AEDs Flashcards
Ethosuximide
- MOA: inhibits Ca++
- Indications: tx of absence seizures
- ADRs: Hyperactivity/psychotic behaviors
Gabapentin
- MOA: analog of GABA
- Indications: Adjunct for seizures, PHN, RLS
- Interactions: not metabolized
- ADRs: somnolence/dizziness
- Pearls: may exacerbate myoclonic seizures, must taper to avoid withdrawal sx (anxiety, insomnia, pain, etc)
Pregabalin
- MOA: modulates calcium–> affects release fo glutamate, NE, Substance P*
- Indications: fibromyalgia, peripheral neuropathy (DM/PHN), RLS, off-label GAD
- ADRs: weight gain (bad for fibro), euphoria with withdrawal (C-V)
- Pearls: same as gabapentin
Phenobaribtal
- Uncommon drug
- MOA: Binds GABAa and hyperpolarizes neuron
- Autoinducer
- ADR: sedation
Clobazam
- MOA: see BZD
- Used in Lennox-Gastaut
- ADR: like benzos, but less sedating
Clonazepam
- MOA: see BZD
- Used in Lennox-Gastaut
Tiagabine
- MOA: enhances GABA
- ADR*: new-onset seizures and status epilepticus have been associated when taken for unlabeled indications (ex. bipolar, anxiety, neuropathic pain)
Vigabatrin
- MOA: increases CNA GABA
- Indications: monotherapy for infantile spasms (orphan drug)–> effective for infantile spasms r/t tuberous sclerosis
- ADRs*: irreversible retinal toxicity
Perampanel
- MOA: AMPA antagonist (glutamate receptor)
- ADRs: euphoria/abuse potential (C-III), BBW* for homicidal ideation/threats
Valproate
- MOA: many, main one is inc GABA
- Indications: Most are not for seizures–> bipolar and migraine prophy
- Monitoring: Serum ammonia
- Interactions: inhibits multiple enzymes (including 2D6)–> careful with lamotrigine
- ADRs: Lethargy (hyperammonemia), Parkinsonism, weight gain, **hepatotoxicity/hepatic failure (kids)
- MOST TERATOGENIC AED- ONLY USE IF PT HAS SEIZURES AND ABSOLUTELY NEEDS DRUG
Topiramate
- MOA: enhances GABA at nonBZD GABAa receptor
- Indications: Lennox-Gastaut, migraine prophy, chronic weight mgmt
- Monitoring: HCO3 q2-4 mo
- Systemic ADRs: wt loss, olioghidrosis/hyperthermia, heat stroke (kids), metabolic acidosis/kidney stones
- Neurotoxic ADRs: “Dopamax,” blurred vision, eye pain
- Teratogen
Felbamate
- Indications: Lennox-Gastaut
- ADRs*: fatal aplastic anemia and hepatic failure–> written consent required prior to therapy
Levetiracetam
- Indications: prevention after TBI/NS
- ADRs: suicidality, depression, agitation, aggression, anxiety, etc
Brivaracetam
- Analog of levetiracetam
- ADRs: suicidality, depression, C-V
Cannabidiol
- Dravet syndrome and Lennox-Gastaut
- Put some in your old fashioned
Drug-Induced Seizures
- Bupropion
- Tramadol
- Antipsychotics (clozapine/chlorpromazine)
- CPHs, PCNs, FQs
- Tx: d/c drug and IV/IM lorazepam
AEDs and Suicide
-Must screen for depression/anxiety before initiation of AED
AEDs and Bone Density
- Prolonged used ass with decreased bone density
- Phenytoin, CBZ, phenobarbital, valproate
AEDs and Child-Bearing Women
- may induce OCPs
- All women on AEDs of child-bearing age should be on 1 mg folic acid
- Refer for preconception counseling
- VALPROATE CATEGORY X FOR DISORDERS OTHER THAN SEIZURE
AEDs and generic substitution
- Bioequivalence with generics may not be true with epilepsy
- Pearl: if seizure occurs in otherwise controlled patient, ask about recent generic substitution
Carbamazepine
- chemically related to amitriptyline (cyclobenzaprine)
- treatment of chronic pain syndromes (e.g. trigeminal neuralgia)
- acute manic or mixed episodes of bipolar I disorder
CBZ side effects / ADRs
- may make absence or myoclonic seizures worse
- do NOT store in humid conditions (concretion)
- monitor concentration (autoinduction)
- common neurotoxic ADRs
- common ADR: SJS, vit D def, SIADH
- severe ADR: leukopenia, aplastic anemia
- teratogen: neural tube defects
Oxcarbazepine / Eslicarbazepine
- similar chemical structure to carbamazepine
- may make absence or myoclonic seizures worse
- ADRs: 20-30% of pt w/skin rxn to CBZ may react to Oxcarbazepine; more hyponatremia than CBZ (SIADH)
Fosphenytoin compared to phenytoin
- Fosphenytoin: phenytoin prodrug - faster admin, less complications, safer than phenytoin (esp w/cardiac), no in-line filter required
Phenytoin / fosphenytoin
- prevention of “early” seizures following TBI/NS*
- monitor levels (autoinduction)
What’s “a huge pearl to remember” regarding phenytoin toxicity d/t high concentration?
Conduct EOM
- lateral nystagmus
- middle nystagmus
Must put patient on cardiac monitoring asap.
Can lead to death .
Lamotrigine
- tx newly dx absence seizures**
- may be less effective than ethosuximide / VPA, but better tolerated
- LGS
- maintenance tx of bipolar disorder
What’s the most important interaction to remember with lamotrigine?
Do not ever prescribe VPA and lamotrigine together - will induce SJS.
VPA increases lamotrigine concentration > 2x
Phenytoin / fosphenytoin ADRs
- ADRs: gingival hypertrophy, rash, drug fever
- IV infusion ADR: venous irritation / thrombophlebitis (minimize w/fosphenytoin)
- teratogen: fetal hydantoin syndrome (FLK Paxton)
Lamotrigine ADRs
- rash: SJS, TEN
- Aseptic meningitis*
Lacosamide
- rhythm / ECG monitoring (baseline ECG)
- interactions: concomitant PR-prolonging drugs (b-blocker, CCB)
Lacosamide ADRs
- euphoria (schedule V)
- small increase in mean PR interval
Zonisamide
- sulfonamide derivative
- used for “really weird seizures”
- monitor bicarb!!
Zonisamide
- oligohidrosis, hyperthermia, heat stroke
- metabolic acidosis, renal stones possible - from increased bicarb excretion
Rufinamide
- LGS
- monitor ECG - additive effect w/drugs that shorten QT interval
Ezogabine
- ECG monitor - concomitant QT prolonger interactions
- ADRs: psychiatric/hallucinations; urinary retention*; euphoria (schedule V)
