Local Anesthetics

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CNS DRUGS

• Drugs that act on the brain and / or spinal cord
• Used
• 1) Medically
• 2) Non-medically r/t their mind altering
  abilities
• Widespread use of these agents but knowledge r/t
  them is limited
• In many cultures widespread use of one or more
  CNS drugs is accepted social practice

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CNS Neurotransmitters

• More than 1 dozen compounds or transmitters
• Probably many more that have not yet been
  identified

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Blood Brain Barrier

• Distribution of drugs within the CNS is
  controlled by the BBB
• Impedes entry of drugs into the brain
• Positive benefit protection from toxic
  substances
• Negative Benefit significant obstacle in
  therapeutics

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??Therapeutic Effects

• Many drugs used in CNS disorders take time to
  develop full therapeutic effects
• Thought to be r/t time needed for adaptive
  changes in the brain to take place

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?? Side Effects

• When taken chronically, the intensity of side
  effects may decrease
• Thought to be r/t adaptive changes in the brain

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Exposure to CNS drugs tends to produce tolerance
many of these drugs cause psychological or
physical dependence

• PHYSICAL DEPENDENCE
• State in which abrupt discontinuation of drug
  will cause a withdrawal syndrome

• TOLERANCE
• Decreased response in course of prolonged drug use

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CNS stimulants are drugs that increase
behavioural activity, thought processes, and
alertness or elevate the mood of an individual.
Amphetamines, caffeine, nicotine and cocaine are
examples of these drugs. 
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CNS Stimulants

• Narcolepsy
• ADHD
• Exogenous Obesity

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Modafinil (Provigil)
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Methylphenidate (Reglan)
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ANOREXIANTS

• DEXEDRINE
• DOSPAN
• TENUATE
• FASTIN
• ACCUTRIM, DEXATRIM,PROLAMINE

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ANALEPTICS

• DOPRAM

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CAFFEINE
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HEADACHE TREATMENTS

• ERGOTS
• TRIPTANS

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Amphetamines and their related compounds are
sympathomimetic amines related to

1. epinephrine.
2. pilocarpine.
3. arecoline.
4. meperidine.

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Which of the following medications is most
commonly used for ADHD in children?

1. Methylphenidate (Ritalin)
2. Diethylpropion (Nobesine
3. Phendimetrazine (Adipost)
4. caffeine

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Amphetamines are included in the category of
drugs of abuse because of their ability to

1. cause nervousness.
2. decrease weight.
3. raise blood pressure
4. enhance performance

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Never give amphetamines in combination with

1. oral hypoglycemics.
2. insulin.
3. MAOIs
4. antihypertensives.

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CNS DEPRESSANTS

• CNS depressants are directly opposite of CNS
  stimulants which decrease behavioural activity,
  alertness and thought processes. They are often
  regarded as sedative-hypnotic compounds (drugs
  that cause relaxation), which resemble general
  anesthetics (GA) in inducing sleep but differ
  from GA in being solid or liquid (rather than
  gaseous) and in having a longer action than GA.
  Two types of CNS depressants are barbiturates and
  alcohol.

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SEDATIVES/HYPNOTICS

• PENTOTHAL ultra-short acting
• NEMBUTAL
• SECONAL
• AMYTAL - intermediate acting
• PHENOBARBITAL long acting

short acting
P
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When administering lorazepam (Ativan) IV it is
essential for the nurse to

1. monitor for symptoms of with-drawal.
2. have emergency equipment available.
3. check compatibility.
4. assess for suicidal ideation prior to
   administration

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For which of the following medical conditions
would the nurse anticipate that an antianxiety
agent would NOT be indicated?

1. Seizure disorder
2. Alcohol detoxification
3. Parkinsons disease
4. Panic disorder

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Which of the following drugs is considered to be
a sedative-hypnotic?

1. Alprazolam (Xanax)
2. Pentobarbital (Nembutal)
3. Hydroxyzine (Atarax)
4. Propranolol (Inderal)

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ANESTHETIC AGENTS
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INHALANTS
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GENERAL ANESTHETIC

• Produce unconsciousness and lack of
  responsiveness to painful stimuli
• The most poorly perfused tissues are last to
  achieve equilibrium (fat, bone, ligaments and
  cartilage)
• Concern about aspiration of gastric contents r/t
  reflexes that prevent this are abolished

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Balanced Anesthesia

• Use of combination of drugs to accomplish what
  usually cannot be achieved using inhalation
  anesthesia alone

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Two groups

• Inhalation (Ethrane, Halothane)
• Intravenous (Pentothal)

