26 - Seizures/Epilepsy Flashcards
non-pharms for seizure
- avoid sleep deprivation
- keep alcohol consumption to a minimum
- avoid cocaine and amphetamines
- ketogenic or atkins diet may decrease seizure frequency
- yoga or mildfulness-based therapy may help
if sensitive to phenytoin, avoid _____
carbamazepine
first line for absence seizures
ethosuximide
What is primidone’s active metabolite?
phenobarbital
Definition of epilepsy?
-either 2 unprovoked seizures occurring more than 24 hours apart, 1 unprovoked seizure at a high (>60%) probability of further seizures over the next 10 years or 1 unprovoked seizure and a clearly identifiable epilepsy syndrome
An aura indicates the onset of what type of seizure?
focal (partial) seizure
What is a simple partial seizure?
- focal seizures without impairment of awareness
- usually brief, less than 60 seconds
What is a complex partial seizure?
focal seizures with impairment of awareness
-usually last 1-2 mins
List the 4 types of generalized seizures
- Absence
- Generalized tonic-clonic
- Atonic
- Myoclonic
Describe an absence seizure (petit-mal)
- usually lasts only 5-10 seconds
- can recur daily
- no warning signs
- onset in childhood
Describe a generalized tonic-clonic seizure (grand-mal)
- tonic/clonic phases
- can begin as a focal seizure or can involve entire brain at onset
Describe an atonic seizure
- abrupt loss of consciousness and muscle tone
- return to awareness in seconds
Describe myoclonic seizures
-“shock-like” jerks
Which AEDs can we measure serum levels for
phenytoin, phenobarbital, primidone, CBZ, VPA
First choice monotherapy for generalized tonic-clonic
- CBZ
- lamotrigine
- levetiracetam
- phenytoin
- VPA/divalproex
First choice montherapy for absence seizures
ethosuximide
First choice monotherapy for myoclonic and atonic seizures
VPA/divalproex
First choice monotherapy for focal (partial) seizures with or without secondary generalization
- CBZ
- lamotrigine
- levetiracetam
- phenytoin
Women of childbearing age taking an AED should receive what daily supplementation to prevent neural tube defects?
folic acid 1 mg daily
_____ may be better tolerated than CBZ and have similar effectiveness in obtaining long-term seizure freedom
lamotrigine
____ may be superior to lamotrigine and topiramate
VPA
For childhood absence epilepsy, ____ and _____ are similarly effective in preventing seizures and both meds are superior to lamotrigine
ethosuximide and BPA
Ethosuximide is associated with lower rates of ______ difficulties than VPA so it is first choice for childhood absence epilepsy
attention
For patients with traumatic brain injury, AEDs prevent seizures in the first ___ days after the injury but have no effect on development of later seizures
7
What are some dose-related adverse effects of AEDS?
How do you manage them?
- dizziness, sedation, fatigue, cognitive and psychiatric symptoms, nausea
- try reducing the dose or slow release formulation or more frequent administration with lower doses of IR AED
What is an idiosyncratic reaction to AED?
skin rash
Which AEDs are most likely to cause skin rash
phenytoin, CBZ, lamotrigine
When is rash most likely to occur?
within 6 weeks but can occur at any time
If a definite drug rash develops, how do you manage this?
stop AED. Continuation can result in SJS
What type of people are at higher risk for CBZ-associated rash?
Han Chinese descent with certain human leukocyte antigen (HLA) status
*consider checking HLA status in these patients before starting CBZ therapy
AEDs can also cause other idiosyncratic reactions such as ?
hematopoiesis or hepatic toxicity
Long-term use of enzyme-inducing AEDs and VPA have been associated with what?
increased risk fo low bone density and fracture
Pre-pregnancy considerations:
Ideally if patient on COC, how much estrogen should it have if they’re on enzyme inducing AED?
> 50 mcg EE but no COC products currently available with EE > 35 mcg
Pre-pregnancy considerations:
What are some options for women to prevent pregnancy on enzyme inducing AEDs?
- depot shot
- IUD (hormonal and non-hormonal)
- barrier contraception (less effective)
Pre-pregnancy considerations:
Which AED is actually decreased by COCs?
lamotrigine
- levels can be expected to drop by at least 50% after starting COC
- consider doubling lamotrigine dose after starting a COC
If they are pregnant and on an anti-epileptic drug that will not be stopped, how much folic acid and when do they need it?
- Ideally 1mg folic acid daily at least 3 months prior to conception until 12 weeks gestation
- Then from 12 weeks gestation continuation through pregnancy and for 4-6 weeks postpartum or as long as breastfeeding continues, they need folic acid 0.4-1mg daily.
Which AEDs are associated with low rates of teratogenicity?
lamotrigine, levetiracetam and oxcarbazepine
Levels of AEDs can ____ when pregnancy due to increased clearance
decrease
If a pregnant person is controlled on an AED that may cause teratogenic effects do you switch?
No, the risk of congenital malformations is highest in 1st trimester when many women don’t even know they are pregnant
A change in controlled therapy puts person at risk of another seizure which can harm the mom and fetus
What vitamin is routinely given to all newborns of a mom on an AED?
vitamin K bc enzyme-inducing AEDs can potentially increase the degradation of vitamin K in the fetus
Do you still recommend breastfeeding while on AED?
Yes
Infants whose mothers are taking _____ may be sedated
barbiturates
AED levels may _____ after delivery
increase
If a patient is controlled but they are below the serum target range, do you increase the drug.
no - “treat the patient, not the serum level”
Is CBZ a pro drug?
yes
100 mg phenytoin sodium = ___ mg phenytoin base
92
