unit 11: drugs that affect the cns nancy pares, rn, msn nurs 1950 metropolitan community college
TRANSCRIPT
Seizures◦ Abnormal or uncontrolled neuronal
discharges in the brain◦ affect
Consciousness Motor activity Sensation
◦ Symptom of an underlying disorder-not a disease itself
Infectious diseases Trauma Metabolic disorders Vascular diseases Pediatric disorders Neoplastic diseases
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
High dose of local anesthetics Drug abuse Withdrawal from alcohol Withdrawal from sedative-hypnotics
Involuntary violent spasm of large muscles of the face, neck, arms and legs
Not synonymous with seizure
Signs and symptoms◦ Related to the area of the brain with
abnormal activity Types-based on International
Classification◦ Partial (focal)◦ Generalized◦ Special epileptic syndromes
Occur in limited portion of brain Point of origin: abnormal focus or foci Clients experience
◦ Feeling that is vague◦ Hallucinations with all senses◦ Extreme emotions◦ Twitching of arms, legs or face
Altered levels of consciousness Involve sensory, motor, autonomic
symptoms Aura commonly precedes seizure No memory of seizure
Common in children Subtle symptoms
◦ Staring◦ Transient loss of consciousness◦ Eyelid fluttering◦ Myclonic jerks
Most common Usually preceded by aura Tonic phase
◦ Intense muscle contractions◦ Hoarse cry at onset◦ Loss of bowel/bladder control◦ Shallow breathing
Clonic phase◦ Alternating contraction and relaxation of
muscles
Postictal state (post seizure)◦ Drowsiness, disorientation, deep sleep
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
Large jerking body movements
Quick contraction of major muscles
Stumbling and falling
Similar to normal infantile Moro reflex
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
The choice of drug depends upon◦ Type of seizure
◦ Client history and diagnostic studies
◦ Pathologic process causing seizures
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
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
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
Directed at controlling movement of electrolytes across neuronal membranes or affecting neurotransmitter balance
Some drugs act by more than one mechanism
GABA= gamma aminobutyric acid ◦ Primary neuro transmitter of brain.
Drugs that potentiate GABA action◦ Barbiturates◦ Benzodiazepines◦ Misc. agents
Prototype: phenobarbital (Luminal)◦ Mechanism of action
Changing the action of GABA◦ Primary use
Controlling seizures◦ Adverse effects
Dependence, drowsiness, vitamin deficiencies, laryngeospasm
Prototype: diazepam (Valium)◦ Mechanism of action
Similar to barbiturates, but safer◦ Primary use
Short term seizure control◦ Adverse effects
Drowsiness and dizziness
Prototype: valproic acid (Depakene) Mechanism of action:
◦ similar to benzo’s and barbiturates Primary use
◦ Adjunct therapy Adverse effects:
◦ Sedation, drowsiness, GI upset, prolonged bleeding time
Prototype: phenytoin (Dilantin) Mechanism of action:
◦ Desensitize sodium channel blockers Primary use
◦ Treatment of all types of seizures, except absence seizures
Adverse effects:◦ CNS depression, gingival hyperplasia, skin rash,
cardiact dysrhythmias, and hypotension
Prototype drug: valproic acid (Depakene) Mechanism of action:
◦ Desensitize sodium channels Primary use:
◦ Absence seizures Adverse effects:
◦ Limited CNS depression, visual disturbances, ataxia, vertigo, HA, GI, hepatotoxicity, pancreatitis
Prototype: ethosuximide (Zarontin) Mechanism of action
◦ Suppress calcium influx Primary use
◦ Absence seizures Adverse effects:
◦ Rare, but include drowsiness, dizziness, lethargy◦ Rare, but serious: lupus, leukopenia, aplastic
anemia, Stevens-Johnson syndrome
Barbiturates:◦ Monitor for liver and kidney function◦ Category D in pregnancy◦ Depletion of nutrients◦ Alcohol and ginko biloba interactions◦ Client teaching
Use reliable contraception Immediately report pregnancy Report excessive bleeding,drowsiness, bone pain Avoid alcohol and gingko biloba
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)
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
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 Client teaching
◦ Routine labs; report s/s of toxicity, bleeding, pregnancy, hypoglycemia
Monitor for liver and kidney function Pregnancy category C Adverse reactions:
◦ Drowsiness, HA, euphoria, n/v, weight loss, abd. Pain
Life threatening reactions:◦ Mental depression with suicide intent◦ Blood dyscrasias and Stevens-Johnson syndrome
Symptoms of overdose◦ CNS depression, stupor, ataxia, coma
Client teaching◦ Report mood changes or suicidal thoughts◦ Avoid driving and hazardous activities◦ Take with food◦ Do not stop abruptly◦ Report weight loss and anorexia
Start with smallest dose of med Add additional drugs, if needed Monitor serum drug levels Withdrawal of meds
◦ Seizure free for three years◦ Done gradually◦ Resume meds if seizures return◦ Knowledge of rebound seizures
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
Absence/reduction in number of seizures
No injury during seizure Understanding of disease Understanding of drug regimen Compliance with lab testing
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
Objective 12 Apply nursing process as it relates to the care of the client with Parkinson’s and accompanying drug therapy.