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KETAMINE

• Used a lot with children
• Will produce dissociative anesthesia
• During recovery, can have unpleasant psychologic
  reactions

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• Knowing what type of anesthetics used helps the
  PACU nurse to determine when wakefulness will
  occur

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MALIGNANT HYPERTHERMIA

• Rare, but potentially fatal reaction that can be
  triggered by all inhalation anesthetics
• Predisposition to reaction is genetically based
• Muscle rigidity and profound elevation of
  temperature

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Local Anesthetics
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Actions

• Block conduction of nerve impulses along axons
• Occurs only in those neurons located near site of
  anesthetic administration
• Affect both sensory and motor nerves
• Onset of action is usually rapid
• Used both topically and by injection

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Sequence of anesthetic effects

• Pain perception blocked first
• Followed by cold, touch and deep pressure
  sensations

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COCAINE

• Also used as a local anesthetic

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2001 ED COCAINE MENTIONS per 100,000 POPULATION
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• Local anesthetics are frequently administered in
  combination with a vasoconstrictor (epinephrine)
  to decrease blood flow to a site
• Be alert to CV reactions

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Two Groups

• 1. Esters (Procaine Novocaine )
• 2. Amides (Lidocaine Xylocaine )

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Lidocaine (Xylocaine)

• Most widely used local anesthetic
• Also used to treat dysrhythmias

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NERVE BLOCKS
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Termination of local anesthetics

• Molecules of anesthetic diffuse out of neurons
  and are carried away in the blood
• In areas where regional blood flow is high, the
  anesthetic is carried away quickly

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NON-NARCOTIC / NARCOTICANALGESICS
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Important Concepts

• Perhaps most widely prescribed drugs today - OTC
• Relatively simple class of agents
• All have same mechanism of action
• All have same basic indications
• All have same basic contraindications
• All have same basic side effects
• Gold standard is Aspirin (ASA)
• Non- addictive
• Less potent than narcotics
• Effectively treat mild to moderate pain

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Beneficial Actions

• Anti-inflammatory
• Analgesic
• Antipyretic

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Adverse Effects

• GI upset
• Ulceration
• Renal necrosis and failure
• Hepatotoxicity
• CNS effects (tinnitus, vertigo, etc.)
• Suppression of platelet aggregation

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Mechanism of Action

• Inhibition of the enzyme, Cyclooxygenase
• Cyclooxygenase is responsible for synthesis of
  prostaglandins
• Prostaglandins
• Mediate inflammatory response
• Increase responsiveness of pain receptors
• Promote fever

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Acetaminophen

• No anti-inflammatory action
• Does not suppress platelet aggregation
• No evidence linking it to Reyes syndrome
• 2 drug on CDC list for potential of causing
  overdosing toxicity
• Mucomyst is specific antidote to Acetaminophen
  toxicity
• Major toxicity is liver toxicity
• Has been reported to interact negatively with
  alcohol

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NSAIDS (Non-Steroidal Anti-Inflammatory Drugs)

• Fewer GI and hemorrhagic effects than ASA
• Still affects patients with ASA hypersensitivity
• Patients respond differently to different NSAIDs

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Formulations

• Plain
• If vinegar odor, discard
• All equal in efficacy, onset and duration
• Buffered
• Not enough buffer to make any difference
• Just as good to take plain ASA with lots of H20
• May have somewhat faster onset of action

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Formulations (cont)

• Buffered Aspirin Solution (Alka-Seltzer)
• Decreased incidence of gastric irritation
• Increased absorption
• Watch sodium content
• Enteric Coated
• Dissolve in intestine rather than stomach,
  thereby reducing gastric irritation
• Time released
• No advantage salicylic acid has a long ½ life
  anyway
• Rectal suppositories

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Therapeutic Uses

• Suppression of inflammation
• Prostaglandins mediate inflammatory responses
• Analgesia
• Prostaglandins increase responsiveness of pain
  receptors
• Reduction of fever
• Prostaglandins are in the hypothalamus, the
  region of the brain that regulates body
  temperature
• Dysmenorrhea
• Prostaglandins promote uterine contraction

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Therapeutic Uses (cont)

• Suppression of platelet aggregation
• Prevent myocardial reinfarction
• Prevention of colorectal cancer

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Adverse Effects

• GI effects
• In the stomach, prostaglandins have 3 functions
• Suppress output of gastric acid
• Promote secretion of cytoprotective mucus and
  bicarbonate
• Support normal submucosal blood flow
• NSAIDs reverse these processes, thus GI upset and
  ulceration
• Only drug approved for prophylaxis against
  aspirin induced ulcers is Misoprostol

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Adverse Effects (cont)

