Chapter 14 Drugs Affecting - PowerPoint Presentation

Chapter 14 Drugs AffectingTheNervous System

The nervous system controls, directs and coordinates bodily functions 2 main divisions of the nervous system: Central Nervous System (CNS) - brain and spinal cordPeripheral Nervous System (PNS) - involves nerves throughout the entire body

Central Nervous System (CNS) Made up of brain and spinal cord3 main parts of brain: cerebrumcerebellumbrainstem

Cerebrum largest part of braincenter of thought and intelligencedivided into 2 halves right hemisphere controls movement and activities on bodies left sideLeft hemisphere controls right side outside of cerebrum is cerebral cortexcontrols highest functions of brain

Cerebellum regulates and coordinates body movementscontrols balance and smooth movements of voluntary musclesBrainstem connects cerebrum to spinal cordcontains: midbrain, pons, medullaspinal cord lies within spinal column conducts messages to and from brain

Brain and spinal cord are covered/protected by 3 layers of connective tissue called meningesDura mater (tough outer layer)Arachnoid (middle layer)Pia mater (inner layer) Arachnoid space: space between arachnoid and pia mater. Filled with cerebrospinal fluid Cerebrospinal fluid protects the CNS, cushions shock

Nerves carry impulses and messages to and from brain, they connect spinal cordEasily damagedTake a long time to heal Some have a myelin sheath, which is a protective covering or insulationNerves with myelin sheath conduct impulses faster Nerves

Peripheral Nervous System 12 pairs of cranial nervesConduct impulses between brain and the head, neck, chest and abdomen Conduct impulses for smell, vision, hearing, pain, touch, temperature and pressure (5 senses)Conduct impulses for voluntary and involuntary muscles 31 pairs of spinal nervesCarry impulses from skin, extremities and internal structures not supplied by cranial nerves

Autonomic Nervous System (ANS) formed by some peripheral nervescontrols involuntary muscles and certain body functions including: -heartbeat -blood pressure -intestinal contractions -glandular secretions these functions occur automaticallyANS consists of - sympathetic nervous system -parasympathetic nervous system -these systems balance each other out

Drugs Affecting the Nervous System (Delegation Guidelines)Some drugs affecting the nervous system are given parenterally by subcutaneous, intramuscular or intravenous injections You do NOT give parenteral dose formsShould a nurse delegate the administration to you REFUSE the delegation, explain why Do NOT ignore request, makes sure nurse knows you cannot give the drug and why

Drugs affecting the ANS neuron: basic nerve cell of nervous systemeach nerve is composed of a series of segments of neuronssynapse: junction between one neuron and the nextneurotransmitter: chemical substances that cause nerve signals or impulsesneurotransmitter is released into synapse at the end of a neuronreceptors on the next neuron in the chain or at the end of nerve chain are activated target organ is stimulated (ex: heart)

neurotransmitters are either -excitatory: stimulates the neuron -inhibitory: slows down, interferes or reduces chemical activitya single neuron only releases one type of neurotransmitterneurotransmitter regulation with drugs is a way to control diseases caused by an excess or deficiency of neurotransmitters

ANS controls most tissue functions (except skeletal muscle) including:blood pressure GI secretion and motilityurinary bladder functionsweatingbody tempANS maintains a constant internal environment, this is homeostasis, the ANS also responds to emergencies

ANS has 2 major neurotransmitters:norepinephrine acetylcholineAdrenergic fibers: nerve endings that release norepinephrine -drugs that cause effects like these adrenergic neurotransmitters are called: adrenergic sympathomimetic catecholamine drugs-These drugs mimic action produced by stimulation of the sympathetic nervous system. -adrenergic blocking agents: inhibit adrenergic effects

ANS neurotransmitters cont…. cholinergic fibers: nerve endings that release acetylcholine -drugs that cause effects like those produced by acetylcholine neurotransmitters are called: cholinergic parasympathomimetic -These drugs mimic action produced by stimulation of the parasympathetic nervous system - anti-cholinergic agents: drugs that block or inhibit cholinergic activity

ANS neurotransmitters cont…. most organs have both adrenergic and cholinergic fibersthese fibers produce opposite responses14-2 (p. 176-177) has the clinical uses of drugs affecting ANS

