Neurology Flashcards
Parkinson Disease (PD):
-Define
-Pathophysiology
PD: degenerative neurological disorder when neurons die in basal ganglia inlcuding substantia nigra, striatum, and thalamus
Pathophysiology: cells that die produce DA which enables smooth, coordinated muscle function and movement –> less instructions to brain –> movement problems
-Potential contributors: mutation in LRRK2 gene, alpha-synuclein (major constituent of Lewy bodies)
Parkinson Disease (PD):
-TRAP Major Symptoms
-Other symptoms
-What is AIMS?
TRAP:
-T: Tremor when resting
-R: Rigidity: in legs, arms, trunk, and face (mask-like face)
-A: Akineasia/bradykinesia: lack of / slow start in movement
-P: Postural instability: imbalance, falls
Other Symptoms:
-Micrographia: small, cramped handwriting
-Shuffling walk, stooped posture
-Muffled speech, drooling, dysphagia
-Depression, anxiety (psychosis in advanced disease)
-Constipation, incontinence
AIMs: Abnormal Involuntary Movement Scale
Dopamine blocking drugs that worsen PD
- Phenothiazines (ex. prochlorperazine) used for psychosis, nausea, or agitation
- Butyrophenones (ex. haloperidol, droperidol)
- First and second generation antipsychotics (lowest risk w/ quetiapine)
- Metoclopramide: renally-cleared drug that accumulates in older adults
Parkinson Diasease (PD):
-General TX
-TX of symptoms: tremor, dyskinesias, severe “freezing” episodes, orthostatic hypotension
-TX of other psychiatric-related conditions (depression, psychosis)
Primarily: replace dopamine
-Dopamine agonists: levodopa (prodrug of DA) –> MOST EFFECTIVE
-Drugs that increase dopamine: catechol-o-methyltransferase (COMT) inhibitors, MAO-B
-Decrease ACh (since DA depletion triggers ACh excess): centrally-acting anticholinergics (benztropine) for tremor
Symptom TX:
-Tremor: amantadine or selective MAOI-B: can be helpful initially for tremor –> non-selecitive MAOI-B CI since block drug metabolism of for replacing dopamine
-Dyskinesias: amantadine
-Severe “freezing” episodes in advanced disease: apomorphine
-Orthostatic hypotension: droxidopa
Other Psychiatric related conditions:
-Depression: SSRIs and SNRIs (concerns of contributing to tremor), secondary amine TCAs, pramipexol (DA agonist)
-Psychosis: quetiapine, pimavanserin
Carbidopa/Levodopa:
-Brand
-MOA
-ROA
-Dosing/Dosing frequency
-Storage for Duopa cassettes
Brand: Sinemet
MOA:
-Levodopa: precursor of DA
-Carbidopa: inhibits dopa decarboxylase enzyme, preventing peripheral metabolism of levodopa
ROA: PO, inhaled (Inbrija), J-tube (Duopa)
Dosing:
-Titrate cautiously starting at 25/100mg PO TID for IR tablets or 50/200mg PO BID (ER tablets) –> do NOT D/C abruptly
-ER tablet CAN be cut in half
-70-100mg/day of cardidopa required to inhibit dopa decarboxylate
-Rytarvy: can take whole or sprinkle on applesauce
Duopa cassettes: freezer, thaw prior to dispensing (good for 12 weeks upon refrigeration)
Carbidopa/Levodopa:
-AVEs
-Long term usage concern
-CI
-DDIs
AVEs: nausea, dizziness, orthostasis, dyskinesias, hallucinations, psychosis, xerostomia, dystonias, confusion
-Can cause brown, black, or dark discoloring of urine, salive, or sweat and can discolor clothing
-Positive Coomb’s test: D/C drug (hemolysis risk)
-Unusual sexual urges, priapism, increased uric acid
-Rytary: SI and attempts
-Duopa: GI complications
Long term: can lead to fluctuations in response and dyskinesias
CI: non-selective MAOIs (phenelzine, isocarboxazid) within 14 days, narrow angle glaucoma
DDIs:
-do NOT use w/ dopamine blockers
