Neuropsych Meds- AEDs Flashcards
What should be done in the first five minutes of a seizure?
- ABC Stabilization
- Check BG
- Get labs and check for abnormalities
In the first five minutes of a seizure, a blood sugar should be treated at or below ___mg/gl?
If <60mg/dl
What is treatment for blood sugar <60mg/dl for a seizing patient?
Adult: Thiamine 100mg with 50ml D5W
Child>2yo: 2ml/kg D25 IV
Child<2yo: 4ml/kg D12.5 IV
What is the first phase of status epilepticus?
5-20 mins long seizure
What is second phase of status epilepticus?
20-40 mins long seizure
What is third phase of status epilepticus?
40-60 mins long seizure
What is first phase treatment for Status epilepticus?
- x1 Midazolam IM (>40kg=10mg, 13-40kg=5mg)
- Lorazepam IV (can repeat once) 0.1mg/kg (max 4mg)
- Diazepam IV (can repeat once) 0.15-0.2mg/kg (max 10mg)
If midaz, loraz, or diazepam are not available, what can also be given for first phase?
- Phenobarb IV 15mg/kg x1
- Diazepam PR 0.2-0.5mg/kg (max 20mg)
- Nasal or buccal midazolam
If status epilepticus has progressed to second phase, what can be used to treat?
- Fosphenytoin IV 20mg/kg (max 1500mg)
- Valproic Acid IV 40mg/kg (max 3000mg)
- Keppra IV 60mg/kg (max 4500mg)
If fosphen, VPA, or keppra not available in phase 2, what can also be used?
Phenobarb IV 15mg/kg (if not previouslt used)
T/F: In second phase status epilepticus, fosphenytoin is the drug of choice based on research evidence?
False; no evidence based first choice. Can use any of the choices available (keppra, VPA, fosphenytoin)
If status epilepticus has progressed to third phase, what can be used to treat?
No clear evidence, but choices include:
- Repeat any second line therapy
- Anesthetic doses of thiopental, midazolam, pentobarbital, or propofol
T/F: If anticonvulsant medication is held or stopped, there is only a risk of seizures if patient has or has previously had epilepsy?
False; even if patient has not had a seizure and that medication is not specifically prescribed for seizure. there is still a risk
What are the 7 different MOA for anticonvulsant therapy?
- Sodium channel blockade
- Calcium channel blockade
- GABA enhancers
- Glutamate blockers
- Carbonic anhydrase inhibitors
- Sex hormones
- Synaptic vesicle protein 2A (SV2A)
What are examples of Sodium channel blockers?
- Carbamazapine (Tegretol,Carbatrol)
- Oxcarbazepine (Trileptal)
- Eslicarbazepine (Aptiom)
- Phenytoin/fosphen (Dilantin)
- Lamotrigine (Lamictal)
- Zonisamide (Zonegran)
- Lacosamide (Vimpat)
What are the four uses for Carbamazepine?
- Partial and generalized seizures (less often for seizures)
- Mood stabilizer
- Neuropathic pain
- Trigeminal neuralgia (1st line therapy)
T/F: Carbamazepine is most frequently prescribed for seizures compared to its other uses?
False
What is unique about the pharmacokinetics of Carbamazepine?
- Induces its own metabolism
- CYP3A4 inducer and substrate
- 75-85% protein bound
- Has active metabolite
If carbamazepine induces its own metabolism, how does that affect its administration?
Will have increasingly higher dosage requirement with time
Side effects of carbamazapine?
- Dizzness, ataxia, diplopia, nausea.
- Aplastic anemia, agranulocytosis, thrombocytopenia
- Stevens Johnson
- Increased LFTs
- Hyponatremia
Which side effect is seen in nearly all patients taking carbamazapine?
Hyponatremia
How is oxcarbazepine (Trileptal) different than carbamazapine?
- Not self inducing
- Better tolerated
- Fewer drug interactions
- Slightly less side effect risk
How is eslicarbazepine (Aptiom) different than carbamazapine?
- Its a prodrug broken down to S-licarbazepine
- Needs renal dose adjustment
- Even less side effects when compared to oxcarbazepine/carbamazapine
What anticonvulsant has non-linear pharmacokinetics?