• Bleeding
• After just 2 aspirin, bleeding time is doubled
  for approximately 1 week
• Will intensify effects of anticoagulants
• Renal Effects
• In kidneys, prostaglandins promote vasodilation,
  thereby increasing renal blood flow
• Aspirin use causes vasoconstriction

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Adverse Effects (cont)

• Salicylism
• Tinnitus
• Sweating
• Headache
• Dizziness
• Respiratory Alkalosis
• Reyes Syndrome
• Dont give to children with viral infections
• During Pregnancy
• Is absorbed in fetal tissues and through breast
  milk

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Drug Interactions

• Warfarin
• NSAIDs will intensify effects
• Glucocorticoids
• Also cause GI upset

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Contraindications

• Aspirin sensitivity
• Nasal polyps
• Asthma
• Children with viral infections
• Congestive heart failure
• Cirrhosis
• Nephritis
• Peptic ulcer disease

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COX-2 Inhibitors

• Celebrex
• Contraindicated in patients allergic to Sulfa
  drugs
• Vioxx

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NARCOTICS
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Opioid Receptors

• Mu
• Kappa
• Delta

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Actions and Adverse Effects

• Analgesia
• Euphoria
• Sedation
• Respiratory depression
• Physical dependence
• Constipation
• Orthostatic hypertension

• Cough suppression
• Biliary colic
• Urinary retention
• Emesis
• Increased intracranial pressure
• Miosis

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Contraindications Precautions

• Convulsions
• Severe respiratory depression
• Increased intracranial pressure
• Acute asthma
• Undiagnosed acute abdominal conditions
• Decreased respiratory reserve (elderly, infants,
  respiratory disease)

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Drug Interactions

• CNS depressants
• Antipsychotics and antidepressants
• MAO inhibitors
• Neuromuscular blocking agents
• Loop diuretics

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Strong Opioid Analgesics

• Morphine
• Hydromorphine (Dilaudid)
• Meperidine (Demerol)
• Oxymorphone (Numorphan)
• Fentanyl (Sublimaze)
• Methadone (Dolophine)

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Moderate to Strong Opioid Analgesics

• Codeine
• Propoxyphene (Darvon)
• Hydrocodone
• Ultram (non-opioid)

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Agonist-Antagonist Opioid Analgesics

• Pentazocine (Talwin)
• Butophanol (Stadol)
• Nalbuphine (Nubain)
• Buprenorphine (Buprenex)

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Opioid Antagonists

• Naloxone (Narcan)
• Naltrexone
• Pure antagonists that produce no opioid effects
• Both will precipitate withdrawal

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ANTICONVULSANTS
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• Electrical disorder
• Group of disorders due to excessive neuronal
  excitability and discharge in the CNS
• Symptoms range from brief unconsciousness to
  violent, life threatening convulsions

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• SEIZURE term that applies to all epileptic
  events
• CONVULSION abnormal motor phenomenon

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Pathophysiology

• Abnormal, hyperexcitable focus
• Causes congenital defects, hypoxia at birth,
  head trauma, cancer
• Manifestations depend on location, size, and
  neuronal pathways involved

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Types of Seizures

• Partial or Focal
• Simple
• Complex
• Generalized
• Tonic Clonic (Grand Mal)
• Absence (Petit Mal)
• Status Epilepticus
• Myoclonic
• Febrile

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Treatment Rationale

• Decrease firing in focus
• Decrease spread to other areas in CNS
• Eliminate seizures with minimal disruption of
  normal function

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Diagnosis and Drug Selection

• Match drug to seizure disorder
• EEG essential
• Thorough physical, lab, and history
• Trial period needed for drug including dosage
  adjustments
• Seizure frequency chart
• Caution patients against hazardous activities

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Plasma Drug Levels

• Establish dose
• Evaluate effectiveness
• Monitor compliance

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Pregnancy and Lactation

• Balance risk of drug induced fetal injury against
  risk of injury from convulsions
• Many of these drugs interfere with Vitamin K
  metabolism
• Several of these drugs enter breast milk

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Withdrawal of Antiseizure Medications

• Some forms of epilepsy undergo spontaneous
  remission
• No firm guidelines for d/c medications
• Withdraw slowly (over 6 weeks to several months)
• If taking 2 drugs, withdraw separately, not at
  same time

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Antiseizure Medications
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Hydantoins

• Phenytoin (Dilantin)
• Peganone
• Felbatol
• Mesantoin
• Cerebyx

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Adverse Effects

• Nystagmus
• Ataxia
• Diplopia
• Gingival hyperplasia
• Morbilliform rash
• Dysrhythmias and Hypotension
• Hirsutism