Drugs affecting the Nervous System: Adrenergic Agents:2 classes of adrenergic agents:catecholamines non-catecholamineNaturally occurring catecholamines: Norepinephrine: secreted from nerve terminalsEpinephrine: secreted from medullaDopamine: secreted at sites within brain, kidneys, GI Non-catecholamines are more selective for certain types of receptors, do NOT act as fast and have a longer duration

Adrenergic Agents cont… ANS has 3 different types of receptors. When stimulated by chemicals of certain shapes the receptors produce a certain actionAlpha-1 receptors: causes blood vessels to constrictAlpha-2 receptors: prevent further release of norepinephrine Beta-1 receptors: increase heart rateBeta-2 receptors: relax smooth muscle in bronchi ( broncho-dilation), uterus and peripheral arterial blood vessels (vaso-dilation)Dopaminergic receptors: in brain improve Parkinson's disease symptoms, in the kidneys they increase urine output because of better renal flow Many drugs act on more than one type of adrenergic receptor, each agent can only be used for a certain purpose without many adverse effects. Excess doses may cause serious adverse effects

Assisting With the Nursing Process Adrenergic Agents: ASSESSMENT: measure heart rate and BP, also see “Assisting With the Nursing Process” for respiratory tract diseases, broncho-dilators, and decongestants (Ch. 24) PLANNING: see table 14-1 (pg. 178) for “Dose Forms” IMPLEMENTATION: see table 14-1 (pg. 178) for “Action” and “Clinical Use”EVALUATION: side effects are usually dose related, report and record: - palpitations, tachycardia, skin flushing, dizziness, tremors: tend to resolve with continued therapy - orthostatic hypotension: provide for safety - dysrhythmias , chest pain, severe hypotension, hypertension, angina, nausea, vomiting: report these side effects at once

Drugs affecting the Nervous System: Alpha and Beta-Adrenergic Blocking Agents:these drugs plug the alpha or beta receptors, this prevents other agents from stimulating the receptorsThere are both selective and non-selective beta blockersNon-selective beta blockers inhibit beta-1 and beta-2 receptors Selective beta-1 blocking agents act against the hearts beta-1 receptors (cardio selective)

Alpha and Beta-Adrenergic Blocking Agents cont….. alpha receptor stimulants primary action is vaso-constriction (blood vessels constrict)therefore alpha blocking agents are used in persons with diseases associated with vaso-constrictionalpha blockers cause vaso -dilationbeta blockers often used after MI (myocardial infarction) to treat angina, dysrhythmias and hyperthyroidismbeta blockers must be used with extreme caution in those with respiratory disorders, they can produce severe broncho-constriction

Assisting With the Nursing Process Beta Blockers:ASSESSMENT: measure heart rate and rhythm, BP, see “Assisting With Nursing Process” for persons with hypertension (ch.19) anti-dysrhythmic therapy (ch. 20) PLANNING: see table 14-2 (p. 179) for “Oral Dose Forms”IMPLEMENTATION: see table 14-2 (pg.179) for “Adult Dosage Range”. Onset of action is fairly rapid, may take days/weeks for stabilization EVALUATION: most adverse effects of beta blockers are dose related, report and record: - cardiovascular: bradycardia , peripheral vasoconstriction (purple, mottled skin) - respiratory: broncho -spasm, wheezing - persons with diabetes: signs/symptoms of hypoglycemia: headache, weakness, decreased coordination, general apprehension, sweating, hunger, blurred or double vision - persons with heart failure: increase in edema, dyspnea , bradycardia , orthopnea

Drugs affecting the Nervous System: Cholinergic Agents: - cholinergic (parasympathomimetic) agents produce effects similar to acetylcholine - some cholinergic agents directly stimulate the parasympathetic nervous system - some inhibit acetylcholinesterase- the enzyme that metabolizes acetylcholine when released by a nerve ending, these agents are indirect-acting cholinergic agents