Phenytoin/fosphenytoin (Dilantin)
What does non-linear pharmacokinetics mean?
When you increase the dose of the medication, the serum levels do not go up in a normal linear line. They can go up exponentially and are different for each patient. Its zero order, so the eliminates a certain amount every hr, independent of drug concentration in the body
The non-linear pharmacokinetics of Dilantin can pose a specific problem when?
When changing from IV to PO or PO to IV
What are two adverse side effects that can be seen with long term dilantin use?
- Gingival hyperplasia
2. Osteoporosis/Bone marrow hypoplasia
What are side effects of dilantin?
- Arrythmias, CV depression, HoTN
- Ataxia, nystagmus, N/V
- Blood dyscrasias
- Vit K and folate deficiency
- Osteoporosis, rash
T/F: Dilantin is one of the few drugs that is recommended in pregnant women?
False; can cause cleft palate, cleft lip, CHD, slowed growth rate, mental deficiency
How is lamotrigine (Lamictal) similar to carbamazapine pharmacokinetically?
It can autoinduce, but only at high doses
If not tapered correctly, lamotrigine (Lamictal) has a high risk of causing ________ when used in combo with VPA
Stevens Johnson reaction
Does lamotrigine (Lamictal) have active metabolites?
No
What are the two most common CNS related symptoms seen with lamotrigine (Lamictal)?
Psychosis and insomnia
so risk of post-op delirium, agitation with Lamictal
What drug does lamotrigine (Lamictal) have a an interaction with?
Valproic Acid. Causes steven-johnson syndrome
What drug does zonisamide have an interaction with?
None. No drug interactions
What side effect does zonisamide cause specifically in children?
Oligohidrosis
What two medications is it common to see “psycho-motor disconnect” (slowed down thought process)?
Zonisamide and Topiramate
aka “mental slowing”
Side effects of zonisamide (zonegran)?
- Dizziness, ataxia, HA, confusion, speech abnormalities, mental slowing,
- Anorexia or weight gain
- Irritability, tremor
- Renal stones in 1.5% pts
- Rash, skin reactions
Half lives of Phenytoin, lamotrigine, zonisamide, lacosimide?
Phenytoin= variable 7-42hrs
Lamotrigine=24-41hrs
Zonisamide=60hrs
Lacosamide=13hrs
Pros/Cons Lacosamide (Vimpat)?
Pros:
Minimal protein binding
No induction/inhibition CYP
Nice side effect profile
Cons:
Expensive
Pregnancy Category C
What are the four categories of GABA Agents?
- GABA Agonists
- GABA Reuptake Inhibitors
- GABA Transaminase Inhibitors
- GABA “Other” (Not agonists, but enhance the GABA activity
Of all the benzos, what has the most significant withdrawal risk?
Clobazam (Onfi)
its only use is actually for seizures, not anxiety like the other benzo’s
What drug is metabolized to phenobarbital and what is it used for?
Primidone is a prodrug that is metabolized to phenobarbital and it is seen with patients with musculo-skeletal disorders.
What drug classes/drugs fall under GABA Agonists?
- Benzos
- Phenobarbital
- Primidone (Mysoline)
What drug classes/drugs fall under GABA Reuptake Inhibitors
Tiagabine (Gabitril)
What drug classes/drugs fall under GABA Transaminase Inhibitors?
Vigabatrin (Sabril)
What drug classes/drugs fall under GABA “Others”?
- Gabapentin (Neurontin)
- Pregabalin (Lyrica)
- Valproate (Depakote)
What is REMS?
Medication Monitoring system. Special pharmacies are the only distributors and the patient needs to be monitored very closely
What is gabapentin mostly used for?
More often used for neuropathy than seizure control
Pharmacokinetics of Gabapentin?
- Not protein bound
- Not metabolized
- No induction
- Excreted completely unchanged in kidneys
- No PK Drug interactions
Pre-operative Gabapentin does what two things?
- Reduces opiate requirements
2. Increased post op sedation
Side effects of Gabapentin?
