Week 12 Drugs that affect the CNS & ANS Flashcards
Topiramate (Topamax) is being prescribed to a school-aged child for partial seizures. As the summer approaches and temperatures rise, the nurse practitioner needs to include which of these in patient education?
Stay hydrated and avoid extreme high temperatures due to risk of decreased sweating and high fever.
Topiramate can cause oligohidrosis and hyperthermia.
A 23-year-old patient who suffered from tonic-clonic seizures was recently discharged from an acute care hospital. The patient needs continued education regarding the daily administration of phenytoin (Dilantin). Which statement by the APN demonstrates the important education needed when phenytoin (Dilantin) is administered?
Recommended teaching is to avoid alcohol
Phenytoin (Dilantin)
Drug Class Indication MOA #3 ADR #6 (Neuro, Cardiac, GU) Caution #3 Contraindication preg/lact peds clinical #2
Hydantoin
Indication: Tonic-clonic & partial complex seizures
MOA:
- Stabilize/Inhibit electrical discharges by affecting influx of Na+ ions
- Highly protein bound
- CYP450/liver metabolism
ADR:
- Neuro: agitation, ataxia
- Cardiac: Hypotension/Tachycardia
- GU (urine retention/discolor)
- SI
- Blood dyscrasias
Caution:
- Elderly (d/t highly protein-bound & sensitive to renal/hepatic impairment)
- hypotension
- HF
Contraindications:
-Sinus bradycardia, 2nd 3rd AV block,
Pregnancy/Lact: NO!
Pediatrics: OK
Clinical Considerations:
- Narrow Therapeutic range
- Sudden withdrawal = rebound seizures
Carbamazepine (Tegretol)
Indication MOA ADR #6 Caution Black Box Warning #4 preg/lact Monitoring #2 Patient education
Carbamazepine
Indication:
-Focal & Generalized onset seizures; Bipolar disorder
MOA:
-CYP450 inducer
ADR:
- Drowsy
- Tremor
- Behavior change
- SI
- multiorgan reaction
- Hepatoxicity
Caution:
-Elderly (increased confusion)
BLACK BOX WARNING:
- Development of Steven-Johnson syndrome
- Toxic epidermal necrolysis in Chinese (Skin peeling/blister)
- Blood Dyscrasia (depress bone marrow)
- Dermatologic toxicity
PREG/LACT: NO
Monitoring:
- CBC, CMP, TSH
- Narrow therapeutic Range
impairs thyroid function
Patient Education:
- Report new-onset skin lesions, bruising, fever, or sore throat
- Do not take with grapefruit juice
Lamotrigine (Lamictal)
Indication MOA ADR #5 Black box Clinical consideration Patient Education Drug Interaction Preg/lac peds @ increase risk for?
Adjunctive Tx w/ valproate & phenytoin*
Indication:
Partial seizures
Primary generalized tonic-clinic seizures
MOA:
-Inhibit presynaptic release of glutamate & aspartate
ADR:
- GI (N/V, constipation)
- Cardiac (CP, peripheral edema)
- CNS: (Sedation, diplopia, ataxia)
- SI (rare)
- Blood dyscrasia (rare)
- Multiorgan sensitivity reaction (rare)
BLACK BOX WARNING:
-Serious skin reactions (SJS)
Clinical Considerations:
- rebound status epilepticus w/sudden withdrawal
- Levels decreased by estrogens
Patient Education:
- Report New onset rash
- Avoid alcohol & OTC drugs
- hydration
Drug Interaction:
-Oral contraceptives (decrease levels of lamo)
PREGNANCY/LACTATION: NO
PEDS: >2years (increased risk of skin reaction)
Zonisamide
Indication MOA ADR #3 Contraindication Clinical Consideration Preg/lact Peds
Indication:
Partial seizures in adults
MOA:
-Blocks voltage dependent Na+ & Cl- channels
ADR:
- Somnolence
- blood dyscrasia (rare)
- Decreases sweating ==risk hyperthermia ***
Contraindication:
-Sulfa allergy
Clinical Consideration:
Rebound Seizures with sudden withdrawal
PREG/LACT: NO