Cholinergic Agents cont….Some cholinergic actions are: - slow heart beat - increased GI motility and secretions - increased urinary bladder contractions with relaxation of muscle sphincter - increased secretions and contractility of bronchial smooth muscle - sweating - miosis of the eye (reduces intra-ocular pressure) - increased force of skeletal muscle contractions - sometimes decreased blood pressure Cholinergic agents are used to diagnose and treat myasthenia gravis

Assisting With the Nursing Process Cholinergic Agents:ASSESSMENT: measure heart rate and BP, see “Assisting With the Nursing Process” for: Respiratory diseases (ch. 24), urinary disorders (ch. 30), eye disorders (ch. 31) PLANNING: see 14-3 (pg. 180) “Oral Dose Forms”IMPLEMENTATION: see 14-3 (pg. 180) for “Clinical Use” EVALUATION: cholinergic fibers are throughout the body, most systems are affected by these drugs. All receptors do not respond to the same dosage so adverse affects are not always seen, risk for adverse affects increases with dosage report and record: - nausea, vomiting, diarrhea, abdominal cramping: dose related symptoms - dizziness, hypotension: persons BP and pulse are monitored - broncho -spasm, wheezing, bradycardia : may need to withhold dose until MD can eval

Drugs affecting the Nervous System: Anti-Cholinergic Agents:also called cholinergic blocking or parasympatholytic agentsblock action of acetylcholine in PNSdrugs occupy receptor sites at parasympathetic nerve endings, by doing this they prevent action of acetylcholine, parasympathetic response is reduced Anti-cholinergic effects:dilation of pupil with increased intra-ocular pressure (glaucoma) dry, thick secretions of mouth, nose, throat, bronchidecreased secretions/motility of GI tractincreased heart rate decreased sweating

Anti-Cholinergic Agents cont… -Anti-cholinergic effects:dilation of pupil with increased intra-ocular pressure (glaucoma)dry, thick secretions of mouth, nose, throat, bronchidecreased secretions/motility of GI tract increased heart ratedecreased sweating-Anti-cholinergic agents are used to GI and eye disorders, bradycardia, Parkinson’s disease and genito-urinary disorders-Used pre-operatively:decrease respiratory secretions to prevent aspirationsprevent vagal stimulation from skeletal muscle relaxants or placement of an endo -tracheal tube

Assisting With the Nursing Process Anti- Cholinergic Agents:ASSESSMENT: measure heart rate/BP, see “Assisting With the Nursing Process” for Drugs for Parkinson’s (p.186), persons taking antihistamines (ch. 24), persons with eye disorders (ch. 31) PLANNING: see table 14-4 (p. 180) for “Oral Dose Forms”IMPLEMENTATION: see table 14-4 (p. 180) for Clinical Use EVALUATION: cholinergic fibers are throughout the body, most systems are affected by these drugs. All receptors do not respond to the same dosage so adverse affects are not always seen, risk for adverse affects increases with dosage report and record: - blurred vision, constipation, urinary retention, dryness of mouth, nose and throat: provide safety for blurred vision. Follow care plan for constipation and urinary retention. If nurse allows provide hard candy, ice chips or gum for dry mouth - confusion, depression, nightmares, hallucinations: provide for safety - orthostatic hypotension: provide for safety. Dizziness/weakness may occur when drug is started. BP is monitored daily (supine and standing) -palpitations, dysrhythmias : tell nurse at once

Drugs affecting the Nervous System: Barbiturates: barbiturates depress the CNS, respirations, BP and temperatureacts as a sedative or hypnoticsome are used in anesthesia and to treat seizures (ch.16)CNS depression can range from mild sedation to deep coma and death. It depends on dose, route administered, tolerance from previous use, CNS excitability and person’s condition risk of addiction is high

barbiturates cont…. rarely used for sleep or sedationshort-acting barbiturates (pentobarbital, secobarbital) used for sedation before diagnostic procedureslong-acting barbiturate (phenobarbital ) used as anti- convulsant (ch. 16)

