Unit 11: Drugs that affect the CNS Nancy Pares, RN, MSN NURS 1950 Metropolitan Community College.

Nancy Pares, RN, MSNNURS 1950Metropolitan Community College

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

Travel throughout the entire brain

Subcatagories◦ Absence◦ Atonic◦ Tonic-clonic

Common in children Subtle symptoms

◦ Staring◦ Transient loss of consciousness◦ Eyelid fluttering◦ Myclonic jerks

Usually last only a few seconds

Characterized by stumbling or falling

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

Febrile seizures

Myoclonic seizures

Status epilepticus

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

Restores dopamine function Blocks acetylcholine Extrapyramidal side effects (EPS)

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

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

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

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