Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
35 Cards in this Set
- Front
- Back
|
Common etiologies of seizures.
|
Stress can cause seizures in those with seizure disorders
Menstruation can cause increased seizure in some women Low trough (even in therapeutic range) Metabolic Disorders |
|
|
What is your target serum level for Phenytoin?
|
Total 10-20
Free 0.5-3 |
|
|
What is the DDI between Phenytoin and OC's?
|
Phenytoin decreases the efficacy of OC's.
You can use an estrogen has has 50 mcg of estrogen or use a second form of birth control if breakthrough bleeding occurs. |
|
|
What is phenytoin's mechanism of action?
|
Sodium Channel Blocker
|
|
|
What is normal albumin?
|
3.5-5.0
Low albumin = High free phenytoin |
|
|
Breakthrough bleeding is the marker of the OC being ineffective.
What are the goals of treatment in seizure disorders? |
Maintain or decrease number of monthly seizures
Minimize adverse drug events Maintain or improve quality of life |
|
|
Phenytoin has non-linear kinetics.
|
Doubling a dose can get you an exponentially higher serum level.
|
|
|
Valproic acid - Phenytoin DDI.
|
Valproic acid will increase Phenytoin levels
Valproic acid is teratogenic - Do not put a women of childbearing age on this! |
|
|
What would you want to add to a female of childbearing age's drug regimen?
|
Folic acid to reduce incidence of birth defects if birth control fails
0.4 mg po daily Supplemental Vitamin D and Calcium b/c AED's can interfere with vitamin D metabolism and are associated with osteomalacia and osteoporosis. |
|
|
How do you monitor Phenytoin therapy?
|
Phenytoin levels (average half life is 24 hours, so check in about a week)
Seizure frequency (seizure diary) Adherence Efficacy Toxicity (SE's = sedation, blurred vision, HA) |
|
|
What would you counsel patients on a patient on Phenytoin therapy?
|
Vitamin D/Calcium - Prenatal vitamin
Use barrier contraception while you assess if breakthrough bleeding with occur Seizure first aid (what to do if you have a seizure) |
|
|
If a patient is not having seizures but is having side effects, what is your course of action?
|
Lower the phenytoin dose and start a second AED immediately.
or Add the second AED and wait until it is therapeutic to lower the phenytoin dose. |
|
|
If considering a second AED, what are your options and what is your thought process?
|
Lamotrigine is a good choice
Topiramate Valproic acid - avoid in females of childbearing age Phenobarbital ***All of these cause more cognitive effects like sluggishness*** |
|
|
Lamotrigine - OC DDI
|
OC's decrease Lamotrigine levels
Increase Lamotrigine dose |
|
|
Phenytoin - Lamotrigine DDI
|
Phenytoin induces Lamotrigine metabolism via non-CYP mechanism
|
|
|
What drugs do you want to avoid in a patient with an abnormal hepatic panel?
|
Valproic acid - Can cause acute hepatic failure
You can consider Carbmazepine, Levetiracetam, Phenytoin, but you want to monitor levels. |
|
|
What drugs are renally eliminated?
|
Lamotrigine
Levetriacetam Gabapentin ***Not a contraindication in impaired liver function, but need to monitor levels and adjust dose*** |
|
|
What drugs would you avoid if your patient was concerned with weight gain?
|
Pregabalin
Valproic acid Topiramate - weight loss!!! |
|
|
What drug would you avoid if a patient developed a rash while on phenytoin?
|
Carbamazepine - higher incidence of rash - don't necessarily have to avoid unless it is severe like SJS
|
|
|
What factors favor successful withdrawal of AEDs?
|
1) Seizure control within 1 year of onset
2) Seizure free period of > 2 yrs 3) Seizure onset between ages 2 and 35 4) Normal neuro exam, EEG and IQ |
|
|
Relapse rates
|
< 39% in adults
< 32% in children |
|
|
Risk of pregnancy in a patient with epilepsy
|
Increase rate of seizures
Increase rate of miscarriage Low birth weight Many women have normal pregnancy however |
|
|
Specific recommendations on how to withdraw AEDs
|
Remove AED over 6 months one drug at a time.
|
|
|
Teratogenic AEDs
|
Phenytoin - Category D - Defects
Lamotrigine - Folate deficiency associated defects - Category C Valproate |
|
|
If Phenytoin is dc'ed what would happen to Lamotrigine level?
|
It would increase because Phenytoin is an inducer and if you take it away the other drug will increase.
|
|
|
When do you expect to see a relapse if an AED is discontinued?
|
Within a year after AED withdrawal. After this time your risk if much less of relapse.
|
|
|
Treatment of absence seizures.
|
Ethosuximide - Fewest side effects
Lamotrigine Valproic acid |
|
|
Children require higher doses because children have a higher rate of metabolism. This was in reference to a 13 year old.
|
If the patient was 18 yo, she said she would probably go with the same dose as an adult.
|
|
|
Important points to counsel on in Ethosuximide
|
N/V
|
|
|
Lamotrigine
|
Diplopia
Ataxia HA Rash DDI - OC's |
|
|
Valproic acid
|
N/V
Weight gain Thrombocytopenia, Impaired platelet aggregation DDI (Not with OC) |
|
|
Counseling with Carbamezipine.
|
Visual disturbances
|
|
|
Carbamazepine counseling
|
Take with food
Visual disturbances Don't drink alcohol Can't drive Seizure first aid (Gently help them to the floor, remove harmful objects, afterwards move them on their side so they don't choke, do not put anything their mouth, do not leave them alone afterwards) Drug interactions |
|
|
Monitoring
|
WBC's
AMC Side effects DDI Carbamazepine levels (Auto-induction around day 3-5 and completed in 3-4 weeks. You want to check level in 2-3 weeks) |
|
|
If the patient is experiencing side effects (nausea, vomiting) while on Carbamazepine.
|
This can be caused by either GI irritation in which switching to the CR formulation would help. Or it could be caused by a brain stem defect in which switching to the CR formulation would not help)
|
