Transcript File

Jane Bordner, Rn
BSN
Instructor of Nursing
HACC Central
Pennsylvania’s
Community College
Nursing 102
Fall 2012
Drugs Affecting
the Nervous
System
Nervous System Review
• 2 Major divisions
– CNS
– PNS
The Central and Autonomic
Nervous Systems
• Central nervous system (CNS)
– Made up of brain and spinal cord
– Receives signals from sensory receptors
(vision, pressure, pain, cold, warmth,
touch, smell)
The Central and Autonomic
Nervous Systems
• PNS
• 2 Divisions
– Somatic- voluntary-conscious control
– Autonomic- involuntary-unconscious control
• Sympathetic- fight or flight
epinephrine/norepinephrine
• Parasympathetic- rest or digest
• acteylocholine
• 2 Types of Nerves
– Afferent – to the brain
– Efferent-from sensory organs
The Central and Autonomic
Nervous Systems (cont’d)
• Peripheral nervous system
– Afferent nerves—transmit signals to the
spinal cord and brain
– Efferent nerves—carry impulses from CNS
to other parts of body.
Autonomic Nervous System (ANS)
• 2 systems often
have opposing
functions
• Stimulate or
inhibit
• Most organ are
innervated by
both
Autonomic Nervous System
• Sympathetic - Adrenergic
• “Fight or Flight”
Sympathetic
Nervous
System
Autonomic Nervous System
• Parasympathetic - Cholinergic
• “Rest and Digest”
Parasympathetic
Nervous
System
Synapses
Neurotransmitters
1. Message travels along nerve; when it approaches nerve
ending a neurotransmitter is released
2. Neurotransmitter is received by next cell
3. Some of neurotransmitter gets reabsorbed
4. When enough neurotransmitter is received by next
nerve cell message moves forward
Messenger Molecule
(hormone, neurotransmitter, or drug)
Cell surface
Cell surface
Biochemical
Response
Sympathetic
• Major Neurotransmitters
(Catecholamines)
– Epinephrine
– Norepinephrine
– Dopamine
Effects of Sympathetic System
•
•
•
•
•
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Increase heart rate
Relax bronchial smooth muscles
Pupil dilation
Increased metabolism
Decreased GI motility
Peripheral vasoconstriction
Neuroreceptors
• Alpha 1: vasoconstriction of arterioles, relax
bladder, eyes, liver
• Alpha 2: skeletal blood vessels, pancreas
• Beta 1: AV and SA node stimulation =
increased heart rate and contraction strength
• Beta 2: relaxes smooth muscle of bronchi and
uterus
• Dopaminergic
Sympathetic Neurotransmitters
• Act on alpha, beta, or dopaminergic receptor
sites
• Example:
– Alpha 1 receptors are found in peripheral
blood vessels, when stimulated they cause
peripheral vasoconstriction which leads to
increased BP
Parasympathetic Activity
• Major Neurotransmitter (Cholinergic)
– Acetylcholine
Parasympathetic Neuroreceptors
• Cholinergic receptors
– Muscarinic
• Both excitation and inhibition
– Salivation
– Lacrimation
– Gastric acid secretion
• Slow onset
– Nicotinic
• Excitation
• Fast onset
• Short duration
Parasympathetic Effects
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•
•
•
•
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Decrease heart rate
Constrict bronchial smooth muscle
Pupil constriction
Increased GI motility
Increased secretions
Increased bladder tone
Alpha
Beta
1
1 2
2
Muscarinic
Nicotinic
Drug Effects
• Drug effect depends on:
– Specific receptor it
interacts with
– Number of receptors
– Type of receptors
– Drug specificity
• Antagonist = Block
• Agonist = Stimulate
Drug Effects
• Imitate neurotransmitters’ action
• Block neurotransmitters’ action
• Enhance or inhibit
–
–
–
–
synthesis
storage
release
breakdown
Drug Categories
• ANS drugs are categorized by
– Site of action
– Effect
– Receptor
Drug Categories
• Sympathomimetics
– Adrenergics
• Sympatholytics
– Adrenergic blockers
• Parasympathomimetics
– Cholinergics
• Parasympatholytics
– Cholinergic blockers
SYMPATHOMIMETICS AKA
ADRENERGIC AGENTS
Sympathomimetics/ Adrenergic Agents
• Catecholamines
• Noncatecholamines
• Primary Actions
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–
