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Similar to normal infantile Moro reflex
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Medical emergency
Continuously repeating seizure
Common with generalized tonic-clonic
Continuous muscle contractions
◦ May compromise airway
◦ May cause hypoglycemia, hypothermia,
acidosis
◦ May produce lactic acid
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The choice of drug depends upon
◦ Type of seizure
◦ Client history and diagnostic studies
◦ Pathologic process causing seizures
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Patient placed on low initial dose
Amount gradually increased
If seizure activity remains, different
medication added in small increments
Newer antiseizure drugs have less adverse
side effects than older drugs
Most cases require only a single drug
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Study included patients with epilepsy, bipolar
disorder, psychoses, migraines, and
neuropathic pain
Popular antiseizure examples found to almost
double risk of suicidal behavior and ideation
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Goal: suppress neuronal activity enough to
prevent abnormal or repetitive firing
Drugs act through three mechanisms:
◦ Stimulating an influx of chloride ions
◦ Delaying an influx of sodium
◦ Delaying an influx of calcium
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Directed at controlling movement of
electrolytes across neuronal membranes or
affecting neurotransmitter balance
Some drugs act by more than one mechanism
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GABA= gamma aminobutyric acid
◦ Primary neuro transmitter of brain.
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Drugs that potentiate GABA action
◦ Barbiturates
◦ Benzodiazepines
◦ Misc. agents
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Prototype: phenobarbital (Luminal)
◦ Mechanism of action
 Changing the action of GABA
◦ Primary use
 Controlling seizures
◦ Adverse effects
 Dependence, drowsiness, vitamin deficiencies,
laryngeospasm
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Prototype: diazepam (Valium)
◦ Mechanism of action
 Similar to barbiturates, but safer
◦ Primary use
 Short term seizure control
◦ Adverse effects
 Drowsiness and dizziness
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Prototype: valproic acid (Depakene)
Mechanism of action:
◦ similar to benzo’s and barbiturates
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Primary use
◦ Adjunct therapy
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Adverse effects:
◦ Sedation, drowsiness, GI upset, prolonged
bleeding time
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Prototype: phenytoin (Dilantin)
Mechanism of action:
◦ Desensitize sodium channel blockers
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Primary use
◦ Treatment of all types of seizures, except absence
seizures
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Adverse effects:
◦ CNS depression, gingival hyperplasia, skin rash,
cardiact dysrhythmias, and hypotension
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Prototype drug: valproic acid (Depakene)
Mechanism of action:
◦ Desensitize sodium channels
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Primary use:
◦ Absence seizures
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Adverse effects:
◦ Limited CNS depression, visual disturbances, ataxia,
vertigo, HA, GI, hepatotoxicity, pancreatitis
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Prototype: ethosuximide (Zarontin)
Mechanism of action
◦ Suppress calcium influx
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Primary use
◦ Absence seizures
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Adverse effects:
◦ Rare, but include drowsiness, dizziness, lethargy
◦ Rare, but serious: lupus, leukopenia, aplastic
anemia, Stevens-Johnson syndrome
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Barbiturates:
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Monitor for liver and kidney function
Category D in pregnancy
Depletion of nutrients
Alcohol and ginko biloba interactions
Client teaching
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Use reliable contraception
Immediately report pregnancy
Report excessive bleeding,drowsiness, bone pain
Avoid alcohol and gingko biloba
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Monitor for drug abuse potential
Pregnancy risk (category D)
Contraindicated in narrow angle glaucoma
Liver and kidney function monitored
Respiratory depression
In event of overdose
◦ Give flumazenil (Romazicon)
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Give IV valium and ativan
Do not mix with other drugs in IV line
Client teaching
◦ Avoid ETOH, OTC drugs, herbal preps,
nicotine, driving and hazardous activities
◦ Rebound seizures if d/c abruptly
◦ Take with food
◦ These drugs most often used illegally
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Monitor serum drug levels, liver and kidney
function
Monitor for bleeding disorders
Fatal hepatotoxicity can occur
Contraindicated
◦ Hx of heart block or seizures due to low BS
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Client teaching
◦ Routine labs; report s/s of toxicity, bleeding,
pregnancy, hypoglycemia
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Monitor for liver and kidney function
Pregnancy category C
Adverse reactions:
◦ Drowsiness, HA, euphoria, n/v, weight loss, abd.
Pain
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Life threatening reactions:
◦ Mental depression with suicide intent
◦ Blood dyscrasias and Stevens-Johnson syndrome
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Symptoms of overdose
◦ CNS depression, stupor, ataxia, coma
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Client teaching
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Report mood changes or suicidal thoughts
Avoid driving and hazardous activities
Take with food
Do not stop abruptly
Report weight loss and anorexia
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Start with smallest dose of med
Add additional drugs, if needed
Monitor serum drug levels
Withdrawal of meds
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Seizure free for three years
Done gradually
Resume meds if seizures return
Knowledge of rebound seizures
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Disturbed sensory perception RT
seizure activity
Risk for injury RT seizure activity
Deficient knowledge RT disease/drugs
Noncompliance RT drug regime
Noncompliance RT serum lab testing
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Absence/reduction in number of
seizures
No injury during seizure
Understanding of disease
Understanding of drug regimen
Compliance with lab testing
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Objective 8: Describe common symptoms of
Parkinson’s Disease.
Objective 9: Describe the role of dopamine in
the body.
Objective 10: name the preparations used to
treat Parkinson’s.
