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Drugs Affecting the Nervous System. Jane Bordner , Rn BSN Instructor of Nursing HACC Central Pennsylvania’s Community College Nursing 102 Fall 2012. Nervous System Review. 2 Major divisions CNS PNS. The Central and Autonomic Nervous Systems. Central nervous system (CNS) - PowerPoint PPT Presentation
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Drugs Affecting the
Nervous System
Jane Bordner, Rn BSN
Instructor of Nursing
HACC Central Pennsylvania’s
Community College
Nursing 102Fall 2012
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”
ParasympatheticNervous 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
Biochemical Response
Messenger Molecule(hormone, neurotransmitter, or drug)
Cell surface Cell surface
Sympathetic
• Major Neurotransmitters (Catecholamines) – Epinephrine– Norepinephrine– Dopamine
Effects of Sympathetic System
• 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
• Decrease heart rate• Constrict bronchial smooth
muscle• Pupil constriction• Increased GI motility• Increased secretions• Increased bladder tone
Alpha Beta
1 2 1 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 AKAADRENERGIC AGENTS
Sympathomimetics/ Adrenergic Agents
• Catecholamines• Noncatecholamines• Primary Actions
– 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– Tachycardia– Palpitations– Tremors – Hypertension– Headache– Anxiety
Adrenergic Agents
• Nursing Measures– Monitor VS frequently– Monitor breath sounds– Monitor blood glucose in Diabetic
SYMPATHOLYTICSAKAADRENERGIC 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– Antihypertensives– Vascular H/A– Raynaud’s Disease– Buerger’s Disease
Alpha Adrenergic Blocking Agents• Side Effects
– 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 lower BP
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– *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– 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
PARASYMPATHOMIMETICSAKACHOLINERGICS
Cholinergic Agents• AKA
– Parasympathomimetic
• Promotes/mimics– function of acetylcholine
• Stimulate cholinergic receptors– nicotinic and muscarinic
• Imitate parasympathetic effects
Cholinergic Agents
• Uses– 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)
PARASYMPATHOLYTICSAKACHOLINERGIC 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– 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– 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– 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
– 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– Hyperglycemia– Blood Dyscrasias– Hepatotoxicity– Rashes and pruritus
Hydantoins
• Toxicity– 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
non-compliance with drug therapy– Driving
• Must be seizure free for 6 months• Physicians required to report seizures to
DOT
Alternative Therapy
• Ketogenic Diet– 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
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