-Non-selective MAOIs: 2 week seperation needed
-Iron and protein-rich foods can decrease absorption
Catechol-O-Methyltransferase (COMT) Inhibitors:
-Drugs/Brands
-MOA
-Dosing
-AVEs
Drugs: entacapone (Comtan, with Sinemet: Stalevo), opicapone (Ongentys), talcapone (Tasmar)
MOA: prevents COMT from breaking peripheral version down of levodopa to increase duration of action of levodopa
-CANNOT be used monotherapy since it ONLY prolongs duration
Dosing: 200mg PO with each carbidopa/levodopa dose
-May need to decrease levodopa dose by 10-30% when adding
AVEs: similar to levodopa, due to increase increasing its duration
-Dyskinesias can occur earlier with COMT inhibitors
-Tolcapone: rarely used due to hepatoxocity
Dopamine agonists:
-Drugs/Brands
-ROA
-Administration considerations
-TX
Drugs: pramipexole (Mirapex), ropinirole (Requip XL), rotigotine (Neupro)
-Bromocriptine: used be in drug class, but NO longer recommended
ROA: PO, patch (Neupro)
Administration:
-Do NOT D/C abrupty (withdrawl symptoms)
-Patch: QD to stomach, thigh, hip, side of body, shoulder, or upper arm (do NOT use same site for at least 14 days), remove patch before MRI; avoid if allergy/sensitivity to sulfites
TX: PD, RLS
Dopamine agonists:
-AVEs
-Warnings
-DDIs
AVEs: dizziness, N/V, dry mouth, peripheral edema, constipation
-Rotigotine: hyperhidrosis
Warnings:
-Somnolence (including sudden daytime sleep attacks), orthostasis, hallucinations, dyskinesias, impulse control disorders
-Rotigotine patch: application skin rxns
-Pramipexole: postural deformity (ex. bent spine, dropped head), rhabdomyolysis
DDIs: ropinirole is a CYP1A2 substrate (caution w/ inhibitors)
Apomorphine:
-Brand
-MOA
-ROA
-Administration considerations
-TX
Brand: Apokyn
MOA: dopamine agonist
ROA: SQ
Administration:
-MUST do test dose in medical office due to BP drop
-For emesis prevention, give trimethobenzamide (Tigan) or similar drug starting 3 days before intial dose
TX: rescue movement in PD
Apomorphine:
-AVEs
-CI
-Monitoring
AVEs: severe N/V, hypotension, yawning, dyskiniesias, somnolence, dizziness, QT prolongation
CI: do NOT use w/ 5-HT3 antagonists (ex. ondansetron) due to severe hypotension and loss of consciousness
Monitor: suprine and standing BP
evere N/V, hypotension
Amantadine:
-Brand
-MOA
-ROA
-TX
-AVEs
-Warnings
-CI
Brand: Gocovri:
MOA: blocks DA reuptake in presynaptic neurons and increases DDA release from fibers
ROA: PO
TX: dyskinesias associated w/ peak dose of carbidopa/levodopa
AVEs: dizziness, orthostatic hypotension, syncope, insomnia, abnormal dreams, dry mouth, constipation
-Cutaneous rxn called livedo reticularis (reddish skin mottling which requires D/C)
Warnings: somnolence (including falling asleep w/o warning during activities of daily living), compulsive behaviors, psychosis (hallucinations, delusions, paranoia)
CI: live vaccines
Selective MAO-B inhibitors for PD:
-Drugs/Brands
-MOA
-ROA
-Administration considerations
Drugs: selegiline (Zelepar, Emsam), rasagiline (Azilect), safinamide (Xadago)
MOA: block breakdown of DA
ROA: PO
Administration:
-May need to reduce levodopa dose when adding
-Selegiline: can be activating, do NOT dose at bedtime
Selective MAO-B inhibitors for PD:
-Warnings
-CI
-Monitoring
-DDIs
Warnings: serotonin syndrome, hypertension, nausea, CNS depression, dyskinesias, impulse control disorders, caution in psychotic disorders (may exacerbate) or opthalamic disorders (Xadago)
-Rasagiline: HA, joint pain, indigestion
CI:
-Use with MAOIs, SNRIs, TCAs, opioids, linezolid, etc.
