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Central Nervous System Depressants
CNS Depressants SedativesDrugs that have an inhibitory effect on the CNS to the degree that they reduce:NervousnessExcitabilityIrritabilitywithout causing sleep
CNS Depressants HypnoticsCalm or soothe the CNS to the point that they cause sleep
CNS DepressantsSedative-Hypnoticsdose dependent:At low doses, calm or soothe the CNS without inducing sleepAt high doses, calm or soothe the CNSto the point of causing sleep
Sedative-Hypnotics: BarbituratesFirst introduced in 1903, standard agents for insomnia and sedationHabit-formingOnly a handful commonly used today due in part to the safety and efficacy of: BENZODIAZEPINES
Sedative-Hypnotics: BarbituratesFour categories:Ultrashortmephobexital, thiamylal, thiopentalShortpentobarbital, secobarbitalIntermediateaprobarbital, butabarbitalLongphenobarbital
Sedative-Hypnotics: BarbituratesBarbiturates have a very narrow therapeutic index. Therapeutic IndexDosage range within which the drug is effective but above which is rapidly toxic.
Sedative-Hypnotics: BarbituratesMechanism of ActionSite of action:Brain stem (reticular formation)Cerebral cortexBy inhibiting GABA, nerve impulses traveling in the cerebral cortex are also inhibited.
Sedative-Hypnotics: BarbituratesDrug EffectsLow doses:Sedative effects
High doses:Hypnotic effects (also lowers respiratory rate) Notorious enzyme inducers
Sedative-Hypnotics: BarbituratesTherapeutic UsesHypnoticsSedativesAnticonvulsantsSurgical procedures
Sedative-Hypnotics: BarbituratesSide EffectsBody SystemEffectsCNSDrowsiness, lethargy, vertigomental depression, coma RespiratoryRespiratory depression, apnea, bronchospasms, cough
Sedative-Hypnotics: BarbituratesSide EffectsBody SystemEffectsGINausea, vomiting, diarrhea OtherAgranulocytosis, vasodilation, hypotension, Stevens-Johnson syndrome
Sedative-Hypnotics: BarbituratesToxicologyOverdose frequently leads to respiratory depression, and subsequently, respiratory arrest.Can be therapeutic:Anesthesia inductionUncontrollable seizures: phenobarbital coma
Sedative-Hypnotics: BarbituratesDrug InteractionsAdditive effects:ETOH, antihistamines, benzodiazepines, narcotics, tranquilizersInhibited metabolism:MAOIs will prolong effects of barbituratesIncreased metabolism:Reduces anticoagulant response, leading to possible clot formation
CNS Depressants: BenzodiazepinesMost frequently prescribed sedative-hypnoticsMost commonly prescribed drug classesFavorable side effectsEfficacySafety
CNS Depressants: BenzodiazepinesClassified as either:Sedative-hypnotic or Anxiolytic (Medication that relieves anxiety)
CNS Depressants: BenzodiazepinesSedative-Hypnotic TypeLong-Acting:flurazepam (Dalmane), quazepam (Doral) Short-Acting:estazolam (Prosom), temazepam (Restoril),triazolam (Halcion)
CNS Depressants: BenzodiazepinesAnxiolytic Typealprazolam (Xanax)chloridiazepoxide (Librium)diazepam (Valium)lorazepam (Ativan)midazolam (Versed) zolpidem (Ambien) and zaleplon (Sonata)(nonbenzodiazepine hypnotic agents, share characteristics)
CNS Depressants: BenzodiazepinesMechanism of ActionDepress CNS activityAffect hypothalamic, thalamic, and limbic systems of the brainBenzodiazepine receptors
CNS Depressants: BenzodiazepinesDrug EffectsCalming effect on the CNSUseful in controlling agitation and anxiety
CNS Depressants: BenzodiazepinesTherapeutic UsesSedationSleep inductionSkeletal muscle relaxationAnxiety reliefTreatment of alcohol withdrawalAgitationDepressionEpilepsyBalanced anesthesia
CNS Depressants: BenzodiazepinesSide EffectsMild and infrequentHeadacheDrowsinessDizzinessVertigoLethargyParadoxical excitement (nervousness) Hangover effect
CNS Depressants: Nursing ImplicationsBefore beginning therapy, perform a thorough history regarding allergies, use of other medications,health history, and medical history.Obtain baseline vital signs and I & O, including supine and erect BPs.Assess for potential disorders or conditions that may be contraindications, and for potential drug interactions.