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Increase heart rate
Increase BP
Relax bronchial smooth muscle
Relax GI tract
Coronary artery vasodilation
Peripheral vascular vasoconstriction
Catecholamines
• Stimulate alpha and beta receptors
• Mimic action of epinephrine, norepinephrine,
and dopamine
• Examples:
–
–
–
–
dobutamine HCL (Dobutrex, Intropin, Dopastat )
Epinephrine (Adrenalin, EpiPen )
Norepinephrine (Levophed)
isoproterenol HCL (Isuprel)
Catecholamines
• Uses
– Severe hypotensive crisis
– Cardiac arrest
– Anaphylactic shock
• Special considerations
– Destroyed by digestive enzymes
“Cat”echolamines
• Side Effects
– Severe throbbing headache
– Dizziness
– Anxiety
– Fear
– Palpitations
– Hypertension
Noncatecholamines
•
•
•
•
•
•
Similar responses
More receptor selective
Slower acting
Longer lasting
Can be given PO
Usually given SC or by
inhaler
Noncatecholamines
• Examples
–
–
–
–
albuterol (Proventil)
metaproterenol sulfate (Alupent)
terbutaline (Brethine)
phenylephrine HCL (Neo-Synephrine)
• Uses
– Bronchospasm (Asthma/Emphysema)
– Nasal congestion
– Preterm labor
Bronchoconstriction
Noncatecholamines
• Side Effects
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–
–
–
–
–
Tachycardia
Palpitations
Tremors
Hypertension
Headache
Anxiety
Adrenergic Agents
• Nursing Measures
– Monitor VS frequently
– Monitor breath sounds
– Monitor blood glucose in Diabetic
SYMPATHOLYTICS
AKA
ADRENERGIC BLOCKERS
Adrenergic Blocking Agents
• AKA
– Sympatholytics
– Antiadrenergics
• Antagonistic effect
• Classified by site of action
– Alpha Adrenergic Blockers
– Beta Adrenergic Blockers
Alpha Adrenergic Blocking Agents
• Action
– Relax smooth muscle
– Peripheral vasodilation
• Uses
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–
Antihypertensives
Vascular H/A
Raynaud’s Disease
Buerger’s Disease
Alpha Adrenergic Blocking Agents
• Side Effects
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–
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Hypotension
Tachycardia
Dizziness
H/A
• Nursing Actions
– Postural BP
– Teach to avoid caffeine
Alpha Adrenergic Blocking Agents
• Examples
– ergotamine tartrate (Ergostat)
• Inhaler, PO or SL
• Treat migraine H/A
– phenoxybenzamine HCL (Dibenzyline)
• Antihypertensive
• Treat Raynaud’s Disease
– doxazosin mesylate (Cardura)
– prazosin HCL (Minipress)
– terazosin (Hytrin)
• Arteriole and venous vasodilation
BP
lower
Beta Adrenergic Blocking Agents
• AKA
– Beta Blockers
• Most widely used group
• Beta 1 receptors = heart
• Beta 2 receptors = bronchi and blood
vessels
• Mixed = Nonselective blocking agents
Beta Adrenergic Blocking Agents
• Effect
–
–
–
–
Lower HR
Decrease BP
Constrict pupil
Decrease
production of
aqueous humor
• Uses
– Cardiac
Arrhythmias
– HTN
– Angina
– Glaucoma
Beta Adrenergic Blocking Agents
• Mixed
– *labetalol (Normodyne)
• Selective Beta-1
– esmolol (Brevibloc)
– *metoprolol
(Lopressor/Toprol
XL/Betaloc )
– acebutolol (Sectral)
– betaxolol (Kerlone)
– bisoprolol (Zebeta)
– *atenolol (Tenormin)
• Non-selective Beta-1
and Beta-2
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–
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*propranolol (Inderal)
*nadolol (Corgard)
pindolol (Visken)
carteolol (Cartrol )
*sotalol (Betapace)
Timolol
(Blocadren/Timoptic )
– penbutolol (Levatol)
* Most commonly used
Beta Adrenergic Blocking Agents
• Treatment of Glaucoma
– Decrease IOP by decreasing production of
aqueous humor
• betaxolol (Betoptic)
• timolol maleate (Timoptic)
• levobunolol HCL (Betagan)
– Can cause systemic side effects
Beta Adrenergic Blocking Agents
• Side Effects
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–
–
–
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Hypotension
Bradycardia
Dizziness
Insomnia
Wheezing and Bronchospasm
Beta Adrenergic Blocking Agents
• Nursing Measures
– Never give with antacid
– Check apical pulse for one minute
before administering
– Closely monitor blood glucose in
diabetic pt.