-Xadago: severe hepatic impairment
Monitoring: BP, serotonin syndrome, visual changes (Xadago)
DDIs:
-Any agent to increase risk of serotonin syndrome
-Do NOT use w/ DA, tyrosine, phenylalanine, tryptophan, or caffeine
-Avoid foods high in tyramine (anything pickled, smoked, aged/matured, air-dried or cured meat)
-Rasagiline: CYP1A2 sbustrate (limit dose to 0.05mg QD w/ Cipro or other inhibitors)
Centrally-acting anticholinergics for PD:
-Drugs/Brands
-AVEs
-Warnings
Drugs: benztropine (Cogentin), trihexyphenidyl
AVEs: peripheral and central anticholinergic effects (dry mouth, constipation, urinary retention, blurry vision, mydriasis, somnolence, confusion, tachycardia)
Warnings: avoid use in elderly
Istradefylline:
-Brand
-MOA
-ROA
-TX
-AVEs
-Warnings
Brand: Nourianz
MOA: adenosine receptor antagonist
ROA: PO
TX: combed w/ levodopa/carbidopa to reduce “off” episodes
AVes: nausea, constipation
Warnings: hallucinations, dyskinesias, impulse control disorders
Droxidopa:
-Brand
-MOA
-ROA
-TX
-AVEs
-BBW
Brand: Northera
MOA: alpha/beta agonist
ROA: PO
TX: neurogenic orthostatic hypotension
AVEs: syncope, falls, HA
BBW: supine HTN
-Monitor supine BP prior to and during TX
-Elevate bed of head and measure BP in this position
-If supine HTN NOT managed, reduce dose or D/C
Define mild cognitive impairment (MCI) versus dementia
-S/Sx of dementia
MCI: age-associated cognitive decline
Dementia: more severe decline in cognitive progression with intellectual and social abilities progressively worsening and functioning imapired
S/Sx of dementia: memory loss, difficulty planning/organizing, getting lost in familiar places, repeating words/information, difficulty finding words for common objects, inability to learn/remember new info, apathy and social disengagement, delusions and agitation, poor coordination and motor function
Pathophysiology of Alzheimer’s disease
-Diagnosis
Alzheimer’s disease: neuropathologic changes (amyloid beta plaques, tau tangles) that lead to death of cholinergic neurons, resulting in decreased ACh
Diagnosis:
Rule out reversable causes: vitamin D or B12 deficiency, depression, infection, medications
-Mini-Mental State Exam (MMSE): max score of 30; <24 indicates memory disorder
-Montreal Cognitive Assessment (MoCA)
-Brain imaging
-CSF and blood tests to measure amyloid beta and tau concentraions
Alzheimer’s Disease:
-Non-pharm TX
-Natural products
Non-pharm:
-Control BP, BG, and cholesterol to prevent vascular dementia
-Physical activity, healthy diet, and cognitive rehabilitation may prevent dementia or improve symptoms
Natural Products:
-Vitamin E (2000 IU) daily: may slow rate of decline in pts w/ mild-moderate dementia
-Tohers: acteyl-L-carnitine, ginkgo biloba, vinpocetine
Alzheimer’s Disease:
-General pharm TX
-Co-existing psychiatric condition TX
Pharmacological TX: modest benefits that may SLOW clinical decline
-Mild/moderate dementia: acetylcholinesterase inhibitor (donepezil, rivastigmine, galantamine)
-Moderate/severe dementia: acetylcholinesterase inhibitor +/- memantine (combo more likely to delay progression)
-Amyloid-beta-directed antibodies (aducanumab, lecanemab): reduce amyloid beta plaques, but clinical benefit yet to be demonstrated
Co-existing psychiatric TX:
-Depression, anxiety: can use antidepressants
-Agitation, psychosis: address underlying casues and use non-pharm –> then trial of antipsychotic therapy if significant distress or harm to themself/others (should be D/C when possible due to increased risk of death BBW)
Drugs that worsen dementia
- CNS deperessants: barbiturates, BZDs, opioids, hypnotics, skeletal muscle relaxants
- Drugs with Anticholinergic Effects: antimetics, antihistamines, central anticholinergics, peripheral anticholinergics, TCAs
- Antipsychotics
Acetylcholinesterase Inhibitors:
-Drugs/Brands
-MOA
-ROA
Drugs: donepezil (Aricept, Adlarity, + memantine = Namzaric), rivastigmine (Exelon), galantamine
MOA: inhibits centrally active acetylcholinesterase enzyme that breaksdown ACh to increase ACh
ROA:
-Aricept: ODT, tablet
-Adlarity: patch
-Rivastigmine: capsule, patch
Acetylcholinesterase Inhibitors:
-AVEs
-Warnings
-DDIs
AVEs: insomnia, dizziness
Warnings:
-Cardiac effects, including bradycardia, AV block, syncope
-GI effects including N/V/D, weight loss, and/or anorexia (risk w/ higher doses and in low body weight <55kg)
-Skin rxns (all formulations), including allergic contact dermatitis (rivastigmine) and SJS (galantamine)
-Donepezil: QT prolongation
DDIs:
-Caution with drugs that lower HR
-Drugs that have anticholinergic effects can reduce efficacy of this drug class
-Due to increased gastric acid secretion, caution with drugs that have GI bleed risk (ex. hx of GI ulcers, NSAIDs)
Acetylcholinesterase Inhibitors Administrations:
1. Donepezil should be dosed QHS or QAM?
- Slower titration (Q4-6 weeks) may decrease _______ side effects. If treatment interrupted for ___ or more days, retitrate from starting dose.