CNS Depressants: Nursing ImplicationsGive 15 to 30 minutes before bedtime for maximum effectiveness in inducing sleep.Most benzodiazepines (except flurazepam) cause REM rebound and a tired feeling the next day; use with caution in the elderly.Patients should be instructed to avoid alcohol and other CNS depressants.
CNS Depressants: Nursing ImplicationsCheck with physician before taking any other medications, including OTC medications.It may take 2 to 3 weeks to notice improved sleep when taking barbiturates.Abruptly stopping these medications, especially barbiturates, may cause rebound insomnia.
CNS Depressants: Nursing ImplicationsSafety is importantKeep side rails upDo not permit smokingAssist patient with ambulation (especially the elderly)Keep call light within reachMonitor for side effects
CNS Depressants: Nursing ImplicationsMonitor for therapeutic effectsIncreased ability to sleep at nightFewer awakeningsShorter sleep induction timeFew side effects, such as hangover effectsImproved sense of well-being because of improved sleep
Anticonvulsants and Drugs to Treat Other CNS Disorders
Chapter 8 TopicsEpilepsyParkinsons DiseaseMyasthenia GravisAttention-Deficit DisordersAmyotrophic Lateral Sclerosis (ALS)Multiple Sclerosis (MS)Alzheimers Disease
Learning ObjectivesDevelop an understanding of the physiologic processes that occur in epilepsy.Classify seizures and the goals of their therapy.Understand that specific drugs are used in different classes of seizures.
Learning ObjectivesBe familiar with Parkinsons disease and the drugs used in its treatment.Know the symptoms and treatments ofmyasthenia gravisattention-deficit disordersamyotrophic lateral sclerosismultiple sclerosisAlzheimers disease
EpilepsyCommon neurologic disorder with sudden and recurring seizuresCaused by abnormal electrical impulses in the brain
EpilepsyIn the U.S., 2.5 million people are affected.
Not all seizure disorders are epilepsy.
EpilepsySeizureAbnormal electrical discharges in the cerebral cortex caused by sudden, excessive firing of neuronsResult in a change in behavior of which the patient is not awareWhile conscious, the patient may or may not lose movement controlLoss of body control may affect one area or the entire body
EpilepsyCauses of Seizures Imbalance of excitatory and inhibitory neurotransmitters:Glutamate inhibitoryGABA excitatoryOther neurotransmitters can be involvedNeurotransmitter levels are controlled by enzymesDisruption in enzymes = disruption of neurotransmitters
EpilepsyCauses of SeizuresETOH withdrawalCardiovascular diseaseHigh feverHypocalcemiaHigh or low blood sugarHypoxia
Infection (meningitis)Metabolic abnormalitiesBrain tumorToxic substancesTrauma or injury to the head
EpilepsyClasses of SeizuresPartialGeneralized
EpilepsyClasses of SeizuresPartialSimple-partialComplex-partialGeneralized
EpilepsyClasses of SeizuresPartialSimple-partialComplex-partialGeneralizedTonic-clonic or grand malAbsence or petit malMyoclonicAtonic
EpilepsyPartial SeizuresLocalized in a specific area of the brainOccurs with 65% of epileptic patientsCan progress to generalized seizures
EpilepsyPartial SeizuresSimple-PartialComplex-Partial
EpilepsyPartial SeizuresSimple-PartialNo loss of consciousnessMay have muscle twitching or sensory hallucinationsComplex-Partial
EpilepsyPartial SeizuresSimple-PartialNo loss of consciousnessMay have muscle twitching or sensory hallucinationsComplex-PartialImpaired consciousnessWith confusion, blank stare, and postseizure amnesia
EpilepsyGeneralized SeizuresInvolves both hemispheres of the brain, not one specific locationTypesTonic-ClonicAbsenseMyoclonicAtonic
Generalized SeizuresTonic-Clonic SeizuresTonic body becomes rigid, lasts a minute or lessClonic initiated with muscle jerks, and may be accompanied by shallow breathing, loss of bladder control, and excess salivation
Generalized SeizuresAbsenceInterruption of activities by blank stare, rotating eyes, uncontrolled facial movements, rapid eye blinking, and/or jerking of an arm or legNo generalized convulsionsUsually lasts 30 seconds or lessMany times it progresses to tonic-clonic as the patient gets older
Generalized SeizuresMyoclonicOccurs with sudden, massive, brief muscle jerks or non-massive, quick jerksConsciousness is not lostCan occur during sleep
Generalized SeizuresAtonicBegins with sudden loss of muscle tone and consciousnessMuscles relax, limbs go limpLasts a few seconds to a minute, then patient can resume standing and walking
Generalized SeizuresStatus EpilepticusContinuous tonic-clonic seizures with or without return to consciousnessHigh fever and lack of oxygen severe enough to cause brain damage or death
DiscussionWhat percentage of status epilepticus patients die, regardless of treatment?