Assisting With the Nursing Process Barbiturates:ASSESSMENT: measure pulse, respiration and BP, observe persons level of alertness, ask person about pain/discomfortPLANNING: see table 14-5 (pg. 182) for “Oral Dose Forms”IMPLEMENTATION: see table 14-5 (pg. 182) for “Adult Oral Dose”. Rapidly discontinuing the drug after long-term use of high dosages may cause symptoms similar to alcohol withdrawal. Withdrawal of drug should be gradual.EVALUATION: can cause drowsiness, lethargy, headache, muscle or joint pain and mental depression. report and record the following: - hangover, sedation, lethargy: person may also have coordination issues - excitement, restlessness, confusion: provide for safety, help calm and orient the person to person, time and place - allergic reactions: report hives, itching, rash, fever or inflammation of mucous membranes at once. Do NOT give drug again until the nurse gives approval

Drugs affecting the Nervous System: Benzodiazepines:-have actions similar to CNS depressants-they act more selectively at specific sites- agents should be used no more than 4 weeks-variety of uses:sedative-hypnotic * *most common use (mild sedation) muscle relaxantanti-anxietyanti-convulsant short term use to produces sleeppre-operative sedation)

Assisting With the Nursing Process Benzodiazepines: ASSESSMENT: measure vital signs, measure BP in sitting and supine, ask person to rate their painPLANNING: see table 14-6 (pg. 183) for “Oral Dose Forms”IMPLEMENTING: see table 14-6 for Adult Oral Dose, habitual use of these drugs results In a physical and psychologic dependence. Rapidly discontinuing the drug after long-term use may cause symptoms similar to alcohol withdrawalEVALUATION: report and record the following: - confusion, agitation, hallucination, amnesia. All drugs in this class can cause these symptoms. Older persons who have taken high doses for a prolonged time are at risk - anorexia, nausea, vomiting, jaundice abnormal liver functions tests: may indicate liver toxicity

Drugs affecting the Nervous System: Non-Barbiturate, Non-Benzodiazepine Sedative-Hypnotic Agents:these drugs depress the CNSused to produce sleepdrugs in this class are used:produce mild sedationshort-term use to produce sleep examples: Benadryl, Lunesta, Ambien

Assisting With the Nursing Process Non-Barbiturate, Non-Benzodiazepine Sedative-Hypnotic Agents:ASSESSMENT: measure vital signs, BP (sitting and supine), ask person to rate their painPLANNING: see table 14-7 (p. 185) for “Dose Forms” IMPLEMENTATION: see table 14-7 (p. 185) for “Adult Oral Dose”EVALUATION: general side effects include: drowsiness, lethargy, headache, muscle or joint pain, mental depression. Dullness, moodiness and coordination problems may occur. report and record: - hangover , sedation, lethargy: may complain of “morning hangover,” blurred vision or dizziness on arising. Coordination problems: assist with walking as needed - restlessness, anxiety: usually mild - excitement, restlessness, confusion: older persons or those in severe pain may respond in ways opposite to sedation/sleep. provide for safety, help calm/orient person to person, time or place

Drugs Used for Parkinson’s Disease slow, progressive disorder, no curearea of brain that controls muscle movement is affectedpersons over age of 50 at risksigns and symptoms become worse over time, these include: -tremors: start in one finger and spread to whole arm, may have trembling in hands, arms, legs, jaw, face -rigid, stiff muscles: in arms, legs, neck, trunk -slow movements: person has slow, shuffling gait -stooped posture and impaired balance: hard to walk and at risk for falls -mask-like expression: person cannot blink and smile, fixed stare is commonother signs and symptoms develop over time (swallowing and chewing problems, constipation, bladder problems, sleep trouble, depression and emotional changes, memory loss, slow thinking, slurred, monotone or soft speech)

Drugs Used for Parkinson’s Disease cont…. symptoms are caused by a deficiency of dopaminedopamine is an inhibitory neurotransmitterwith a dopamine deficiency there is an increase in acetylcholine activityno cure for Parkinson’s disease goals of treatment: -relieve signs/symptoms -restore dopamine activity to as close to normal as possible lowest dosages possible are used, dosages increase as the disease progresses

Drugs Used for Parkinson’s Disease cont…. Promoting Safety and Comfort Drugs Used for Parkinson’s Disease:orthostatic hypotension is common with most drugs used to treat Parkinson’s disease. Safety measures are needed. remind the person to rise slowly from a supine or sitting position have person sit or lie down if they feel faint