- Adlarity is a patch that is dosed Q______ and should be stored in _______. Rotate application sites and do NOT use same site within ____ days. Where to apply patch?
- QHS due to nausea (but QAM if experiencing insomnia)
- GI; 3 days
- week; refrigerator (take patch out prior to get to room temp and apply within 24 hours of taking out of fridge); 14; upper or lower back (preferred) or upper buttocks or upper outer thigh
Acetylcholinesterase Inhibitors Administrations:
1. ________ patch should be removed before MRI. This patch should be applied Q_____ to __ or ____ or ___. Rotate application sites and do NOT use same site within _____days.
- True or False: galantamine solution can be mixed with liquid and taken immediately.
- True or false: PO rivastigmine and galantimine should be taken CF.
- If stable on donepezil ___mg, can switch to _______ and titrate weekly.
4.* Exelon (rivastigmine); QD; upper or lower back (preferred) or upper arm or chest; 14
-Apply to back to avoid pt trying to remove*
- True
3 True
4 10mg; Namzaric (memantine 7mg/donepezil 10mg QHS)
Memantine:
-Brand
-MOA
-ROA
-Administration considerations
-AVEs
-Warnings
Brand: Namenda (with donepezil: Namzaric)
-NaMenDA = NMDA
MOA: N-methyl-D-aspartate (NMDA) receptor inhibitor which prevents gluatamate, an excitatory neutrotransmitter from binding to cause overstimulation and neuronal death
ROA: PO
Administration:
-ER capsule, Namzaric: do NOT crush or chew; capsules can be sprinkled on applesaurce and swallowed immediately
-Oral solution: use provided dosing syringe
AVEs: generally well tolerated
-Dizziness, confusion, HA, constipation
Warnings: caution w/ drugs or conditions that increase urine pH, reducing clearance of memantine (sodium bicarbonate, acetazolamide, severe UTI)
Seizures:
-Temporary conditions that can induce seizures
-Medications that lower seizure threshold/induce seizures
Temporary conditions: fever (common in children), infection, alcohol withdrawl, hypoglycemia, electrolyte abnormalities
Drugs that lower seizure threshold:
-Analgesics: opioids (especially tramadol, meperidine)*
-Anti-infectives: quinolones, carbapanems, cephalosporins, PCNs, meflorquine
-Psychiatric medications: bupropion, antipsychotics (especially clozapine), lithium, TCAs*
*=high dose and/or renal impairment increases risk
Focal versus generalized seizures
Motor versus non-motor seizure symptoms
Focal seizures: starts on one side of brain, but can spread to other side; further classified as either focal aware (no loss of conscioussness) or focal seizure w/ impaired awareness
Generalized seizures: start on both sides of the brain; pt losses consciousness or is unaware during seizure
Motor symptoms: sustained rhythmical jerking movements (clonic), limp or weak muscles (atonic), muscle twitching (myoclonus), and rigid or tense muscles (tonic)
Non-motor symptoms: changes in sensation, emotions, thinking, or cognition
Define: tonic-clonic seizures, absence seizures, and status ellipticus
Tonic-clonic seizures: uncrontrolled jerking movements
Absense seizures: generalized seizures with non-motor symptoms
Status ellipticus: seizure that lasts 5 minutes or longer
Status epilepticus: explain what do during the following phases:
1. Stabilization phase (0-5 minutes)
- Initial TX phase (5-20 minutes)
- Second TX phase (20-40 minutes)
- Third TX phase (refractory)
- Stabilization Phase
-Stabilize circulation, airway, and breathing
-Time seizure and start ECG
-Check ASM (antiseizure medication) levels and electrolytes
-If BG low, give dextrose - Initial TX Phase: if seizure continues, give IV lorazepam, IM midazolam, or IV diazepam
-Alternatives: rectal diazepam or intranasal or buccal midazolam - Secondary TX Phase: if seizure continues, give non-BZD anticonvulsant: IV fosphenytoin, valproic acid, or levetiracetam
-Alternative: IV phenobarbital - Refractory TX Phase: no clear evidence to guide therapy; repeat second line or midazolam, phenobarbital, or propofol
Chronic Seizure Management: General TX
- Anticonvulsant - do NOT stop abruptly (could lead to increased seizures)
-Broad spectrum (treat both focal and generalized seizures): lamotrigine, levetiracetam, topiramate, valproic acid
-Narrow spectrum (treat focal seizures): carbamazepine, phenytoin
-Absence seizures: ethosuximide - Adjunctive - medical marijuana (cannibas), ketogenic diet, vagal nerve stimulation, or surgical intervention
Epidiolex (cannabidiol = CBD):* does NOT contain tetrahydrocannabinol (THC)*
-Consider additive CNS effects (somnolence, euphoria, anxiety, paranoia) and DDIs
-Typically for seizures associated w/ Lennox-Gastaut syndrome, Dravet syndrome, or tuberous sclerosis complex
Ketogenic diet: high fats, normal protein, and low carbohydrates (usually 4:1 ratio of fat:combined protein and carbohydrates)
-Forces body to breakdown fatty acids into ketone bodies as energy source which can pass into brain and replace glucose (ketosis)
-Consider vitamin supplementation
-Ex. Eggs, leafy vegetables, pork, poultry, beef, nuts, seeds, olive oil, coconut oil, seafood, cheese
Antiseizure medications (ASMs): explain the purpose of the following drug targets:
-GABA
-Glutamate
-Na channels
-Ca channels
GABA: gamma-aminobutyric acid, inhibitory neutrotransmitter –> goal to enhance
Glutamate: excitatory neutrotransmitter –> goal to reduce
Na channels: reduce to decrease neuronal firing rate
Ca channels: reduce to slow down or stops transmission of electrical signals
What risks do antiseizure medications (ASMs) all usually have?