Peds >16 years
ethosuzimide (Zarontin); phensuximide (Celontin)
drug class Indication MOA ADR #5 (3 rare) Patient Education #2 Clinical Consideration #2 Drug Interaction Preg lact peds
Succinimides
Indication:
-Absence seizures**
MOA:
- Delays Ca++ influx into neurons
- Decrease nerve impulses & transmission in motor cortex
ADR:
- GI (most common)
- CNS: Sedation
- Mood changes
- SI (rare)
- Blood dyscrasia (rare)
- systemic lupus erythematosus symptoms (rare)
Patient Education:
- Take w/food (GI upset)
- Do not take with alcohol
Clinical Consideration:
Narrow therapeutic index
Rebound seizures w/withdrawal
Drug interaction:
Birth control effectiveness decreased (back up needed)
Pregnancy: OK
Lactation: NO
Peds: >3years
Valproic Acid
Indication MOA #3 ADR #6 Caution Black Box Warning #2 Clinical Consideration #2 preg/lact Peds
Indication: Focal, gen., focal onset impaired awareness, absence seizures
MOA:
- ^GABA bioavailability
- mimic GABA action at postsynaptic sites
- Blocks Voltage Na+ channels
ADR:
- H/A
- Drowsy
- Weight gain
- Behavior changes
- SI (rare)
- Brain Atrophy (rare)
Caution:
-Elderly (Somnolence/Beers list)
Black Box Warning:
- Hepatoxicity
- Severe Pancreatitis
Clinical Consideration:
- Narrow therapeutic index
- Rebound seizures w/withdrawal
Pregnancy/Lact: NO
Peds >2years
Gabapentin
Indication MOA ADR #4 Caution #3 Peds Clinical Consideration #2
Indication: Focal Seizure
MOA:
-GABA analogue that binds
ADR:
- Drowsy/fatigue
- Peripheral Edema
- Neuropsych events
- SI (rare)
Caution:
- Renal impairment (excreted in urine)
- Elderly (lethargy Beers list)
- Substance abuse history
Peds >3 years (high-risk Neuro events)
Clinical Consideration:
- Absorption increased if taken with food
- Rebound seizures
Topiramate (Topamax)
Indication MOA #2 ADR #4 Caution Preg peds Clinical Consideration
Indication: Focal Seizure, tonic clonic seizure, migraines
MOA:
- Block Na+ channel
- potentiate GABA
- Not extensively metabolized, only minor phase one metabolism and high amount of unchanged drug in urine**????
ADR:
- Lethargy
- Mood changes (lethargy, depression)
- SI (rare)
- Decreased sweating/hyperthermia (rare)
Caution:
-Elderly (lethargy)
Preg: NO
Peds >3months
Clinical Considerations:
-Rebound seizures
Levetiracetam (Keppra)
Indication MOA ADR #5 Fun fact Caution preg peds Clinical Consideration
Indication: Focal and gen. onset seizure
MOA:
-Inhibit burst firing w/o affecting normal neuronal excitability
ADR:
- Somnolence*
- Mood change/Nervousness
- SI (rare)
- Derm reaction (rare)
- Blood dyscrasias (rare)
***Fewer drug-drug interactions
Caution:
-Elderly (somnolence)
Pregnancy: OK
Peds >1month
Clinical Consideration:
-Rebound seizures w/ withdrawal
What does the toxicity of Valproic Acid look like?
CNS depression, Confusion, Jaundice
**BBW hepatoxicity
What does the toxicity of Succinimides look like?
CNS depression, respiratory depression, N/V
**High risk sedation
Toxic symptoms of Carbamazepine (Tegretol)?
Hypertension, Tachycardia, Stupor, Agitation, Respiratory depression, nystagmus, urinary retention, seizures, coma
Anticholinergic Effects
Which anticonvulsant is least sedating?
Phenytoin
A 45-year-old patient is suffering from back pain due to severe muscle spasms. A centrally-acting muscle relaxant, tizanidine (Zanaflex), is prescribed. By which mechanism of action does tizanidine act?
Tizanidine (Zanaflex) binds to central alpha2 adrenergic receptors, which increases the presynaptic motor neuron inhibition and reducing spasticity.