Overall very, very mild side effects- rash, neutropenia, somnolence, dizziness, ataxia, fatigue, nystagmus, diplopia, HA, tremor, N/V (all only really seen at high doses)
What is pregabalin (Lyrica)’s most common use?
Diabetic neuropathy
considered to be “Neurontin like”, but has more sedation and ataxia compared to gabapentin
What are two other (less common) uses for Pregabalin (Lyrica)?
Seizures and anxiety
MOA of Pregabalin(Lyrica)?
GABA Analogue, binds alpha-2 and delta receptor sites which reduces release of excitatory neurotransmittors via Ca++ currents
Pharmacokinetic considerations for pregabalin(Lyrica)?
- Half life 6 hours
- Food reduces absorption
- No plasma protein binding
4, 90% unchanged in urine - No notable PK drug interactions
Pregabaline (Lyrica) ADRs?
- Dizziness, drowsiness, blurred vision, difficulty concentrating
- Dry mouth
- Edema, rare angioedema
- Weight gain
Post-operative considerations for Pregabalin (Lyrica)?
Post-op delirium and confusion risk
T/F: There are several different forms of Valproic Acid (VPA), and they all have different effects and side effects to remember?
False; many different forms, but all have same SE/effects
How would a low albumin effect VPA?
It is 85-90% protein bound and low protein could have higher risk of toxicity
This can occur in trauma, burn, liver dz, malnutrition, hypoalbuminemia
Where is VPA metabolized?
Liver
If VPA at toxic levels d/t overdose, what should be done?
Stop the medication and within 2.5 days, levels will fall to safe levels
b/c half life is about 16hrs
Three main SEs to watch for with VPA?
- Hepatoxicity (highest risk in children, accompanied with rare but fatal pancreatitis)
- Thrombocytopenia (risk of bleeding)
- Hyperammonemia (may present as liver failure/very confused patient)
Emily harped on all 3 of these
T/F: Though VPA is associated with drug interactions, it is safe for pregnant women?
False; it is associated with drug interactions through inhibition of oxidation and glucoronidation pathways, but it is NOT recommended for parturients (cat D-X)
VPA can cause lower IQ kids
Why is felbamate rarely used in the US?
High risk of aplastic anemia and fatal hepatic failure
Three main uses of topiramate (Topamax)?
- Alcohol withdrawal
- Migraine Prophylaxis
- Seizures
MOA of Topiramate (Topamax)?
- Sodium Channel blocker
- GABA enhancement of unknown mechanism
- AMPA Inhibition (part of NMDA, so inhibits glutamate)
- Weak carbonic anhydrase inhibitor
(Basically, global potential suppression. It “kind of hits all the different sites”, per Emily”
T/F: Topiramate (Topamax) has many drug interactions, but compared to many other drugs, it has a good side effect profile?
False; It has not drug interactions
What is the side effect profile of Perampanel?
- BB Warning for life threatening psych/behavioral effects
- Dizziness (43%-Most common)
high risk of SE, so it’s not used a lot. If on it, risk of post-op agitation and delirium
MOA of levetiracetam (Keppra)?
- Possibly related to synaptic vesicle protein 2A (SV2A)= important for the Ca++ dependent neurotransmitter vesicles ready to release their content
- Reduces bicuculline induced hyperexcitability
- Inhibits Ca++ release from IP3-sensitive stores
Does keppra play nicely with other drugs?
Yes, yes it does
Levetiracetam ADRs?
- Somnolence, asthenia, dizziness, HA, convulsion, cognitive impairment, pain
- Accidental injury
- Infection (URI, pharyngitis, flu-like symptoms)
Which GABA Analog has significant withdrawal risk?
Baclofen
MOA Baclofen?
- Presynaptic Hyperpolarization
A. Reduced Ca++ influx
B. Reduced glutamate release
C. Decreased alpha-motor neuron activity - Post-synaptic activation
A. Increased K+
B. Hyperpolarization - Substance P Inhibition in spinal cord to reduce pain (Emily mentioned this one as the big one)
What are withdrawal symptoms of baclofen?
- Hallucinations
- Fever
- Agitation
- Tremor - significant
- Tachycardia
- Seizures