-CNS depression
-Cognitive impairment, fall risk
-Suicidal risk
-Bone loss as soon as two years after starting (fracture risk)
-Many: rash (including SJS/TENs) or DRESS
Antiseizure medications: what vitamins should be considered to supplement?
-ALL: vitamin D and calcium
-Child of womenbearing age: folate
-Valproic acid: possibly carnitine
-Lamotrigine and valproic acid, if alopecia develops: biotin, selenium, and zinc
Antiseizure medications: what general DDIs should be considered?
-Highly protein bound: clobazam, phenytoin, valproic acid
-Enzyme inducers: carbamazepine, oxcarbazepine, phenytoin, fosphenytoin, phenobarbital, primidone
-Enzyme inhibitor: valproate
Lamotrigine:
-Brand
-MOA
-ROA
-TX
Brand: Lamictal, Lamictal ODT, Lamictal Starter Kit, Lamictal XR
MOA: inhibits Na channels and decreases glutamate
ROA: PO
TX: broad spectrum anticonvulsant (focal and generalized seizures), bipolar disorder
Lamotrigine:
-AVEs
-Warnings
-BBW
-Monitoring
AVEs: alopecia (supplement biotin, zinc, and selenium), N/V, somnolence, rash, tremor, ataxia, impaired coordination, dizziness, diplopia, blurred vision
Warnings: multiorgan hypersensitivity rxns (DRESS), aseptic meningitis, blood dscrasias, cardiac rhythm abnormalities, serious rare immune system rxns (hemophagocytic lymphohistiocytosis = HLH)
BBW: serious skin rxns (SJS, TENs) –> D/C at any sign (reason for titration)
Monitoring: rash, fever
Lamotrigine Dosing:
1. What is the typical starting dose?
- When should the titration be re-started?
- Blue vs. orange vs. green starter kit
- 25mg PO QD for week 1 and 2
- If D/C for 5 or more half lives (>6 days for most patients)
- Starter Kits: select based on DDIs (UGT can alter serum concentrations)
-Blue = lower dose –> take if on valproic acid (B for “below”)
-Orange = normal dose –> take if NO interacting medications
-Green = higher dose –> take if pt taking enzyme inducer (ex. carbamazepine, phenytoin, phenobarbital, primidone) and NOT taking valproic acid (G for “grow higher”)
**Oral estrogen-containing contraceptives may lower lamotrigine as well
Levetiracetam:
-Brand
-MOA
-ROA
-IV to PO ratio
-TX
Brand: Keppra, Keppra XR
MOA: inhibits vesicle fusion via binding to SV2A proteins
ROA: PO, IV
-IV to PO ratio: 1:1
TX: broad-spectrum anticonvuslant (focal and generalized seizures)
-Preferred in pediatrics (easy formulations, pregnancy, and for DDIs
Levetiracetam:
-AVEs
-Warnings
-DDIs
AVEs: somnolence, dizziness, weakness, asthenia
Warnings: psychiatric rxns (psychotic symptoms, somnolence, fatigue, aggression, anxiety, suicidal behavior), anaphylaxis, angioedema, coordination difficulties, severe skin rxns, multiorgan hypersensitivity rxns (DRESS), hematologic abnormalties (anemias mainly), loss of seizure control during pregnancy
DDIs: NO significant DDIs
Topiramate:
-Brand
-MOA
-ROA
-Administration considerations
-TX
Brand: Topamax, Topamax Sprinkle, Trokendi XR, Qudexy XR
MOA: inhibits Na channels
ROA: PO
Administration: Topamax Sprinkle: swallow whole or sprinkle on small amount of soft food (do NOT chew, swallow immediately)
TX: broad-spectrum anticonvulsant (focal and generalized seizures), migraine prophylaxis
Topiramate:
-AVEs
-Warnings
-CI
-DDIs
-Monitoring
AVEs: somnolence, dizziness, psychomotor slowing, difficulty w/ memory/concentratoin/attention, weight loss, anorexia, paresthesia
Warnings: hyperchloremic non-anion gap metabolic acidosis, oligohidrosis (reduced perspiration/hyperthermia mostly in children and from inhibition of carbonic anhydrase), nephrolithiasis, acute myopia and secondary angle-glaucoma, hyperammonemia (alone or w/ valproic acid), visual problems (reversible), fetal harm
CI:
-Trokendi XR: alcohol use 6 hours before or after dose
-Qudexy XR: pt w/ metabolic acidosis taking metformin
DDIs: weak CYP2C19 inhibitor and inducer of CYP3A4
-Phenytoin. carbamazepine, valproic acid, and lamotrigine decrease topiramate levels
-Can decrease efficacy of oral contraceptions (especiall doses >/=200mg/day) –> NON-hormonal contraception recommended
-Can decrease INR in pt on warfarin
Monitoring: electrolytes (especially bicarbonate), renal fxn, hydration status, eye exam (IOP)
Valproate, Divalproex:
-Divalproex vs. Valproate
-Brand
-MOA
-ROA
-TX
-Therapeutic range
Divalproex: valproic acid derivative
Valproate: refers to any formulation of valproic acid, valproate sodium, or divalproex
Brand (divalproex): Depakote, Depakote ER, Depakote Sprinkle
MOA: inhibits Na channels and increases GABA, an inhibitory neutransmitter
ROA: PO, IV
TX: broad-spectrum anticonvulsant (focal and generalized seizures), bipolar disorder, migraine prophylaxis
Therapeutic range: (50-100 mcg/mL (total level)
Valproate:
-AVEs
-Warnings
-CI
-BBW
-Monitoring
AVEs: alopecia (supplement w/ biotin, selenium, zinc), N/V, weight changes (gain > loss), HA, anorexia, abdominal pain, dizziness, somnolence, tremor, edema, diplopia, blurred vision
Warnings: hyperammonia (TX: carnitine in symptomatic adults or lactulose), hypothermia, dose-related thrombocytopenia (increased bleeding risk), multiorgan hypersensitivity rxns (DRESS)
CI: hepatic disease, urea cycle disorder, prophylaxis of migraine in pregnancy, certain mitochondrial disorders if <2 yo
BBW: hepatic failure (usually during first 6 months, children <2 yo and pts w/ mitochondrial disorders), fetal harm (neural tube defects and decreased IQ scores), pancreatitis
Monitoring: LFTS (baseline and frequently in first 6 months), CBC w/ differential (especially PLTs), serum levels, serum ammonia
Valproate: DDIs
Valproate = weak inhibitor of CYP2C9 and UGT, minor substrate of 2C19 and 2E1, and can displace drugs from protein-binding sites
Increases levels of: lamotrigine (USE lower starting dose), phenobarbital, phenytoin, warfarin, and zidovudine
Salicylates: displace valproate from albumin, increasing levels
Drugs that decrease valproate levels: carbapenems, estrogen-containing contraceptives
Topiramate: use can lead to hyperammonemia w/ or w/o encephalopathy
Lacosamide:
-Brand
-MOA
-ROA
-TX
-AVEs
-Warnings
-Monitoring
-DDIs
Brand: Vimpat
MOA: not fully known, may decrease Na channels
ROA: PO, injection
TX: narrow-spectrum anticonvulsant (focal seizures)
AVEs: dizziness, HA, diplpia, blurred vision, ataxia, tremor. euphoria (CV substance)
Warnings: prolongs PR interval (increased arrhythmias risk), multiorgan hypersensitivity rxn (DRESS), syncope, dizziness, ataxia
Monitoring: ECG (baseline and steady state) in at-risk pts
DDIs: caution w/ other drugs that prolong PR interval (beta-blockers, CCBs, digoxin) –> AV block and bradycardia risk
Carbamazepine:
-Brand
-MOA
-ROA
-TX
-Therapeutic range
Brand: Tegretol, Tegretol XR
MOA: inhibits Na channels
ROA: PO
TX: narrow spectrum anticonvulsant (focal seizures), bipolar disorder, trigeminal neuralgia
Therapeutic range:* 4-12 mcg/mL*
Carbamazepine:
-AVEs
-Warnings
-CI
-BBW
AVEs: dizziness, drowsiness, ataxia, N/V, pruritus, photosensitivity, blurred vision, rash, increased LFTs, alopecia, renal impairment
Warnings: hypersensitivity rxn (increased in pt w/ HLA-A*3101 allele), multiorgan hypersensitivity rxns (DRESS), hyponatureamia (SIADH - increases antidiuretic hormone), hypothyroidism, increasd IOP, cardiac conduction abnormalities, liver damage, fetal harm
CI: myelosupression, hypersensitivity to TCAs, use of MAOIs within 14 days, use with nefazodone or NNRTIs (substrates of CYP3A4)
