Central Nervous System Flashcards

1
Q

Epilepsy definition

A

Chronic disorder characterized by seizures that usually recur unpredictably and in absence of any consistent provoking factors

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2
Q

Epilepsy stats and causes

A

World wide prevalence of about 1%. 70% of which are one type of seizure
Most primary causes are idiopathic (unknown)
Some secondary causes include neoplasms, cerebral infections, high fever, trauma, metabolic disorders and withdrawal symptoms

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3
Q

Types of seizures

A
  1. simple/partial seizures (apporx, 70-80% of all)
    - 20-60 seconds in length
    - no impaired consciousness
  2. Complex/partial seizures
    - 45-90 seconds on length
    - impaired consciousness, lack of responsiveness
    - tonic, clonic, or tonic-clonic seizures (thrashing)
  3. Generalized seizures - head drop, staring off into space
    - temporary lapse in consciousness lasting a few seconds
    - most often seen in children
    - may have several attacks per day
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4
Q

Principles of drug therapy for seizures

A

50% will achieve complete control with drug therapy
25% will have reduced frequency of the seizures
Two or more unprovoked seizures with in 6 to 12 months will initiate therapy, and to discontinue therapy you need to be seizure free for at least two years

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5
Q

List the common seizure drug therapy

A
Phenytoin
 Carbamazepine
 Valproic acid (divalproex)
 Benzodiazepines
 Gabapentin
 Topiramate
 Phenobarbital
 Lamotrigine
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6
Q

What do antiepileptic medications and drugs do

A
  • Seizures occur when there is an imbalance within excitatory and inhibitory circuits in the brain
  • antiepileptic drugs work in different ways to prevent seizures either by decreasing excitation or enhancing inhibition
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7
Q

Phenytoin (antiepileptic) mechanism of action and uses

A

Also known as Dilantin

  • stabilizes neurons against hyperexcitability through sodium channels
  • generalized (tonic-clonic) and partial seizures (complex/simple)
  • not effective for absence seizures
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8
Q

Phenytoin dose, dosage forms and strengths

A

Dose: 300-400 mg/day. Need a blood test to determine how much is in the blood. Doses over 400mg should be given BID
forms and strengths: injectible (IV only) and Oral
IM or SC lead to erratic absorption and extravasation at injection site

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9
Q

Phenytoin adverse effects

A

CNS - drowsiness, confusion (toxicity = ataxia, nystagmus)
GI - nausea, vomiting
Dermatological - skin rash, gingival hyperplasia (thick gums), extravasation
Other - hirsutism

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10
Q

Patient focus with phenytoin

A
  • monitor for a serious adverse reactions
  • reinforce importance of good dental hygiene
  • do not abruptly stop this medication and do not use with alcohol
  • separate enteral feeds by 1 to 2 hours before and after giving phenytoin
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11
Q

Carbamazepine uses

A

Carbamazepine affects sodium channels, and inhibits rapid firing of brain cells
USES: Generalized (tonic/clonic), Partial (simple&complex). Other uses include trigeminal neuralgia, bipolar disorder

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12
Q

Carbamazepine dose

A

800 to 1200 mg/day

  • regular release tablets and two tabs for children (BID-QID)
  • no injectable form available
  • blood test to measure drive in body
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13
Q

Carbamazepine adverse effects

A

CNS - dizziness, ataxia, diplopia (double vision) nausea, vomiting, anorexia
Metabolic - hyponatremia (in elderly)
Hematologic - Low blood count = suppressed immune system = can’t fight infection)
Dermatological - rash

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14
Q

Valproic acid / Divalproex mechanism of action and uses

A
  • mechanism of action is unknown, but thought to be related to increased levels of GABA
    Uses - Generalized (absence seizures), Partial (simple & complex seizures. Also used for migraine prophylaxis and bipolar disorder
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15
Q

Valproic acid / Divalproex Dose

A
  • need a blood test to determine how much in the body
  • Target drug levels 350 to 700mmol/L
  • take with food swallowed whole, do not crush or chew capsules or tablets
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16
Q

Valproic acid / Divalproex adverse effects

A

CNS - tremor, ataxia, diplopia, lethargy, drowsiness and behavioural changes
GI - nausea, vomiting, enteric coated tablets will decrease this affect
Dermatological - alopecia
Hepatic - can damage over time and tests will need to be done

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17
Q

Benzodiazepines mechanism of action and uses

A

The ‘PAM’ family of drugs
Mechanism of action: enhances and inhibitory neurotransmitter called GABA
Uses: Status epilepticus (seizure that doesn’t stop), myoclonus, and absence (other uses: anxiolytic, sedative)