Baclofen
Indication MOA ADR #3 Caution #3 pregnancy
Indication: Muscle Relaxant
MOA: Inhibits transmission mono&polysynaptic reflexes at spinal cord
ADR:
- Drowsy/Confusion/Sedation
- seizures
- Hypotension
Caution:
- Renal
- Elderly (Beer’s list sedating)
- seizure disorder
Pregnancy: NO
Cyclobenzaprine (Flexeril)
Indication MOA #2 ADR #3 Contraindication #4 Caution #2 Peds Clinical Considerations #2
Indication: Muscle Relaxant
MOA:
- mono&polysynaptic spinal cord reflexes;
- inhibits reflex arc to block messages that are maintaining spasm
ADR:
- *Anticholinergic effects
- hallucinations
- sedation
Contraindication:
- Hyperthyroidism
- HF
- Heart block/conduction disturbance
- Acute MI
Caution:
- Glaucoma
- Urinary retention
Peds >12years
Clinical Consideration:
- Risk of Serotonin syndrome
- Should not be used longer than 3 weeks
Tizanidine
Indication MOA ADR #4 Drug Interaction Clinical Considerations #2
Indication: Muscle Relaxant
MOA:
-Alpha2-adrenergic agonists inhibits presynaptic motor neurons
ADR:
- *anticholinergic effects
- Bradycardia
- Hepatoxicity (rare)
- Angioedema (rare)
Drug Interactions:
-CYP450
Clinical Considerations:
- Less sedating than Baclofen and Flexeril
- Do not stop abruptly = rebound tachycardia
What are the signs of serotonin syndrome?
Overactive reflexes & muscle spasms, high temperature, sweat, shivering, mental changes
What is the goal for choinersterase inhibitors to treat Alzheimer’s?
Goal is to prevent degradation of acetylcholine by acetylcholinesterase because it results in enhanced activity of acetylcholine.
Donepezil (Aricept); Rivastigmine (Exelon)
MOA
ADR #3
Drug Interaction #2
Caution #2
Donepezil (Aricept); Rivastigmine (Exelon) MOA: -Indirect cholinergic agonist -inhibits acetylcholinesterase to prevent break down of acetylcholine ADR: -Dizzy -Agitation -Tremor Donepezil drug interaction: -CYP450 -Anticholinergic drugs Caution: -Seizures -QT prolongation
Memantine (Namenda)
MOA
ADR
Caution
Clinical Considerations #2
MOA:
- NMDA Receptor Antagonist
- *Persistent stimulation of NMDA receptors by glutamate contributes to AD**
ADR:
-Confusion/dizzy/somnolence
Caution:
- Cardiovascular disease
- Renal
Clinical Consideration:
- Used in combination with Donepezil or Rivastigmine
- Best for neuropsych symptoms (agitation/behavior disturbances)
What are the signs of Donepezil & Rivastigmine toxicity?
Constricted pupils, excessive salivation, diarrhea
Which adverse drug reaction to a selective alpha1 antagonist would be the best reason to change to a different class of medication?
IMPOTENCE
The leading cause of nonadherence to a treatment regimen with alpha1-adrenergic antagonists is inhibition of ejaculation and impotence. These reactions should be reported to the health-care provider, who may choose a different drug to treat the disorder or change the dosage.
Each selective alpha1 antagonist carries a risk for significant first-dose orthostatic hypotension that may result in syncope, and tends to occur within 30 to 90 minutes of drug administration. How can this adverse reaction be minimized?
Giving the first dose at bedtime
Which alpha-1 selective antagonist would be best for an elderly person with BPH?
Tamsulosin
Which alpha-1 selective antagonist does not cause orthostatic hypotension?