BBW:
-Serious skin rxns (SJS/TEN) –> HLA-B*1502 allele testing required for Asian descent prior to starting
-Aplastic anemia and agranulocytosis –> D/C if significant myleosuppression occurs
Carbamazepine:
-Monitoring
-DDIs
Monitoring: CBC w/ differential (including PLTs) prior to start during, LFTs, rash, eye exam, thyroid function tests, serum Na, renal fxn
DDIs: autoinducer that decreases levels of its own and others
-Strong inducer of CYP3A4, P-gp, and others –> can decrease levels of many drugs including aripiprazole, levothyroxine, warfarin, hormonla contractives (recommended to use NON-hormonal conctraceptive)
-Major CYP3A4 substrate: caution with strong inhibitors/inducers
-Do NOT use w/ nefazodone or NNRTIs
-Suspension should NOT be taken with other liquids (precipitates)
Compare oxcarbazepine to carbamazepine
**What is the brand name of oxcarbazepine?
- Structurally similar (CI if hypersensitivity to eslicarbazapine)
- Consider testing HLA-B1502 allele in Asian descent*
- Similar AVEs: skin rxns, hyponatremia
-No agranulocytosis warning - DDIs: NOT an autoinducer, weak CYP3A4 inhibitor and CYP2C19 inhibitor (non-hormonal contraceptive also recommended, caution with strong CYP3A4 inducers)
Brand: Trilleptal
Phenytoin:
-Brand
-MOA
-ROA
-TX
-Therapeutic range
-IV to PO ratio
Brand: Dilantin, Dilantin Infatabs
MOA: inhibits Na channels
ROA: PO, IV
TX: narrow-spectrum anticonvulsant (focal seizures)
Therapeutic range:
-Total level: 10-20mcg/mL
-Free level: 1-2 mcg/mL
IV to PO ratio: 1:1
Phenytoin:
-AVEs (chronic and toxic)
-Warnings
-CI
-BBW
-Monitoring
AVEs:
-Chronic: gingival hyperplasia, heptatoxicity, hair growth, morbilliform rash (measles-like rash), peripheral neuropathy, increased BG, metallic taste, connective tissue hyperplasis
-Toxicity: nystagmus, ataxia, diplopia/blurred visoin, slurred speech, dizziness, somnolence, lethargy, confusion, delirium
Warnings:
-Extravastion that can lead to purple glove syndrome (edema, pain, and bluish discoloration of skin that may lead to tissue necrosis)
-Avoid in pt w/ positive HLA-B1502 test* and had severe rxn w/ carbamazepine
-Multiorgan hypersenstiivty rxns (DRESS), fetal harm, bradycardia, skin rxns (SJS/TEN), blood dyscarsias, cardiac arrest, hepatic and renal impairment, hypothyroidism
CI: previous hepatotoxicity from phenytoin
BBW: infusion-related hypotension and cardiac arrhythmias
-phenytoin IV administration rate should NOT exceed 50mg/min
-fosphenytoin IV (Cerebyx; prodrug of phenytoin): should NOT exceed 150mg PE/minute or 2mg PE/kg/min
Monitoring: serum concentrations, LFTs, CBC w/ differential
-IV: continuous cardiac ECG, BP, and HR; respiratory fxn
Phenytoin:
1. DDIs
- Administration consideratoins: IV, NG-tube, and IV fosphenytoin
- Phenytoin correction equation
- Phenytoin equivalents (PEs) - conversion to fosphenytoin
- DDIs: phenytoin and fosphenytoin
-Strong inducers of several enzymes which will decrease concentraton of many drugs including anticonvulsants, contraceptives, and warfarin –> use non-hormonal contraceptive
-High protein binding and can displace other highly protein-bound drugs
- Administration
-IV phenytoin: do NOT exceed 50mg/min; requires a filter; dilute in NS (stable for 4 hrs, do NOT refrigerate)
-NG phenytoin: enteral feedings decrease absorption, hold feedings 1-2 hours before and after administration
-IV fosphenytoin: do NOT exceed 150mg PE/min, lower risk of purple glove syndrome than phenytoin
- Phenytoin correction = [ total phenytoin measured / (0.2 x albumin - 0.1) ]
-Use when albumin <3.5 g/dL and CrCl >/=10mL/min - 1 mg PE (Phenytoin Equivalent) = 1.5mg fosphenytoin
Phenobarbital:
-Brand
-MOA