DiscussionWhat percentage of patients status epilepticus patients die, regardless of treatment?
Answer: 10%
Antiepileptic Drug TherapyGoals of TherapySeizure control or lessen the frequencyPrevent emotional and behavioral changes
DiscussionNote: 30% of patients are not compliant due to side effects (sedation and loss of cognitive processes).
What are some possible strategies health care providers can use to help improve drug therapy compliance?
Antiepileptic Drug TherapyNeuronal ActivityPolarized (resting)Depolarized (firing)Sodium and calcium enter the cellWhen sufficient amounts cross, neurotransmitters are releasedNeurotransmitter release leads to firing of the neuronRepolarization (return to resting)
Antiepileptic Drug TherapyAbnormal Neuronal ActivityDepolarizationIf excessive neurotransmitters are released it leads to uncontrollable firing of the neuron = seizureTreatmentBlock the firing of the neuron by raising the threshold of depolarization
Antiepileptic Drug TherapyStart with monotherapy at a low dose and titrate up slowlyMedication must be maintained at steady therapeutic levels (no missed doses)Polytherapy can be used if sufficient response is not seen with monotherapy
Antiepileptic Drug TherapyProblems with TherapyWrong medication is used for the seizure typeSide effects may cause problems with patient complianceIf doses are missed, there is an increased risk of seizure activity
Anticonvulsantscarbamazepine (Epitol, Tegretol)clonazepam (Klonopin)diazepam (Valium)divalproex (Depakote)ethosuximide (Zarontin)Fosphyenytoin (Cerebyx) gabapentin (Neurontin)Drug List
Anticonvulsantslamotrigine (Lamictal)levetiracetam (Keppra)lorazepam (Ativan)oxcarbazepine (Trileptal)phenobarbital (Luminal Sodium)phenytoin (Dilantin)Drug List
Anticonvulsantsprimidone (Mysoline)topiramate (Topamax)valproic acid (Depakene)zonisamide (Zonegran)Drug List
Therapeutic Regimens for Seizures
Therapeutic Regimens for Seizures
valproic acid (Depakene) and divalproex (Depakote)Increases the availability of GABA (inhibitory)Take with water, not a carbonated drinkDo not use aspirin
Dispensing IssuesDepakote and Depakene can easily be confused.Be careful with Depakote and Depakote ER.Depakote ER is only once a day.Warning!
phenytoin (Dilantin)May be used to prevent seizuresPromotes sodium outflow from cells stabilizes the neuronal membraneBe cautious of drug interactionsIntravenous phenytoin must be mixed carefully
Phenytoin Side EffectsDose RelatedAtaxiaDiplopiaDizzinessDrowsinessEncephalopathyInvoluntary movements
Phenytoin Side EffectsNon-Dose-RelatedGingival hyperplasiaPeripheral neuropathyVitamin deficiencies
Dispensing IssuesLook-Alike and Sound-Alike DrugsCerebyx (anticonvulsant)Celexa (antidepressant)Celebrex (for pain and arthritis)Warning!
carbamazepine (Epitol, Tegretol)Has effect on sodium channels which may alter synaptic transmission.Blood monitoring must be done regularly.Be cautious of interactions and side effects.
gabapentin (Neurontin)Used in conjunction with other medicationsNo significant drug interactionsUsed for many other disorders, particularly neuropathic pain
Dispensing IssuesNeurontin (anticonvulsant) and Noroxin (antibiotic) are sound-alike drugs, but they are easy to distinguish by strength.Warning!
clonazepam (Klonopin)Only indication is prophylaxis of seizuresDepresses nerve transmission in the motor cortexC-IV controlled substance (benzodiazepine)
Dispensing IssuesLook-Alike and Sound-Alike DrugsLamictal (anticonvulsant)Lamisil (antifungal)Lomotil (for diarrhea)Warning!
topiramate (Topamax)Is thought to alter sodium channels and thereby increases GABA activity and decreases glutamine activity Causes significant cognitive effectsDrink fluids to decrease risk of kidney stones
Dispensing IssuesLook-Alike and Sound-Alike DrugsKaletra (antiviral for HIV)Keflex (antibiotic)Keppra (anticonvulsant)Warning!