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Will Increase Plasma Levels of Dilantin

• Diazepam (Valium)
• Isoniazid
• Cimetidine (Tagamet)
• Ethanol (alcohol)
• Valproic acid

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Will Decrease Plasma Levels of Dilantin

• Folic acid (Vitamin B9)
• Carbamazepine (Tegretol)
• Phenobarbital

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Barbiturates

• Phenobarbital
• Meberal
• Mysoline
• Luminal

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Adverse Effects

• CNS depression
• Drowsiness
• Agitation
• Physical dependence
• Porphyria
• Congenital abnormalities
• Interferes with metabolism of Vitamins D and K

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Succinimides

• Ethosuximide (Zarontin)
• Methsuximide (Celontin)
• Phensuximide (Milontin)

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Adverse Effects

• Drowsiness
• Dizziness
• Lethargy
• N/V

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Benzodiazepines

• Diazepam (Valium)
• Clonazepam (Klonopin)
• Clorazepate (Tranxene)
• Lorazepam (Ativan)

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Miscellaneous Anticonvulsants

• Carbamazepine (Tegretol)
• Valproic Acid (Depakene, Depakote)
• Neurontin
• Mag Sulfate

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• Teach parents with children taking antiseizure
  medications to be honest with everyone at all
  levels (day cares, school, scout troops, etc.)

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• A mother puts her name on a list for a specific
  day care when she finds out she is pregnant.
  They have no available space until the child is 4
  y.o. The child is born with epilepsy, but the
  mother doesnt tell the daycare because she is
  afraid she will lose her place. The child is
  finally accepted to the day care.

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• The mother makes the childs lunch every day and
  puts the Depakene on the childs sandwich. Two
  weeks later, the child has a seizure at the day
  care. The mother tells the daycare that she
  wasnt honest and didnt give them the childs
  full medical history.

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• The day care worker admits that she hasnt been
  fully honest either. She checked the childrens
  lunches everyday to be sure they were
  nutritionally complete. She thought the mother
  was sending moldy sandwiches and had been
  throwing them out and making the child new ones
  to avoid offending the mother.

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Drugs for Parkinsons Disease
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Pathophysiology

• Loss of Dopamine neurons in striatum
• Have to have balance between 2 neurotransmitters
  Dopamine (DA) and Acetylcholine (Ach)

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Disorder of Movement
Tremor at rest Bradykinesia Dementia
Rigidity Akinesia Depression
Postural instability Psychologic disturbances Impaired memory
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Disorder of Translation

• Know what you want to do cant make body
  cooperate

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Therapeutic Goal

• Restore DA / Ach balance by
• A) Increasing DA
• B) Decreasing Ach
• Restore patients ability to carry out ADLs

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Levodopa

• Drug of choice
• If patient does not respond to tx. - ?dx.
• Therapeutic response may take months to develop
• Tx. gt5yrs drug will lose effect

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Adverse Effects

• 1. N/V
• 2. Dyskinesias
• 3. On-Off Phenomenon
• 4. Cardiac
• 5. Psychiatric Effects
• 6. Can darken sweat and urine
• 7. Can activate malignant melanoma

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• May have to use drug holiday (10 days) to
  resume beneficial effects with long term tx.

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Drug Interactions

• (-) Pyridoxine (Vitamine B6)
• (-) Antipsychotics
• (-) MAO Inhibitors
• () Anticholinergics

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Carbidopa (Lodosyn)

• No therapeutic value by itself
• Inhibits decarboxylases in periphery
• Does not cross BBB
• Only used alone when doses of Levodopa and
  Carbidopa must be titrated seperately

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Carbidopa Levodopa (Sinemet)

• Most effective therapy for Parkinsons
• Allows for decrease in dosage
• Decreased peripheral DA side effects
• Allows for single daily dose
• May increase abnormal movements
• May increase psychiatric sx.

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Amantadine (Symmetrel)

• Antiviral agent that causes release of DA
• Responses develop rapidly but less profound
• Effects usually diminish within 3-6 months

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Adverse Effects

• Confusion, lightheadedness, anxiety
• Blurred vision, urinary retention, dry mouth,
  constipation (mimic muscarinic blockade)
• Livedo Reticularis mottled colored skin will
  subside with drug withdrawal seen in patients
  taking drug 1 month or longer

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Bromocriptine (Parlodel) and Pergolide (Permax)

• Dopamine Receptor Agonist
• Directly activates DA receptors
• Usually combined with Levodopa
• Same side effects as previous

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Selegiline (Eldepryl and Carbex)