Second most common CNS disease Progressive loss of dopamine Tremor, muscle rigidity Abnormal movement and posture
Symptoms known as parkinsonism◦ Tremors◦ Muscle rigidity◦ Bradykinesia◦ Postural instability◦ Affective flattening
Primarily affects muscle movement Patients often experience other health
issues◦ Anxiety, depression◦ Sleep disturbances◦ Dementia◦ Autonomic nervous system disturbances
Degeneration and destruction of dopamine-producing neurons◦ Substantia nigra portion of brain
Corpus striatum◦ Normally controls unconsciousness muscle
movement
Dopamine and acetylcholine in corpus striatum◦ Affect balance, posture◦ Affect muscle tone, involuntary movement
Absence of dopamine◦ Allows acetylcholine stimulation
Restore balance of dopamine and acetylcholine in brain◦ Dopaminergic drugs
Dopaminergic adjunct agents◦ Anticholinergics (cholinergic blockers)
Restore balance of dopamine and acetylcholine
Dopaminergic examples◦ Levodopa (Larodopa),◦ Levodopa and carbidopa (Sinemet)
Levodopa (Larodopa) is drug of choice◦ Increases biosynthesis of dopamine within nerve
terminals◦ Effectiveness boosted by combining with
carbidopa (Sinemet)
Inhibit enzymes◦ Example: Tolcapone (Tasmar)
Activate dopamine receptors (dopamine agonists)◦ Example: Ropinirole (Requip)
Cause dopamine release from nerve terminals◦ Example: Amantadine (Symmetrel)
Centrally acting Block acetylcholine
◦ Inhibits overactivity in brain Used in early stages Examples
◦ Benztropine mesylate (Cogentin)◦ Triexyphenidyl hydrochloride (Artane)
Reduce requirement for L-dopa Increase concentration of existing
dopamine; improve motor fluctuations Examples:
◦ entacapone (Comtan)◦ tolcapone (Tasmar)
Prototype drug: levodopa (Larodopa)• Mechanism of action: Increases
biosynthesis of dopamine within nerve terminals
Primary use: to restore dopamine function or stimulate dopamine receptors within the brain
Adverse effects: dizziness, light-headedness, sleep dysfunction, fatigue, nausea, vomiting, constipation, orthostatic hypertension, dystonia, dyskinesia
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
Contraindicated in narrow-angle glaucoma Monitor for hypotension and tachycardia Look for symptoms of drug toxicity
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
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
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)
Sedative:◦ An agent that calms nervousness, irritability
and excitement
Hypnotic◦ An agent that induces sleep
Objective 14: describe actions, use and s/e of barbiturates (covered earlier)
Objective 15: identify the commonly used barbiturates and benzo (covered earlier)
Results from damage to the motor area of the cerebral cortex
Conditions:◦ Cerebral palsy◦ severe head injury, spinal cord injury or
lesions◦ stroke◦ dystonia
Goals of muscle relaxants
◦ Minimize discomfort
◦ Increase ROM
◦ Improve ability to function independently
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
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
Assessment◦ Monitor pain, LOC, vital signs◦ Monitor muscle tone, ROM, degree of spasms◦ Monitor labs
Nursing Dx◦ Pain◦ Impaired physical mobility◦ Risk for injury◦ Deficient knowledge