Drugs Used for Parkinson’s Disease cont… Dopamine Agonists:agonists work on certain type of cellsproduces a predictable responsethe following dopamine agonists are used to treat Parkinson’s Disease: amantadine hydrochloride (Symmetrel)bromocriptine mesylate (Parlodel)carbidopa, levodopa , ( Sinemet and Parcopa ) pergolide mesylate ( Permax ) pramipexole ( Mirapex ) ropinirole ( Requip ) ** pgs 187-189 list the above drugs and the duties that go with assisting the nursing process**

Drugs Used for Parkinson’s Disease cont… COMT Inhibitor:COMT= catechol O-methyltransferaseCOMT is an enzyme that breaks down levodopaan inhibitor is a drug that prevents/restricts a certain actionby preventing or restricting the breakdown of levodopa the duration of levodopa is longer (levodopa replaces the dopamine deficiency in the brain) COMT inhibitor allows more dopamine to reach brain COMT inhibitors used to treat Parkinson’s: - entacapone ( Comtan , Stalevo ) ** pg. 189 lists the above drugs and the duties that go with assisting the nursing process**

Drugs Used for Parkinson’s Disease cont… Anti-Cholinergic Agents:-with Parkinson’s disease there is a deficiency of dopamine, this leaves an excess of acetylcholine-anti-cholinergic agents are used to reduce the over stimulation caused by excess amounts of acetylcholine-anti-cholinergic agents used to reduce drooling and tremors -more useful for persons with minor symptoms and not cognitive impairment-these agents have little effect on stiff/rigid muscles, slow movement and stooped posture

Drugs Used for Parkinson’s Disease cont… Assisting With the Nursing Process Anti-Cholinergic drugs:ASSESSMENT: measure vital signs, BP (sitting and supine), report persons urinary and bowel eliminations. measure pulse and note if rhythm is regular or irregular, observe persons level of alertness and orientation to person, time and place PLANNING: see table 14-8 (pg.190) for “Dose Forms”IMPLEMENTATION: see table 14-8 (pg.190) for “Adult Oral Dose” and “Maximum Daily Dose”. Give drug with food or milk to prevent stomach irritation.EVALUATION: report and record: -constipation: give stool softeners if ordered, encourage fluid intake and exercise - urinary retention: record intake/output - blurred vision: provide for safety if the person has blurred vision - dryness of mouth/throat/nose: give hard candy, ice chips or gum if nurse allows -confusion, depression, nightmares, hallucinations: provide for safety -orthostatic hypotension: see providing safety/comfort…. pg 186 -palpitations, dysrhythmias : tell nurse at once, they should inform MD

Drugs Used for Parkinson’s Disease cont… Other agents:selegiline (Eldepryl and Zelapar)reduce the destruction of dopamine in the brain, allows for more dopamine activity as parkinsons progresses it is necessary to add other drugs selegiline along with carbidopa-levodopa improves memory and allows to move faste selegiline helps slow the development of symptoms and disease progress

Drugs Used for Parkinson’s Disease cont… Assisting With the Nursing Processselegiline (Eldepryl and Zelapar):ASSESSMENT: report GI symptoms, measure BP (supine/sitting), observe persons level of alertness and orientation to person, time and placePLANNING: oral dose forms: Eldepryl : 5mg capsules, and Zelapar: 1.25mg ODTIMPLEMENTATION: dosage is adjusted to persons response and tolerance. Make sure to read how to dispense Zelapar , the tab should not be pushed through foil, used gloves, let dissolve on persons tongue. EVALUATION: report and record: - chorea, confusion and hallucinations: provide for safety - orthostatic hypotension: provide for safety (see info pg. 186)

Drugs Used for Alzheimer’s Disease (AD): AD is a brain diseasenerve cells that control intellectual and social function are damagedmemory, thinking, reasoning, judgment, language, behavior, mood and personality are affectedperson will have problems with work and everyday functions problems with family and social relationshipssteady decline in memory and mental function gradual onsetusually occurs after age of 60, risk increases with agenearly half of persons 85 and older have AD classic sign: gradual loss of short-term memory (starts as forgetfulness) disease ends in death