– Teach pt. to not discontinue abruptly
PARASYMPATHOMIMETICS
AKA
CHOLINERGICS
Cholinergic Agents
• AKA
– Parasympathomimetic
• Promotes/mimics
– function of acetylcholine
• Stimulate cholinergic receptors
– nicotinic and muscarinic
• Imitate parasympathetic effects
Cholinergic Agents
• Uses
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Glaucoma
Paralytic ileus
Urinary retention
Diagnosis and treatment of Myasthenia Gravis (MG)
Antidote for tricyclic antidepressant overdose
Antidote for neuromuscular blocking agent overdose
Cholinergic Agents
• Examples
– pilocarpine HCL - treatment of glaucoma
– bethanechol (Urecholine) – treatment of urinary
retention and neurogenic bladder
– neostigmine (Prostigmin), pyridostigmine
(Mestinon) – diagnosis and treatment of MG
Cholinergic Agents
• Side Effects
–
–
–
–
–
N/V/D
Bradycardia
Hypotension
Increased salivation and sweating
Bronchoconstriction = wheezing and SOA
Cholinergic Agents
• Nursing Measures
– Never given IM or IV
– Antidote = Atropine sulfate (Cholinergic
Blocker)
PARASYMPATHOLYTICS
AKA
CHOLINERGIC BLOCKERS
Cholinergic Blocking Agents
• AKA:
– Anticholinergics
– Parasympatholytics
• Actions
– Compete with acetycholine at
muscarinic receptor sites
– antagonists
Cholinergic Blocking Agents
• Effects
–
–
–
–
Decreased GI motility
Decreased secretions
Relax bladder muscle
Increased heart rate
Cholinergic Blocking Agents
• Uses
–
–
–
–
Parkinson’s Disease
Preanesthesia Agents
Cardiac Arrhythmias
Spastic conditions of bowel and
bladder
Cholinergic Blocking Agents
• Examples
– Atropine sulfate
• Preanesthesic
• Emergency treatment of brady arrythmias
– glycopyrrolate (Robinul)
• Preanesthesic
– dicyclomine HCL (Bentyl)
• Irritable bowel syndrome
Cholinergic Blocking Agents
• Examples
– oxybutynin (Ditropan)
• Bladder spasms
– propantheline (Pro-Banthine)
• Peptic ulcer disease
– benztropine mesylate (Cogentin)
• Extrapyramidal symptoms of Parkinson’s
Cholinergic Blocking Agents
• Side Effects
– Mild
• Dry mouth
• Decreased sweating
• Decreased bronchial secretions
– Moderate
• Decreased accommodation
– Severe
• Urinary retention
• Severe constipation
• Ileus
Cholinergic Blocking Agents
• Overdose
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Restlessness
Disorientation
Hallucinations
Unconsciousness
Death
Cholinergic Blocking Agents
• Nursing Measures
– Dose range is very small
– Infants, children and elderly are more prone to
side effects
– Heatstroke is potential complication
– NEVER give to patient with glaucoma
– Used to decrease GI motility, give 30 minutes
before meals
– Watch for urinary retention
NEUROMUSCULAR BLOCKING
AGENTS
Neuromuscular Blocking Agents
• Relax skeletal muscles
– Disrupt transmission of nerve impulses at
neuromuscular junction
• Clinical Uses
– Relax muscles during surgery
– Decrease muscle spasms during ECT
– Manage ventilator patients
Neuromuscular Blocking Agents
• Examples
–
–
–
–
pancuronium bromide (Pavulon)
doxacurium Cl (Nuromax)
succinylcholine Cl (Anectine)
vecuronium bromide (Norcuron)
Neuromuscular Blocking Agents
• Side Effects
–
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–
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Excessive salivation
Excessive bronchial secretions
Bronchospasm
Apnea
Hypotension
Neuromuscular Blocking Agents