-ROA
-TX
-Therapeutic range
Brand: Sezaby
MOA:* enhances GABA, an inhibitory neutrotransmitter*
ROA: PO, injection
TX: narrow-spectrum anticonvulsant (focal seizures)
Therapeutic range: 20-40 mcg/mL (adults)
Phenobarbital:
-AVEs
-Warnings
-CIs
-Monitoring
-DDIs
AVEs: physiological dependence, tolerance, residual sedation (hangover effect), somnolence, cognitive impairment, dizziness, ataxia, depression, folate deficiency
Warnings: potential for drug dependency, respiratory depression, fetal harm, paradoxical rxns (hyperactive or aggressive behavior in acute pain or pediatrics), hypotension (IV), serious skin rxns (SJS/TEN)
CI: severe hepatic impairment, dyspnea or airway obstruction, previous addiction to sedative-hypnotics, intrarterial administration
Monitoring: LFTs, CBC w/ differential
DDIs: phenobarbital and prodrug (primidone) are strong inducers of several enzymes including CYP3A4 and P-gp; can significantly decrease hormonal contraceptive (use non-hormonal contraceptives)
Anticonvulsant “cousins”: list the similar AVEs
-Carbamazepine, oxcarbazepine, eslicarbazepine
-Gabapentin, pregabalin
-Topiramate, zonisamide
Carbamazepine, oxcarbazepine, eslicarbazepine: hyponatremia, rash, enzyme induction
-Eslicarbazepine: active metabolite is oxcarbazepine
Gabapentin, pregabalin: weight gain, peripheral edema, mild euphoria
-Primarily for neuropathy pain
Topiramate, zonisamide: weight loss, metabolic acidosis, nephrolithiasis, oligohidrosis/hyperthermia (in children)
Ethosuximide:
-Brand
-MOA
-ROA
-TX
-AVEs
-Warnings
-Monitoring
Brand: Zarontin
MOA: inhibits T-type Ca channels
ROA: PO
TX: absence seizures
AVEs: N/V, abdmonial pain, weight loss, hiccups, dizziness, somnolence
Warnings: serious skin rxns (SJS/TEN), blood dyscrasias, multiorgan hypersenstivitiy rxn (DRESS)
Monitoring: LFTs, CBC w/ differential, urinalysis, PLTs, rash, trough serum concentration
Other Miscellaneous Anticonvulsants:
1. What is felbamate’s BBW?
- What is fenfluramine’s BBW?
- What is vigabatrin’s BBW?
- What is a CI to zonisamide?
- Felbamate BBW: aplastic anemia
- Fenfluramine BBW: valvular heart disease, pulmonary HTN (REMS)
- Vigabatrin BBW: permanent vision loss
- Zonisamide CI: hypersensitivity to sulfonamides
Anticonvulsant usage in pregnancy
-Teratogenic: clonazepam, phenobarbital, primidone, phenytoin, fosphenytoin, carbamazepine (neural tube defects), valproic acid (neural tube defects)
-Preferred (least risk): levetiracetam, lamotrigine
-Many anticonvulsants reduce efficacy of hormonal contraceptives –> use non-hormonal
-Folate supplementation for women of childbearing age
-Anticonvulsant levels can decline during pregnancy (may need dose increase) and increase during postpartum (may need dose decrease)
Anticonvulsant usage in children
-Concerns of CNS depression and cognitive difficulties (children can outrow epilpesy –> continue to monitor need for medication)
-Use easier formulations (lamotrigine ODT or chewable tablets, levetiracetam ODT or oral solution)
-Topiramate, zonisamide: can cause reduced sweating (hypohidrosis) –> limit sun exposure to avoid hyperthermia
-Lamotrigine-induced rash fatality occurs more commonly in children
Diastat Acudial: Dispensing
Diazepam rectal gel - contains two rectal syringes prefilled
- Hold barrel of syringe in one hand w/ cap facing downward and dose window visible
- Use other hand to grasp the cap firmly and turn to adjust dose
- Confirm the correct dose shows in window. Hold the locking ring at the bottom of the syringe barrel and push upward on both sides of the ring. Once locked, the green band should say “READY”, and the syringe cannot be unlocked.
- Repeat steps for the second syringe
