A seizure occurs when
excitatory neurons produce a sudden urge of electrical activity in the brain
Seizures can be caused by
temporary conditions such as fever (common in children), infection, alcohol withdrawal, hypoglycemia or electrolyte abnormalities
What does it mean when it says a medication "can lower the seizure threshold"
meaning it can make a person more susceptible to a seizure (these meds should be avoided in people with a history of seizures)
What is epilepsy
a chronic seizure disorder
Most common test used to diagnose epilepsy, records electrical activity in the brain
electroencephalogram (EEG)
(can show abnormal patterns even when the patient is not having a seizure)
Drugs that can lower the seizure threshold
bupropion, clozapine, theophylline, varenicline, carbapenems, lithium, meperidine, penicillins, quinolones, tramadol, acyclovir, valacyclovir, cephalosporins
Define focal seizures
start on one side of the brain but can spread to the other side
(further classified)
Define generalized seizures
start on both sides of the brain
Define focal aware seizure
no loss of consciousness
Define focal seizure with impaired awareness
the patient experiences loss of consciousness
Define clonic symptoms
sustained rhythmical jerking movements
Define atonic symptoms
limp or weak muscles
Define myoclonus symptoms
muscle twitching
Define tonic symptoms
rigid or tense muscles
Generalized seizures with non-motor symptoms are called
absence seizures (typically start as staring spells)
Define status epilepticus (SE)
a seizure that lasts 5 mins or more
SE treatment phases
stabilization phase --> initial treatment phase --> second treatment phase
What medications are given in the initial treatment phase of SE (5-20 mins)
IV lorazepam or IM midazolam
alternatives: rectal diazepam (Diastat), intranasal or buccal midazolam
What medications are given in the second treatment phase of SE (20- 40 mins)
IV fosphenytoin, valproic acid, levetiracetam
(phenobarbital if others are unavailable)
Non-drug and alternative options for chronic seizure treatment
medical marijuana, ketogenic diet, vagal nerve stimulation or surgical intervention
What is the name of a FDA approved smart watch that monitors seizures in adults and children 6 years of age and older
Embrace2
cannabis-derived medications approved by the FDA to treat rare forms of epilepsy
Cannabidiol or CBD (Epidiolex)
What is a ketogenic diet
high fats, normal protein and low carbohydrates (4:1 ratio of fats to combined protein and carbohydrates)
MOA of BZDs and valproic acid
increase GABA
MOA of phenobarbital
enhance/potentiate GABA effect
MOA of levetiracetam
Ca channel blocker and increase GABA
MOA of ethosuximide
T-type Ca channel blocker
MOA of pregabalin and gabapentin
Ca channel blocker
MOA of oxcarbazepine
Na and Ca channel blocker
MOA of carbamazepine, lamotrigine, phenytoin/fosphenytoin, topiramate
Na channel blockers
Brand name of lamotrigine
Lamictal
If lamotrigine is discontinued for ≥ 5 half-lives (> 6 days for most patients), what should happen?
the initial dose titration must be restarted
Side effects of lamotrigine
alopecia, rash (SJS/TEN), blurred vision, ataxia
If the lamotrigine starter kit is orange, what dose is it?
standard starting dose
If the lamotrigine starter kit is blue, what dose is it?
lower starting dose
If the lamotrigine starter kit is green, what does is it?
higher starting dose
Brand name for levetiracetam
Keppra
IV:PO ratio levetiracetam
1:1
Brand name for topiramate
Topamax
Brand name for topiramate ER
Trokendi XR
Topiramate can decrease the INR in patients on
warfarin
(can also decrease hormonal contraception)
Side effects of topiramate
difficulty with memory, concentration, attention, weight loss, anorexia
Brand name for divalproex
Depakote
Therapeutic range for divalproex
50-100 mcg/mL
Depakote is also used for
bipolar disorder and migraine prophylaxis
Divalproex is a derivative of what
valproic acid
Side effects of valproic acid/divalproex
hyperammonemia, thrombocytopenia, alopecia
Brand name of lacosamide
Vimpat
(it is a C-V)
Brand name of carbamazepine
Tegretol
Therapeutic range for carbamazepine
4-12 mcg/mL
What medication is an autoinducer and will decrease its own levels
carbamazepine
When using carbamazepine, oxcarbazepine and phenytoin in patients of Asian descent, what should they be tested for
HLA-B*1502 allele
Brand name of oxcarbazepine
Trileptal
Side effects of carbamazepine
SIADH, DRESS reactions, hypothyroidism
Brand name for phenytoin
Dilantin
Therapeutic range for phenytoin (total level)
10-20 mcg/mL
Therapeutic range for phenytoin (free level)
1-2.5 mcg/mL
Phenytoin IV administration rate should not exceed
50 mg/min
Fosphenytoin IV rate should not exceed
150 mg PE/min or 2 mg PE/kg/min
Warnings for phenytoin/fosphenytoin
extravasation (leading to purple glove syndrome), DRESS
Side effects of phenytoin dose-related toxicity
nystagmus, ataxia, diplopia,/blurred vision, slurred speech, dizziness, somnolence, lethargy, confusion
prodrug of phenytoin
fosphenytoin
chronic side effects of phenytoin
gingival hyperplasia, hair growth, hepatotoxicity, morbilliform rash (measles-like), increased BG, peripheral neuropathy
Brand name of fosphenytoin
Cerebyx
Brand name of phenobarbital
Sezaby
(C-IV)
Therapeutic range of phenobarbital (adults)
20- 40 mcg
Therapeutic range of phenobarbital (children)
15- 40 mcg/mL
What is the prodrug of phenobarbital
Primidone
Brand name of cenobamate
Xcopri
(C-V)
What is a contraindication for zonisamide
hypersensitivity to sulfonamides
Brand name for zonisamide
Zonegran
the metabolism of phenytoin can become saturated when
there are no enzymes left to metabolize the drug, a small increase in the dose can lead to a large increase in the drug concentration
What kinetics does phenytoin have
michaelis-menten kinetics (also called saturable kinetics)
When should you adjust the total level of phenytoin
when albumin is < 3.5 g/dL and CrCl ≥ 10 mL/min
phenytoin correction calculation
total phenytoin measured/ (0.2 x albumin) + 0.1
AEDS can cause bone loss and
increase fracture risk
(all patients on AEDS should be on calcium and vitamin D)
Women of childbearing age on AEDs should receive
daily folate supplementation
What doses does diastat come in
2.5, 10 and 20 mg
Brand name of oxcarbazepine ER
Oxtellar
How to take Oxtellar ER
on an empty stomach at least one hour before or two hours after food