Objective 11: describe the role of the
anticholinergic drugs in the treatment of
Parkinson’s
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Objective 12 Apply nursing process as it
relates to the care of the client with
Parkinson’s and accompanying drug therapy.
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Second most common CNS disease
Progressive loss of dopamine
Tremor, muscle rigidity
Abnormal movement and posture
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Symptoms known as parkinsonism
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Tremors
Muscle rigidity
Bradykinesia
Postural instability
Affective flattening
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Primarily affects muscle movement
Patients often experience other health issues
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Anxiety, depression
Sleep disturbances
Dementia
Autonomic nervous system disturbances
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Degeneration and destruction of dopamineproducing neurons
◦ Substantia nigra portion of brain
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Corpus striatum
◦ Normally controls unconsciousness muscle
movement
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Dopamine and acetylcholine in corpus
striatum
◦ Affect balance, posture
◦ Affect muscle tone, involuntary movement
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Absence of dopamine
◦ Allows acetylcholine stimulation
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Restores dopamine function
Blocks acetylcholine
Extrapyramidal side effects (EPS)
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Restore balance of dopamine and
acetylcholine in brain
◦ Dopaminergic drugs
 Dopaminergic adjunct agents
◦ Anticholinergics (cholinergic blockers)
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Restore balance of dopamine and
acetylcholine
Dopaminergic examples
◦ Levodopa (Larodopa),
◦ Levodopa and carbidopa (Sinemet)
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Levodopa (Larodopa) is drug of choice
◦ Increases biosynthesis of dopamine within nerve
terminals
◦ Effectiveness boosted by combining with carbidopa
(Sinemet)
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Inhibit enzymes
◦ Example: Tolcapone (Tasmar)
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Activate dopamine receptors (dopamine
agonists)
◦ Example: Ropinirole (Requip)
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Cause dopamine release from nerve terminals
◦ Example: Amantadine (Symmetrel)
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Centrally acting
Block acetylcholine
◦ Inhibits overactivity in brain
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Used in early stages
Examples
◦ Benztropine mesylate (Cogentin)
◦ Triexyphenidyl hydrochloride (Artane)
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Reduce requirement for L-dopa
Increase concentration of existing dopamine;
improve motor fluctuations
Examples:
◦ entacapone (Comtan)
◦ tolcapone (Tasmar)
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Prototype drug: levodopa (Larodopa)
• Mechanism of action: Increases
biosynthesis of dopamine within nerve
terminals
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Primary use: to restore dopamine function or
stimulate dopamine receptors within the
brain
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Adverse effects: dizziness, light-headedness,
sleep dysfunction, fatigue, nausea, vomiting,
constipation, orthostatic hypertension,
dystonia, dyskinesia
Click here to view an animation on the topic of levadopa.
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Prototype drug: benztropine mesylate
(Cogentin)
Mechanism of action: block acetylcholine;
inhibit overactivity in brain
Primary use: in early stages of disease
Adverse effects: dry mouth, blurred vision,
photophobia, urinary retention,
constipation, tachycardia, glaucoma
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Contraindicated in narrow-angle glaucoma
Monitor for hypotension and tachycardia
Look for symptoms of drug toxicity
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Increase fiber and fluids
Avoid food and drugs high in pyridoxine
May take several months for full effect
Abruptly stopping the drug may cause
Parkinsonism crisis
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Relieve dry mouth with frequent drinks or
sugarless hard candy
Take with food or milk to prevent GI upset
Avoid alcohol
Wear dark glasses; avoid bright sunlight
Do not stop taking abruptly
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Assess baseline vitals
Monitor for hypotension
Monitor for change in mental status or mood
Monitor for dizziness, insomnia, anorexia
Clients with narrow-angle glaucoma should
not take revastigmine (Exelon)
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Sedative:
◦ An agent that calms nervousness, irritability
and excitement
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Hypnotic
◦ An agent that induces sleep
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Objective 14: describe actions, use and s/e of
barbiturates (covered earlier)
Objective 15: identify the commonly used
barbiturates and benzo (covered earlier)
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Results from damage to the motor area
of the cerebral cortex
Conditions:
◦ Cerebral palsy
◦ severe head injury, spinal cord injury or
lesions
◦ stroke
◦ dystonia
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Goals of muscle relaxants
◦ Minimize discomfort
◦ Increase ROM
◦ Improve ability to function independently
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Centrally acting muscle relaxants
◦ Prototype: cyclobenzaprine (Flexeril)
◦ Mechanism of action
 Inhibits upper motor neuron activity
 Alters simple spinal reflexes, causes CNS depression
◦ Primary Use
 Treat localized spasms
◦ Adverse effects
 CNS depression, hepatic toxicity, physical dependence,
anticholinergic effects
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Direct acting antispasmodics
◦ Prototype: dantrolene (Danantrium)
◦ Mechanism of action
 Interferes with release of calcium ions in skeletal
muscle
◦ Primary use
 Relieve dystonias and leg cramps
◦ Adverse effects
 Hepatic toxicity, muscle weakness, drowsiness,
diarrhea
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Assessment
◦ Monitor pain, LOC, vital signs
◦ Monitor muscle tone, ROM, degree of spasms
◦ Monitor labs
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Nursing Dx
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Pain
Impaired physical mobility
Risk for injury
Deficient knowledge
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Goals
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Decrease pain
Increase range of motion (ROM)
Reduce muscle spasms
No adverse effects of drugs
Knowledge of drug regimen