Drugs Used for Alzheimer’s Disease (AD) cont… 7 Stages of AD: -no impairment: no signs -very mild cognitive decline: person thinks they have memory lapses, problems not apparent to friends/family/health team -mild cognitive decline: family, friends, others notice problems. functioning in social/work settings declines -moderate cognitive decline: memory of recent or current events declines. person may withdraw in social situations -moderately severe decline: major memory problems, confusion about day or date, trouble choosing clothes to wear, knows close family and their own names, help is NOT needed with eating or elimination - severe cognitive decline: personality and behavior changes develop, person needs much help with daily activities including elimination, names forgotten but may recognize faces, sleep and incontinence problems, wandering is common -very severe decline: person cannot respond to their environment, speak or control movement. Muscles become rigid, swallowing is impaired

Drugs Used for Alzheimer’s Disease (AD) cont… donepezil (Aricept):with AD there is a loss of cholinergic neurons which results in memory loss an dementiaAricept inhibits acetylcholinesterase (the enzyme that metabolizes acetylcholine when released by a nerve ending) the drug enhances cholinergic function, effects lessen as more neurons are lostused in mild-moderate dementiagoals of therapy are to improve cognitive skills: word recall, naming objects, language, word finding, ability to do tasks

Drugs Used for Alzheimer’s Disease (AD) cont… Assisting With the Nursing Processfor Aricept:ASSESSMENT: measure vital signs, observe cognitive functions, observe for GI symptomsPLANNING: oral dose forms: 5 and 10 mg tabs as well as 5 and 10mg orally disintegrating tabs IMPLEMENTATION: initial dose: 5mg at bedtime, after 4-6 weeks dosage may be increased to 10mg. Drug can be given with or without foodEVALUATION: report and record: -nausea, vomiting, indigestion, diarrhea. symptoms less with lower doses, tend to subside after a few weeks -bradycardia: tell nurse at once if persons pulse is less than 60 beats/min

Drugs Used for Alzheimer’s Disease (AD) cont… memantine (Namenda): - blocks a receptor in CNS that is activated in AD - drug can be used alone or with others - treats moderate-severe AD -cognitive function and behaviors are improvedAssisting With the Nursing Processfor Namenda: ASSESSMENT: measure vital signs, observe cognitive functionsPLANNING: oral dose forms: 5 and 10 mg tabs IMPLEMENTATION: initial dose: 5mg once/day, can be increased by 5mg every 7days to 10/15/20mg daily EVALUATION: report and record: -headache, dizziness, insomnia, restlessness, increased motor activity, excitement, agitation. Tend to decline with continued therapy

Drugs Used for Alzheimer’s Disease (AD) cont… galantamine (Razadyne): - prevents breakdown of acetylcholine - used to treat mild-moderate symptoms of AD Assisting With the Nursing Processfor Razadyne:ASSESSMENT: measure vital signs and weight, observe cognitive functions PLANNING: oral dose forms: 4, 8, 12mg tablets and 16, 24mg extended release capsulesIMPLEMENTATION: initial dose: 4mg 2x/daily, after 4 weeks dose increased to 8mg 2x/day, after another 4 weeks dose increased to 12mg 2x/day. Drug given with food. EVALUATION: report and record: -nausea, vomiting, diarrhea, weight loss

Drugs Used for Alzheimer’s Disease (AD) cont… rivastigmine (Exelon): - prevents breakdown of acetylcholine - used to treat mild-moderate AD symptomsAssisting With the Nursing Processfor Exelon: ASSESSMENT: measure vital signs and weight, observe cognitive functions and for muscle weaknessPLANNING: oral dose forms: 1.5, 3, 4.5, 6mg capsules transdermal patch: 4.6mg/24 hours or 9.5mg/24 hoursIMPLEMENTATION: initial dose is for 4 weeks: oral: 1.5mg 2x/day with food patch: 4.6mg once/day (after 4 weeks 9.5mg patch once/day) after 4 weeks oral dose is increased by 1.5mg 2x/day every 2 weeks. Usual maintenance dose is 3-6mg 2x/day EVALUATION: report and record: -nausea, vomiting, weight loss, GI upset, muscle weakness