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18
Q

Benzodiazepine adverse effects

A

CNS - drowsiness, dizziness, ataxia, disorientation. (excitation, agitation in elderly and young). Anterograde amnesia
Respiratory: respiratory depression which can lead to falls risk with elderly

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19
Q

Gabapentin for seizures

A

Used primarily for partial seizures (and neuropathic pain)

Adverse effects; dizziness, drowsiness, nystagmus, weight gain

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20
Q

Topiramate for seizures

A

Used for as adjunct (add-on) for partial seizures
Also use for migraines and bipolar disorder
Adverse effects: drowsiness, nystagmus

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21
Q

Phenobarbital for seizures

A

Used for Febrile (high temp) seizures.
generalized and partial seizures
Adverse effects: lethargy, dizziness, drowsiness, hypotension, bradycardia

22
Q

Lamotrigine for seizures

A

Used for partial seizures

Increase dose slowly due to risk of rash

23
Q

What is Parkinson’s disease and what are its characteristics

A
  • Parkinson’s disease is a degenerative disorder of the central nervous system that effects motor skills and speech
  • it is characterized by muscle rigidity, tremor, and a slowing of physical movement (bradykinesia)
  • Parkinson’s disease is both chronic and progressive it affects 1% of the population over 50 years old
24
Q

Drug-induced Parkinson’s disease

A

Antipsychotics, what are used to treat schizophrenia and psychosis, can induce the symptoms of Parkinson’s disease by lowering dopaminergic activity