Tamsulosin
Clonidine (Catapres)
Drug Class Indication MOA #2 ADR #5 Caution #3 Contraindication #2 Patient Education
Drug Class: Alpha-2 Agonist (Central)
Indication: HTN, ADHD
MOA:
HTN: stimulate Alpha2 in brainstem to activate inhibition = Reduced Sympathetic response from CNS “downregulates
ADHD: regulates prefrontal activity
ADR:
- Drowsy/Dry mouth
- Bradycardia
- Nightmares
- Impotence
- Constipation
Caution:
- Elderly (bradycardia/orthostatic hypotension)
- Coronary Insufficiency
- CVD
Contraindication:
- History Bradycardia
- Beta blockers (bradycardia)
Patient Education:
-Do not stop abruptly dd/t downregulation»_space;> rapid increase in BP
Methyldopa
Drug Class Indication MOA ADR #6 Caution #2 Contraindication #2 Clinical Consideration #2 Preg/lact Peds
Drug Class: Alpha-2 Agonist
Indication: HTN
MOA: Stimulate central alpha-2 receptors via metabolite alpha-methylnorepinephrine
ADR:
- Edema
- Sedation
- Bradycardia/Hypotension
- elevated LFTs
- blood dyscrasias (rare)
- Hepatoxicity (rare)
Caution:
- Severe coronary insufficiency
- Cerebrovascular disease
Contraindication:
- history bradycardia
- Active renal/liver disease
Clinical Consideration:
- Tolerance may need to add diuretic
- Avoid with Beta blockers (bradycardia)
Pregnancy/Lact: no
Peds: NO
Beta blockers (BBs) are generally contraindicated in which patient?
unstable bronchospastic disorders such as asthma.
Beta blockers play a key role in the reduction of catecholamine response that stimulates the sympathetic nervous system (SNS). How do these medications perform their action?
Beta blockers occupy the receptor, impeding the ability for the neurotransmitter to stimulate the SNS.
Metoprolol; Atenolol
Drug Class Indication #4 MOA ADR #5 Caution #3 Contraindication #3 Peds Clinical Consideration #2
Drug Class: Selective Beta blocker
Indication: HF HTN Afib Angina, post MI
MOA:
-Block beta-1
ADR:
- Hypertension
- Bradycardia
- Dizzy, fatigue*
- depression
- Impotence/decreased libido
Caution:
- PVD
- DM (Masks symptoms of hypoglycemia except for sweating)
- Hyperlipidemia (decreases HDL, Increases cholesterol)
Contraindication:
- History bronchospasm
- Heart Block
- Pregnancy 1st trimester
Peds: NO
Clinical Consideration:
- Do not abruptly stop = rebound hypertension, tachycardia, MI
- Taper over 1-2 weeks
Propranolol
Drug Class Indication #4 MOA Caution #3 Contraindication #2 Clinical Consideration
Drug Class: nonselective beta blocker
Indication:
- afib/HTN/stable angina
- essential tremor
- Migraine prophylaxis
- Thyroid storm
MOA:
-Blocks beta1 & beta2
Caution:
- DM
- PVD
- hyperlipidemia
Contraindication:
- heart block
- Asthmatics
Clinical Consideration:
-Do not abruptly stop
Which selective beta blocker has the longest half life?
Atenolol; Qdaily dosing
Which betablocker can be used to treat preeclampsia?
Labetalol
Most antiepileptic drugs, such as perampanel, carry an increased risk of suicidal behavior or ideation. In addition to this adverse effect, which other psychosocial precaution is included for perampanel?
boxed warning for changes in mood, including hostility, aggression, and homicidal ideation.
Which phenobarbital result suggests that it is in the therapeutic range?
The therapeutic range for phenobarbital is 12 to 40 mcg/mL.
Cholinergic blockers are useful adjuncts early in the course of Parkinson’s disease to control tremor by relaxing smooth muscle and to control oral secretion, where drooling can be an issue. Which of these could potentially worsen Parkinson’s symptoms if given concurrently with levodopa?
Trihexyphenidyl
levodecreases the total bioavailability of levodopa, requiring an adjustment in dosage or risk potential worsening of Parkinson’s disease.
Which medication would both reduce the pain relief of a pure opioid and initiate an abstinence syndrome if given to a narcotic-addicted patient?
Pentazocine (Talwin)
A mixed agonist-antagonist will block the mu receptor, prompting an abstinence syndrome. Its antagonism will also reduce the pain relief of a pure opioid.
