Unit 11: Drugs that affect the CNS

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Unit 11 Drugs that affect the CNS

• Nancy Pares, RN, MSN
• NURS 1950
• Metropolitan Community College

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Obj. 1 Describe the general cause of seizures
and the two major clinical findings associated
with seizures.

• 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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Obj 2 Factors that precipitate seizures

• Infectious diseases
• Trauma
• Metabolic disorders
• Vascular diseases
• Pediatric disorders
• Neoplastic diseases

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Different etiologies of seizure activity

• Most common serious neurologic problem affecting
  children
• May present as an acute situation, or they may
  occur on a chronic basis

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• Figure 15.1 EEG recordings showing the
  differences between normal, absence seizure, and
  generalized tonicclonic seizure tracings

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Drugs as cause of seizures

• High dose of local anesthetics
• Drug abuse
• Withdrawal from alcohol
• Withdrawal from sedative-hypnotics

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Convulsion

• Involuntary violent spasm of large muscles of the
  face, neck, arms and legs
• Not synonymous with seizure

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Obj. 3 Name and describe major types of
epileptic seizures

• Signs and symptoms
• Related to the area of the brain with abnormal
  activity
• Types-based on International Classification
• Partial (focal)
• Generalized
• Special epileptic syndromes

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Simple partial (focal) seizures

• 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

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Complex partial (focal) seizures

• Altered levels of consciousness
• Involve sensory, motor, autonomic symptoms
• Aura commonly precedes seizure
• No memory of seizure

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Generalized seizures

• Travel throughout the entire brain
• Subcatagories
• Absence
• Atonic
• Tonic-clonic

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Absence seizures

• Common in children
• Subtle symptoms
• Staring
• Transient loss of consciousness
• Eyelid fluttering
• Myclonic jerks

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Atonic seizures

• Usually last only a few seconds
• Characterized by stumbling or falling

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Tonic clonic

• Most common
• Usually preceded by aura
• Tonic phase
• Intense muscle contractions
• Hoarse cry at onset
• Loss of bowel/bladder control
• Shallow breathing

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Tonic clonic, cont

• Clonic phase
• Alternating contraction and relaxation of muscles
• Postictal state (post seizure)
• Drowsiness, disorientation, deep sleep

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Special epileptic syndromes

• Febrile seizures
• Myoclonic seizures
• Status epilepticus

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Febrile seizures

• 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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Myoclonic seizures

• Large jerking body movements
• Quick contraction of major muscles
• Stumbling and falling
• Similar to normal infantile Moro reflex

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Status epilepticus

• 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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Obj. 4, 5, 6,and 7 (inclusive)

• The choice of drug depends upon
• Type of seizure
• Client history and diagnostic studies
• Pathologic process causing seizures

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Once Medication is Selected

• 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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New FDA Warnings

• 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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Antiseizure Pharmacotherapy

• 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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Antiseizure Pharmacotherapy (cont'd)

• 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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Pharmacotherapy Illustrated Model of the GABA
ReceptorChloride Channel Molecules in
Relationship to Antiseizure Pharmacotherapy
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Barbiturates and GABA Agents

• GABA gamma aminobutyric acid
• Primary neuro transmitter of brain.
• Drugs that potentiate GABA action
• Barbiturates
• Benzodiazepines
• Misc. agents

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Barbiturates

• 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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Benzodiazepines

• 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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Miscellaneous GABA Agents

• Prototype valproic acid (Depakene)
• Mechanism of action
• similar to benzos and barbiturates
• Primary use
• Adjunct therapy
• Adverse effects
• Sedation, drowsiness, GI upset, prolonged
  bleeding time

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Hydantoins

• 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

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Phenytoin-like Drugs

• 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

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Succinimides

• 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

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Nurses role in pharmacological management

• 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

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Benzodiazepines-schedule IV drug

• 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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Status epilepticus

• 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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Hydantoin and Phenytoin-like drugs

• 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

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Succinimides

• 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

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Succinimides

• 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

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General client teachings for epilepsy

• 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

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Nursing diagnosis for epilepsy

• 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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Goals in epilepsy treatment

• 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
  Parkinsons Disease.
• Objective 9 Describe the role of dopamine in
  the body.
• Objective 10 name the preparations used to
  treat Parkinsons.

