Anti-Seizure Drugs Flashcards
(51 cards)
What drug is used as 1st line treatment for silent (absence) seizures?
Ethosuximide
What is the mechanism of ethosuximide?
Blocks thalamic T-type Ca2+ channels –> irregular rhythmic cortical discharge of absence attack
What are the major side effects of Ethosuximide?
(EFGHIJ) Ethosuximide causes fatigue, GI distress, headache, itching, Stevens-Johnson syndrome
What do benzodiazepines do & which ones are used for status epilepticus? P.S. what are benzos also used for?
Benzos increase GABAa action - Diazepam and lorazepam - they are also used for eclampsia seizures (first line is MgSO4)
What are the side effects of Benzodiazepines? (4)
Sedation, tolerance, dependence, respiratory depression
What is the mechanism of Phenytoin?
Increase Na+ channel inactivation & decrease release of glutamate; zero-order kinetics (give more –> more effect)
What is the 1st line use of Phenytoin? What is the prophylactic use of Phenytoin?
1st line: tonic-clonic seizure; prophylaxis: status epilepticus
What is the parenteral form of Phenytoin?
Fosphenytoin
What is the acute use of Phenytoin? (2)
Simple & complex partial (focal) seizures
What are the side effects of Phenytoin?
Nystagmus, diplopia, ataxia, gingival hyperplasia, hirsutism, peripheral neuropathy, teratogenesis (fetal hydrantoin syndrome), megaloblastic anemia, SLE-like syndrome, induction of P-450, lymphadenopathy, Steven’s Johnson syndrome, osteopenia
When does sedation occur in Phenytoin use?
only @ HIGH levels of Phenytoin use!
What is Carbamazepine used for?
1st line treatment for simple and complex partial (focal) seizures & tonic-clonic seizures <– first line along with Phenytoin and Valproic acid
What is the mechanism of Carbamazepine?
Increases Na+ channel inactivation & decreases release of Glutamate
What else other than anti-seizure is Carbamazepine used for?
1st line for trigeminal neuralgia - brief episodes of sudden & severe unilateral “electric shock like” and “stabbing” pain (V2, V3)
Valproic Acid mechanism?
Increase Na+ channel inactivation; also increases GABA concentration by inhibiting GABA transaminase
What are the uses of Valproic acid? (5)
1st line for tonic-clonic seizures (1st line along with Phenytoin and Carbamazepine)
- Acutely for simple partial (focal) seizures
- Acutely for complex partial (focal) seizures
- Acutely for myoclonic seizures (along with Phenobarbital and Levetiracetam)
- Acutely for absence seizures
Side effects of Valproic acid?
GI distress, rare but fatal hepatotoxicity (must measure LFTs), neural tube deficits in fetus (spina bifida) so contraindicated in pregnancy, tremor, weight gain, hair loss
Other than anti-seizure, what is Valproic acid also used for?
Bipolar disorder as a mood stabilizer
Which anti-seizure drugs are highly bound to plasma protein?
Phenytoin & Valproic acid
What are the side effects of Carbamazepine?
- Diplopia
- Ataxia
- Blood dyscrasias (agranulocytosis, aplastic anemia so CBC should be monitored)
- Liver toxicity
- Teratogenesis
- Induction of cyt P-450 so may metabolize other drugs
- SIADH
- Stevens-Johnson syndrome
What is Stevens-Johnson syndrome?
Prodrome of malaise and fever followed by rapid onset of erythematous/purpuric macules in oral region, ocular region, and genitals)
Skin lesions progress to epidermal necrosis & sloughing
What is the mechanism of Gabapentin?
Gabapentin primarily inhibits high-voltage-activated Ca2+ channels; designed as GABA analog
What are the uses for Gabapentin? (3) *NOTE: HIGH doses needed
Used acutely for the following:
- Simple partial (focal) seizure
- Complex partial (focal) seizure
- Tonic-clonic seizure
What are the side effects of Gabapentin?
Sedation, ataxia