DiscussionWhich neurotransmitters play the greatest role in seizures?
DiscussionWhich neurotransmitters play the greatest role in seizures?
Answer Glutamate (excitatory) GABA (inhibitory)
Parkinsons DiseaseCharacteristic SignsResting tremorRigidityAkinesiaUsually affects people over 60
Parkinsons DiseasePhysiologyResult of pathologic alterations in the extrapyramidal system (part of the CNS that controls motor activities)Distinguishing feature: Lewy bodies (protein masses) found in the midbrain
Parkinsons DiseasePhysiologyNormal muscle movement requires balance of dopamine (inhibitor) and ACh (stimulator)In the substantia nigra, enough dopamine is released to counteract the effects of AChIn parkinsonism, enough dopamine is not released which leads to excessive motor nerve stimulation
Cutaway View of the Brain
Substantia Nigra
Parkinsons DiseaseDrug TherapyImproves the functional ability and clinical status of patientsAims at symptomatic relief, does not alter the disease processPatients may have temporary or prolonged remissionSide effects can be a problem
Anti-Parkinson Agentsamantadine (Symmetrel)benztropine (Cogentin)bromocriptine (Parlodel)entacapone (Comtan)levodopa (Dopar)levodopa-carbidopa (Sinemet)Drug List
Anti-Parkinson Agentslevodopa-carbidopa-entacapone (Stalevo)pergolide (Permax)pramipexole (Mirapex)ropinirole (ReQuip)selegiline (Eldepryl)tolcapone (Tasmar)Drug List
levodopa (Dopar)Metabolized to dopamine in the brain, but the brain does not receive a full doseDrug has very undesirable effectsAfter about 5 years of therapy, 2/3 of patients experience on-off phenomenon
levodopa-carbidopa (Sinemet)Probably the most common drug used for parkinsonismCarbidopa allows for lower doses of levodopa to be used which decreases side effects
Dispensing IssuesLook-Alike and Sound-Alike DrugsAmantadine (for Parkinsons)Ranitidine (for the stomach)Rimantadine (for the flu)Warning!
entacapone (Comtan)Indicated for patients who have a deteriorating response to levodopaLess toxic than tolcaponeTake without regard to food
DiscussionWhat are the two primary neurotransmitters involved in Parkinsons disease and what role do they play?
DiscussionWhat are the two primary neurotransmitters involved in Parkinsons disease and what role do they play?
Answer ACh (excitatory) Dopamine (inhibitory)
Myasthenia GravisAutoimmune disorder of the neuromuscular junctionACh receptors are destroyed at the motor end plateCharacterized by weakness and fatigability, especially of the skeletal muscles
Motor End Plate
Myasthenia GravisPresenting SignsPtosis (drooping eyelid)Diplopia (double vision)Dyarthria (speech)Dysphagia (swallowing)
Myasthenia GravisTreatmentBlocking the destruction of ACh causes improvement for the patient
Myasthenia Gravis Agentsazathioprine (Imuran)cyclophosphamide (Cytoxan)edrophonium (Enlon, Reversol)neostigmine (Prostigmin)pyridostigmine (Mestinon)Drug List
pyridostigmine (Mestinon)Blocks destruction of ACh Allows for ACh accumulation at the synaptic junction
cyclophosphamide (Cytoxan)Prevents cell division by targeting the auto-immune portion of the diseaseUse chemotherapeutic precautions
Attention-Deficit DisordersAttention-Deficit Hyperactivity Disorder (ADHD)Attention-Deficit Disorder (ADD)
Attention-Deficit DisordersAttention-Deficit Hyperactivity Disorder (ADHD)Characterized by purposeless, chronic, pervasive, driven behavior that affects a child in social, emotional, and academic settings.