25
Symptoms of parkinson's disease (TRAP)
Tremor - resting tremor Rigidity - ratchet-like movement, cogwheel rigidity, masking Akinesia/Bradykinesia - absence/slowness in movement Postural instability - impaired balance/coordination, shuffle
26
Parkinson's disease principles of drug therapy and pharmacotherapy
- alleviate the signs and symptoms as there is no cure - improve overall quality of life and physical functioning - minimize adverse drug affects Pharmacotherapy: -Levodopa/Carbidopa -COMT inhibitors -Selegiline -Dopamine agonists -anticholinergics -amantadine in advanced stages, surgery is an option
27
Levodopa/Carbidopa (Sinemet)
-most effective drug of Parkinson's disease -when ingested the drug is converted into dopamine in the CNS Carbidopa is used in conjunction with Levodopa as carbidopa is an inhibitor that allows levodopa to get past the periphery and through blood brain barrier.
28
Levodopa/Carbidopa (Sinemet) dosage forms and adverse effects
Regular release or Controlled release Adverse effects: nausea, vomiting, postural hypotension, syncope (passing out), dizziness, tachycardia, dyskinesias, hallucinations, confusion
29
Levodopa/Carbidopa (Sinemet) key points
- Wearing off or end of dose effects before next dose given - ON/OFF phenomenon. fluctuations from mobile to immobile states. they want to move but their body simply doesn't - DYSKINESIAS - occurs in 50% of Pt's after 5yrs of treatment. restless-type movements of head, face, trunk and respiratory muscles
30
COMT inhibitors
Catechol O-methyltransferase (COMT) inhibitors allow a larger amount of Levodopa to reach the brain. COMT helps provide a stable, constant supply of levodopa so it last longer Used in conjunction with levodopa when 'wearing-off' and 'on/off' periods take place. Allows patients relief from their symptoms without increasing their levodopa dosage
31
Selegiline
Used in early stages of Parkinson's disease it is a selective inhibitor of the enzyme monoamine oxidase – B (MOA-B) which breakdown dopamine. The dose must be given in the morning and noon because an adverse effect is insomnia and nausea
32
Dopamine agonists (stimulate receptors)
Stimulates dopamine receptors and may be effective in early Parkinson's disease. Usually used in combination with levodopa. Medications include: Bromocriptine Pergolide Pramipexole & Ropinorole (may cause sleep attacks) **Blood pressure frequently during initiation of therapy A/E - nausea, vomiting, postural hypotension, constipation
33
Anti-cholinergic agents medications and uses
Medications: trihexyphenidyl (Artane), benztropine (Cogentin), diphenhydramine (Benadryl), procyclidine (Kemadrine) - Block the effects of acetylcholine by binding to the ACH receptors Beneficial in patients with tremor and dystonia's
34
Anticholinergic agents adverse affects (Alice in wonderland)
``` Cognitive impairment, dry mouth, blurred vision, constipation and urinary retention, decreased perspiration (hot and red skin) Mad as a hatter Hot as a hare blind as a bat dry as a bone red as a beet ```
35
Amantadine uses in PD
Used for short-term treatment in mild disease. | A/E - vivid dreams, sedation, dry mouth, rose coloured mottling (blotchiness)
36
Surgery in a person with advanced Parkinson's disease
Pallidotomy | It is a procedure where a tiny electrical probe is placed in the globus pallidus to destroy a small area of brain cells
37
What is Alzheimer's disease and signs of it
A neurodegenerative disease that is found in people usually over age 65 Signs/symptoms: cognitive deterioration, declining activities of daily living, neuropsychiatric symptoms or behavioral changes
38
Stages to Alzheimer's disease (progression)
1. mild-connitive impairment: (7yrs) short term memory loss 2. mild Alzheimer's: (2yrs) reading problems, poor object recognition 3. Moderarte Alzheimer's: (2yrs) poor judgement, short attention, impulsivity. 4. Severe Alzheimer's: (3yrs) visual problems
39
Mechanism of action about Alzheimer's disease
Neurofibrillary tangles, Neuritic plaques, and decreased ACh are found on autopsy. GOAL: preserve Pt functioning and delay onset of disease as there is no cure
40
Alzheimer's disease medications
Cholinesterase inhibitors (ChEI): Donepezil (aricept), Rivastigmine (Exelon), Galantamine (reminyl). N-Methyl-d-aspartate (NMDA) antagonists: Memantine (Ebixa)
41
AD - Cholinesterase inhibitors (ChEI) mechanism of action and effect
Used for mild to moderate AD to improve or maintain cognitive function for 6 to 18 months, which can delay the Pt from entering a nursing home. A/E - nausea, vomiting, insomnia. others include rhinitis, sialorrhea (drooling), urinary incontinence, bradycardia
42
AD - NMDA receptor antagonist (memantine)
By binding to the NMDA receptor, memantine is able to inhibit neuronal excitotoxicity associated with glutamate. treated for moderate to severe cases of AD A/E: dizziness, headache, somnolence (sleepiness), and restlessness.
43
Analgesics Description of nerve pain versus muscle pain
``` Nerve = burning, stabbing, electric shock-like (pins/needles) Muscle = tenderness, achiness, stiffness ```
44
Three types of Analgesics
1. Acetaminophen 2. Anti-Inflammatory Agents (Non-steroidal anti-inflammatory drugs / NSAIDs, Cyclooxygenase-2 inhibitors / COX-2) 3. Narcotics
45
Acetaminophen uses and doses
``` Inhibits brain prostaglandins. Antipyretic = decreases fever analgesic = decreases pain **Not an anti-inflammatory DOSE: 650-1000mg q6h Max=4000mg per 24h overdose can lead to damage to liver ```
46
Acetaminphen A/E and overdose
very few a/e at therapeutic doses (not really any side effects) overdose: Acute >7.5g in single ingestion. chronic >4.5g daily over months to years Overdose situation will administer N-Acetylcysteine (NAC or Mucomyst) as antidote (it smells like rotten eggs)
47
anti-inflammatory drugs (NSAIDS and COX-2)
``` NSAIDS: Acetylsalicylic acid (ASA, Aspirin) Ibuprofen (Advil) Naproxen (Aleve, Naprosyn) Diclofenac (voltaren) Indomethocin (Indocid) Ketorolac (Toradol) ``` COX-2 inhibitor: Celecoxib (Celebrex) longer term Pt. takes daily
48
pharmacology of NSAIDs and COX-2 on prostaglandins
NSAIDs: effects prostaglandins associated with pain, fever, and inflammation. A/E to NSAIDs: GI mucous integrity, platelet and renal function COX-2: effects prostaglandins associated with pain, fever, and inflammation w/o the adverse effects
49
NSAIDs function and effects
Inhibit cyclooxygenase (COX 1 & 2) enzymes ASA is cardioprotection. usual dose = 325-1000mg q4-6h prn A/E: Tinnitis (ringing in ear) suppresses platelet aggregation (bleeding) renal dysfunction gastrointestinal damage (ulcer) NOTE: KETOROLAC (Toradol) only NSAID available in IV route. Also, try to give w/food or milk to decrease stomach upset
50
COX-2 inhibitors
inhibit cyclooxygenase (COX 2 only) enzyme to decrease local inflammation analgesic and anti-inflammatory effects Note: there have been conflicting studies regarding the benefits compared to NSAIDs but they may have less risk of bleeding and stomach ulcerations