• Nursing Measures
– O2
– Suction equipment
– Artificial ventilation
AntiParkinson’s Medications
Parkinson’s Disease
• Neurotransmitters
– Dopamine ( inhibitory)
– Acetylcholine (excitatory)
• Types of parkinsoinsm
– Primary (idiopathic)
– Secondary (induced by head trauma,
infection, tumors, or drug exposure
Parkinson’s Disease
• Goal of treatment is minimization of
symptoms
• Individualized combination therapy
• Therapy begins when symptoms
interfere with the ability to function in
daily life
• All symptoms cannot be eliminated
because of side effects involved
Parkinson’s Disease
• Signs
– Facial appearance
– Psychological involvement
• Symptoms
– Motor function
• Tremor
• Dyskinesia, propulsive, uncontrolled
movement
• Bradykinesia, akinesia
• Excessive salivation
Parkinson’s Disease
Parkinson’s Disease
• Dopamine agonists
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–
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–
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Amantide hydrochloride
Bromocriptine mesylate
Carbidopa
Pergolide mesylate
Pramipexole
Ropinirole
Parkinson’s Disease
• Anticholinergic Agents
– Cogentin ( Benztropine mesylate)
– Akineton ( Biperiden hydrochloride)
– Benadryl (diphenhydramine
hydrochloride)
– Banflex, Norflex (Orphenadrine citrate)
ANTICONVULSANT
MEDICATIONS
Types of seizures
• Generalized
– Tonic-Clonic (grand mal)
– Myoclonic
– Absence (petite mal)
• Partial (localized)
– Partial simple
– Partial complex
• Status Epilepticus
Anticonvulsant Therapy (cont’d)
• Nurses may play an important role in
diagnosis and treatment
– Learn to take histories, describe seizures,
record postictal behavior
– Identify a care plan, have proper supplies,
discuss with patient and family
– Learn to assist patient during seizures,
observe and record, discuss lifestyle and
feelings with patient
Anticonvulsant Medications
• Agents
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–
–
–
–
Barbiturates
Benzodiazepines
Succinimides
Hydantoins
Miscellaneous Agents
• Action
– Increase seizure threshold
– Regulate firing by inhibiting excitation or enhancing
brains ability to inhibit its own excitation
Barbiturates
• phenobarbital (Luminal)
– Action
• Increase seizure threshold
• Prevent spread of electrical activity
– Uses
• Partial seizures
• Generalized clonic tonic seizures
Barbiturates
• Side Effects
– Sedation
– Nausea
– Lethargy
• Nursing Measures
– Monitor therapeutic blood levels
– Monitor effectiveness
– Monitor degree of sedation
Benzodiazepines
• Action
– Enhance inhibitory effect
– It is thought that they enhance the inhibitory effects of
GABA in postsynaptic clefts between nerve cells
• Drugs and Uses
– diazepam (Valium) – acute status epilepticus ;IV
– lorazepam (Ativan) – status epilepticus
– clonazepam (Klonopin) – absence and myoclonic
seizures
– clorazepate (Tranxene) – adjunct treatment of partial
seizures
Benzodiazepines
• Side Effects
–
–
–
–
Drowsiness
Confusion
Weakness
Dizziness
• Adverse Effects
– Blood dyscrasias
– Hepatotoxicity
• Nursing Measures
– Monitor CBC and LFT’s
Succinimides
• Action
– unknown
• Uses
– Absence seizures
– Petit mal
• Drugs
– ethosuximide
(Zarontin)
– Methsuximide
(Celontin)
• Side Effects
– GI upset
– Sedation
Hydantoins
• Action
– Stabilizes nerve cells against hyperexcitability