Attention-Deficit DisordersAttention-Deficit Hyperactivity Disorder (ADHD)Characteristics for AssessmentHyperactivityImpulsivityDistractibility
Attention-Deficit DisordersAttention-Deficit Disorder (ADD)Has less hyperactivityChild is more lethargic and more easily distractedBoth disorders are more common in boys than girlsSome symptoms can persist into adulthood
Attention-Deficit Disorder Agentsatomoxetine (Strattera)clonidine (Catapres, Catapres-TTS)desipramine (Norpramin)dexmethylphenidate (Focalin), C-IIdextroamphetamine-amphetamine (Adderall), C-IIDrug List
Attention-Deficit Disorder Agentsimipramine (Tofranil)methylphenidate (Concerta, Metadate, Ritalin, Ritalin-SR), C-IInortriptyline (Aventyl, Pamelor)pemoline (Cylert), C-IVDrug List
methylphenidate (Concerta, Metadate, Ritalin, Ritalin-SR)C-II controlled substanceDrug of choice to treat ADD, ADHD, and narcolepsyIncreases levels of neurotransmitters in the brainConcerta is a QD dose outer shell dissolves to release medication immediately, then drug is slowly released through pores in the tablet
dextroamphetamine-amphetamine (Adderall)C-II controlled substanceEffects last about 6 hoursPrimary side effect is depression
Dispensing IssuesLook-Alike and Sound-Alike DrugsAdderall (ADD, ADHD)Inderal (anxiety, hypertension)Warning!
atomoxetine (Strattera)Nonstimulant inhibitor of norepinephrine reuptakeControls impulsivity and activityNot a controlled substance, so refills can be called inSide effects: weight loss and slowed growth
Dispensing IssuesLook-Alike and Sound-Alike DrugsClonidine (ADD, ADHD)Klonopin (seizures)Warning!
DiscussionCompare and contrast ADHD and ADD.
DiscussionCompare and contrast ADHD and ADD.
AnswerADHD hyperactivity, impulsivity, and distractabilityADD more lethargic and easily distracted
Amyotrophic Lateral Sclerosis (ALS)Known as Lou Gehrigs diseaseProgressive degenerative disease of the nervesLeads to muscle weakness, paralysis, and eventually deathCaused by excessive levels of glutamate
ALS Agentriluzole (Rilutek)Drug List
riluzole (Rilutek)First drug approved for ALSInhibits release of glutamateShown to improve survival rate by 3 months is some patients
Multiple Sclerosis (MS)Autoimmune disease in which myelin sheaths degeneratePatient loses use of muscles and often eyesight is affectedSome drugs can slow progression, but there is no cure
MS Agentsbaclofen (Lioresal)glatiramer acetate (Copaxone)interferon beta-1a (Avonex, Rebif)interferon beta-1b (Betaseron)mitoxantrone (Novantrone)tizanidine (Zanaflex)Drug List
interferon beta-1a (Avonex, Rebif)Used for ambulatory patientsReduces frequency of attacksDelays disabilityDrug should be taken at night with APAP to prevent flu-like side effects
baclofen (Lioresal)Skeletal muscle relaxantInhibits transmission of reflexes at the spinal cordOnset requires three to four days
Alzheimers DiseaseDegenerative disorder of the brain that leads to progressive dementia and changes in personality and behaviorProgressionMinor forgetfulnessInability to complete complex tasksComplete incapacitation, disorientation, and failure to thrive
Alzheimers DiseaseThere are no treatments that can reverse this disease
Depression should be treated according to symptoms
Alzheimers Agentsdonepezil (Aricept)galantamine (Reminyl)ginkgo memantine (Namenda)rivastigmine (Exelon)tacrine (Cognex)Drug List
donepezil (Aricept)Convenient with few side effectsImproves memory and alertnessGive once a day at bedtime
memantine (Namenda)May have fewer side effects than other drugsApproved for moderate to severe conditionsEvidence that the drug does slow disease
rivastigmine (Exelon)Has fewer interactions than AriceptMore difficult to dose and administer
DiscussionHow does Alzheimers disease affect patients families? Has the disease affected someone in your family?
DiscussionSeveral of the diseases presented in this chapter are degenerative and there is yet no known cure. How might this affect patients with a diagnosis of one of these conditions?