(6) Neuro & Psych: Mood (4.1-4.4) Flashcards
Does Lithium have a narrow or broad therapeutic index?
Narrow
What are the symptoms of acute Lithium toxicity?
GI Symptoms
What are the symptoms of chronic Lithium toxicity?
(1) Tremor
(2) Ataxia
What endocrine abnormalities are associated with Lithium use?
(1) Hypothyroidism
(2) Diabetes insipidus
Name 2 classes of drugs which increase Lithium levels
(1) Diuretics
(2) NSAIDs
What fetal abnormality is associated with Lithium use?
Ebstein’s anomaly
Other than Lithium and antipsychotics, name 3 drugs used to treat bipolar disorder
(1) Valproate
(2) Carbamazepine
(3) Lamotrigine
Describe Ebstein’s anomaly
Atrialization of right ventricle
(Due to severely incompetent tricuspid valve)
Name 4 broad-spectrum antiepileptics
(1) Valproate
(2) Topiramate
(3) Lamotrigine
(4) Levetiracetam
What type of seizures can be treated with broad-spectrum antiepileptics?
(1) Focal seizures
(2) Generalized seizure
(3) Juvenile myoclonic seizure
(4) Abscence seizures (less so)
MOA: Valproate
(1) Increase inactivated phase of voltage-gated Na+ channels
(2) ↑ CNS GABA levels (somehow)
* (Open basket ∝ Open gate ∴ Closed lid represents drug holding the gate shut)*
Adverse Effects (6) : Valproate
(1) GI distress
(2) Weight gain
(3) Fine tremor
(4) Fatal hepatotoxicity
(5) Pancreatitis
(6) Teratogen
What type of congenital deformity does Valproate cause?
Neural tube defects
(∝ TMP-SMX)
MOA: Topiramate
(1) Increases Na+ channel inactivation
(2) Allosterically activates GABAA receptor
Adverse Effects (5) : Topiramate
(1) Somnolence
(2) Confusion and cognitive-slowing
(3) Weight loss
(4) Urolithiasis
(5) Acute angle-closure glaucoma
* (Treatment must be stopped if acute angle-closure glaucoma presents)*
Which broad spectrum epileptic is most associated with Stevens-Johnson syndrome?
Lamotrigine
(Up to 10% of patients will experience a benign rash)
Adverse Effects (2) : Lamotrigine
(1) Stevens-Johnson Syndrome
(2) Diplopia
Adverse Effect: Levatiracetam
Somnolence
How are antiepileptics metabolized?
Almost universally via CYP450
Name 5 narrow-spectrum antiepileptics
(1) Carbamazepine
(2) Phenytoin
(3) Gabapentin
(4) Vigabatrin
(5) Tigabine
Treatment: Trigeminal neuralgia
Carbamazepine
Adverse Effects (9) : Carbamazepine & Phenytoin
(1) Ataxia
(2) Diplopia
(3) SIADH
(4) Agranulocytosis/Aplastic anemia
(5) CYP450 induction
(6) DRESS syndrome
(7) Teratogen
(8) Stevens-Johnson syndrome
(9) Drug induced lupus
What type of fetal malformations is Carbamazepine associated with?
Neural tube defects
(As well as general fetal dysmorphisms)
Name 4 adverse effects of Phenytoin not present in Carbamazepine
(1) Megaloblastic anemia
(2) Gingival hyperplasia
(3) Hirsutism
(4) Decreased bone density
* (Strong induction of CYP450 system ⇒ ↑ Steroid metabolism ⇒ ↑ Rate of Vit. D inactivation ⇒ Osteopenia)*
What fetal malformations is Phenytoin associated with?
Cleft palate
Define: Status epilepticus
Continuous (≥ 5-30 min) seizure
Treatment: Status epilepticus (acute setting)
IV Benzodiazepine
(Ben’s diner is above the “order status” sign = Benzo first and Phenytoin second)
Treatment: Status epilepticus (maintenance stage)
Phenytoin
(Ben’s diner is above and tow truck below the “order status” sign and the tow truck is below = Benzo 1st and Phenytoin 2nd)
Treatment: Status epilepticus (refractory)
Barbiturate
MOA: Gabapentin
Inhibits voltage-gated Ca2+ channels
(“Gabapentin does NOT bind to GABA receptors. I repeat, Gabapentin does NOT bind to GABA receptors”)
Which anti-seizure medication is effective against neuropathic pain?
Gabapentin
Adverse Effect: Gabapentin
Ataxia
MOA: Vigabatrin
Irreversibly inhibits GABA transaminase
(Notice this is a degradative enzyme rather than ion channel/transmembrane receptor)
MOA: Tiagabine
Inhibits GABA reuptake
What type of seizures are narrow-spectrum anti-epileptics used for?
Focal seizures (and generalized tonic-clonic)
Which antiepileptic is used ONLY for absence seizures?
Ethosuximide
Describe an absence seizure
Sudden momentary lapses in awareness
(Most commonly seen in children)
How do absence seizures manifest on EEG?
3 Hz spikes
(Similarily, Cretuzfeld-Jakob disease shows periodic synchronous sharp wave complexes)
MOA: Ethosuximide
Inhibits thalamic T-type Ca2+ channels
(“If you think about it, thermos even kind of sounds like thalamus!”)
Adverse Effects (2) : Ethosuximide
(1) GI distress
(2) Lethary
Treatment: Absence seizure with occasional tonic-clonic
Valproate
Which 2 broad-spectrum antiepileptics are most effective against absence seizures?
(1) Valproate
(2) Lamotrigine
* (Valproate > Lamotrigine)*