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• Objective 11 describe the role of the
  anticholinergic drugs in the treatment of
  Parkinsons
• Objective 12 Apply nursing process as it relates
  to the care of the client with Parkinsons and
  accompanying drug therapy.

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Parkinsons Disease

• Second most common CNS disease
• Progressive loss of dopamine
• Tremor, muscle rigidity
• Abnormal movement and posture

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Symptoms of Parkinsons Disease

• Symptoms known as parkinsonism
• Tremors
• Muscle rigidity
• Bradykinesia
• Postural instability
• Affective flattening

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Health Problems in Parkinsons Patients

• Primarily affects muscle movement
• Patients often experience other health issues
• Anxiety, depression
• Sleep disturbances
• Dementia
• Autonomic nervous system disturbances

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Cause of Symptoms

• Degeneration and destruction of
  dopamine-producing neurons
• Substantia nigra portion of brain
• Corpus striatum
• Normally controls unconsciousness muscle movement

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Neurotransmitters

• Dopamine and acetylcholine in corpus striatum
• Affect balance, posture
• Affect muscle tone, involuntary movement
• Absence of dopamine
• Allows acetylcholine stimulation

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Drug Therapy for Parkinsonism

• Restores dopamine function
• Blocks acetylcholine
• Extrapyramidal side effects (EPS)

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Antiparkinsonism Agents

• Restore balance of dopamine and acetylcholine in
  brain
• Dopaminergic drugs
• Dopaminergic adjunct agents
• Anticholinergics (cholinergic blockers)

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Dopaminergics

• Restore balance of dopamine and acetylcholine
• Dopaminergic examples
• Levodopa (Larodopa),
• Levodopa and carbidopa (Sinemet)

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Levodopa (Larodopa)

• Levodopa (Larodopa) is drug of choice
• Increases biosynthesis of dopamine within nerve
  terminals
• Effectiveness boosted by combining with carbidopa
  (Sinemet)

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Dopaminergic Adjunct Agents

• Inhibit enzymes
• Example Tolcapone (Tasmar)
• Activate dopamine receptors (dopamine agonists)
• Example Ropinirole (Requip)
• Cause dopamine release from nerve terminals
• Example Amantadine (Symmetrel)

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Anticholinergic Agents

• Centrally acting
• Block acetylcholine
• Inhibits overactivity in brain
• Used in early stages
• Examples
• Benztropine mesylate (Cogentin)
• Triexyphenidyl hydrochloride (Artane)

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Catechol-O-Methyl Transferase (COMT) Inhibitors

• Reduce requirement for L-dopa
• Increase concentration of existing dopamine
  improve motor fluctuations
• Examples
• entacapone (Comtan)
• tolcapone (Tasmar)

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Dopaminergic Agents

• 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

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Dopaminergic Agents (continued)

• Adverse effects dizziness, light-headedness,
  sleep dysfunction, fatigue, nausea, vomiting,
  constipation, orthostatic hypertension, dystonia,
  dyskinesia

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Levadopa Animation

• Click here to view an animation on the topic of
  levadopa.

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Anticholinergic Agents

• 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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Role of the Nurse Dopaminergic Drug Therapy

• Contraindicated in narrow-angle glaucoma
• Monitor for hypotension and tachycardia
• Look for symptoms of drug toxicity

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Dopaminergics Client Teaching

• 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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Anticholinergics Client Teaching

• 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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Nursing Considerations with AChE Inhibitors

• 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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Obj. 13 define sedative and hypnotic

• Sedative
• An agent that calms nervousness, irritability and
  excitement
• 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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Obj. 16 Name the conditions that may cause
muscle spasticity.

• 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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Obj. 17 Goals of drug therapy for muscle spasms

• Goals of muscle relaxants
• Minimize discomfort
• Increase ROM
• Improve ability to function independently

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Obj. 18 Name the musculoskeletal relaxants

• 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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Obj. 18 cont

• 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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Obj. 19 Nursing process for CNS drugs

• 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

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Obj. 19 cont

• Goals
• Decrease pain
• Increase range of motion (ROM)
• Reduce muscle spasms
• No adverse effects of drugs
• Knowledge of drug regimen