• Inhibits MAO-B which is an enzyme that
  inactivates DA in brain
• Is NOT an antidepressant
• When used with Levodopa can
• a) delay destruction of DA made from
  Levodopa
• b) may slow progession of disease
• Usually used with newly diagnosed patients

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Centrally Acting Anticholinergic Drugs

• Block access of Ach to receptors
• May be employed alone or in combination with
  Levodopa
• Usually used in younger patients with mild
  symptoms
• Typical anticholinergic side effects
• Abrupt withdrawal can increase Parkinson symptoms

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Alternative Treatments

• Use of laser to obliterate an Ach tract until
  tremor stops
• Fetal tissue implants

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Cholinesterase Inhibitors
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• Prevent breakdown of Ach by acetylcholinesterase,
  therefore, more Ach available
• The normal job for cholinesterase is to break
  down Ach for reuptake
• Limited therapeutic value

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Reversible Cholinesterase Inhibitors

• Neostigmine (Prostigmin)
• Effects of moderate duration
• Binds to cholinesterase so Ach is not broken
  down, therefore, more Ach available

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Effects

• Increase glandular secretions
• Increase tone and motility of GI smooth muscle
• Decrease heart rate
• Contraction of smooth muscle (bronchi, bladder,
  GI tract
• Constriction of pupil
• Focusing of lens for near vision

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Main Use Myasthenia Gravis

• Autoimmune disease where patients immune system
  develops antibodies against nicotinic-M receptors
  on skeletal muscle
• Receptors are destroyed
• Muscle weakness
• Fatigue
• Ptosis
• Difficulty swallowing

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Myasthenic vs. Cholinergic Crisis

• MYASTHENIC
• Insufficient ACH available
• Extreme muscle weakness
• Tx. Neostigmine (cholinesterase inhibitor) to
  increase availability of ACh

• CHOLINERGIC
• Too much Ach in system
• Extreme muscle weakness
• Increased muscarinic symptoms
• Tx. respiratory support Atropine

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Decision Making

• Look for increase in muscarinic symptoms
• Obtain a detailed medication history
• Patients with Myasthenia Gravis should wear an ID
  tag

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Neostigmine (Prostigmin)

• Also used for reversal of non-depolarizing
  neuromuscular blockers (Tubocurarine)
• More Ach available more can compete with drug
  for binding sites at receptors
• Contraindicated for patients receiving
  Succinylcholine (depolarizing neuromuscular
  blocker)

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Phyostigmine

• Also a reversible cholinesterase inhibitor
• Different from Neostigmine because it can cross
  membranes
• Used in treatment of Atropine poisoning
• Used in treatment of glaucoma to decrease
  intraocular pressure

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Irreversible Cholinesterase Inhibitors

• DFP prototype
• HIGHLY toxic
• Found in insecticides
• Developed in World War II as nerve gas but never
  used
• Only use is for treatment of glaucoma, but better
  drugs are available

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• Highly lipid soluble absorbed from all routes
  including skin
• Binds to active center of cholinesterase
  preventing breakdown of ACh

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Symptoms

• Like cholinergic crisis
• Profuse secretions
• Involuntary urination and defecation
• Laryngospasm
• Respiratory paralysis

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Treatment

• Mechanical ventilation
• Atropine
• Protopram (specific antidote)
• must be given soon

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Drugs for Muscle Spasm and Spasticity
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OBJECTIVES

• Identify the types of drugs that can be used to
  treat localized muscle spasm.
• Discuss the treatment of spasticity.
• Differentiate between centrally acting and direct
  muscle relaxation.
• Discuss the therapeutic uses and long term
  effects of Dantrolene.

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Muscle Spasm

• Treatment
• analgesic anti-inflammatory (Aspirin)
• centrally acting muscle relaxants

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Adverse Effects of Muscle Relaxants

• CNS depression
• Warn patients about concurrent use with other CNS
  depressants
• Can produce physical dependence

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Muscle Spasticity
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Baclofen

• Acts within spinal cord to suppress reflexes
  involved in regulating muscle movement
• May mimic actions of GABA
• No direct effect on skeletal muscle
• Not effective in stroke patients
• CNS depressant
• Abrupt withdrawal causes adverse reactions
• Side effects (nausea, constipation, urinary
  retention)

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Diazepam (Valium)

• Benzodiazepine
• Acts within CNS
• No direct effect on skeletal muscle
• Sedation is common with use

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Dantrolene

• Acts directly on skeletal muscle
• Suppresses release of calcium which decreases
  ability of muscle to contract
• Same drug used to tx. malignant hyperthermia
• Adverse Effect - decreased muscle strength
• Hepatotoxic

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