– Inhibits spread of seizure activity
• Uses
– Partial and generalized seizures
• Drugs
– phenytion (Dilantin)
– fosphenytion (Cerebyx)
– CAUTION: phenytoin (and diazepam) must be
administered slowly, and not mixed with other medications
in the same syringe
Hydantoins
• Side Effects
–
–
–
–
GI upset
Sedation
Confusion
Gingival Hyperplasia
• Adverse Effects
–
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Hyperglycemia
Blood Dyscrasias
Hepatotoxicity
Rashes and pruritus
Hydantoins
• Toxicity
–
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Nausea
Sedation
Lethargy
Nystagmus
Hydantoins
• Nursing Measures
– Monitor CBC, LFT’s, Blood Glucose and
Therapeutic Blood Levels
– Good oral hygiene
– Monitor effectiveness
– Monitor for excessive sedation
– Give with food
– Give at same time each day
MISCELLANEOUS
AGENTS
carbamzepine (Tegretol)
– Action
– Blocks up the reuptake of norepinephrine
– Decreases release of norepinephrine and rate of
dopamine and GABA turnover
– Mechanisms of action as anticonvulsant are unknown
• unknown
– Uses
• Generalized tonic-clonic seizures
• Partial and mixed seizures
• Often used with other agents
– Side Effects
• GI upset
• Sedation
• Edema
carbamazepine (Tegretol)
• Adverse Effects
–
–
–
–
–
–
–
Orthostatic hypotension
Hypertension
Dyspnea
Edema
Hepatotoxicity
Blood Dyscrasias
Rashes and pruritus
carbamazepine (Tegretol )
• Nursing Measures
– Monitor CBC, LFT’s and therapeutic blood
level
– Monitor BP
– Give with food
– Monitor seizure activity
– Monitor for excessive sedation
valproic acid (Depakote,
Depakene
– Action
• May increase concentrations of GABA
– Uses
• Absence seizures
• Combination seizures
valproic acid (Depakote,
Depakene)
• Side Effects
•
•
•
•
•
Abdominal pain
Diarrhea
Dizziness
Drowsiness
Unusual bleeding
• Nursing Measures
– CBC and platelet count before and 2 wks after
start of therapy
– LFT’s before and every 6 months
– Can cause birth defects
gabapentin (Neurotin)
• Uses
– Partial seizures
– In combination with other agents
• Side Effects
– Sedation
– Confusion
Other Miscellaneous Agents
•
•
•
•
•
•
•
lamotrigine (Lamictal)
levetiracetam (Keppra)
primidone (Mysoine)
tiagabine (Gabatril)
oxcarbazepine (Trileptal)
topiramate (Topamax)
zonisamide (Zonegran)
Anticonvulsant Medications
• General Nursing Considerations
– NEVER suddenly stop anticonvulsant therapy
– SEDATION is MOST common reason for noncompliance with drug therapy
– Driving
• Must be seizure free for 6 months
• Physicians required to report seizures to DOT
Alternative Therapy
• Ketogenic Diet
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Most successful in children
Used for intractable epilepsy
High fat, low CHO, low protein
Limited fluids
Mechanism of action unknown
Nutritional supplementation of Ca+ and vitamins
Monitor ketones with every void
May not see response for 10 wks
May gradually wean from diet after seizures controlled
Research
• GABA
– Discovered in 1950
•
•
•
•
Chemical that maintains balance in brain’s delivery system
Nerve cells communicate by releasing neurotransmitters
GABA halts messages
Without GABA, system becomes overloaded and seizures
occur
• New drug vigabatrin (Sabril ) has chemical structure similar
to GABA, ensuring GABA stays at level necessary to keep
message delivery system functioning properly