CNS: ANTI-SEIZURE DRUGS Flashcards
Epileptic seizures
- seizures are episodes of abnormal electrical activity in the brain causing _______ movement, ______ or ______
- seizures may be caused by head trauma, stroke, fever, alcohol and drug withdrawal etc
- ________ seizures without any proximal cause are seen in patients with epilepsy
- seizures are accompanied by _______ changes in the EEG
- there are two categories of seizures
1) Partial (focal) seizures (_______/______)
2) Generalized seizures (______/______)
involuntary sensations thoughts recurrent characteristic Jacksonian, simple tonic-clonic, absence
Antiseizure drugs
MOA: suppress the formation and spread of abormal _____ activity or charges via:
1) inhibition of _____ or ______ influx
-inhibit activity of voltage dependent __ channels
-inhibit activity of voltage dependent __ channels
2) augment _____ (inhibitory). neurotransmission
3) inhibit ______ (excitatory) neurotransmssion
electric Na+, Ca+ Na+, Ca+ GABA Glutamate
antiseizure drugs
MOA
1) Enhancement of GABA actions
-increase GABA actions at receptor (_________)
-_______
-_______
2) Inhibition of ______ channels: prolongs the time that the sodium channels inactivation gate remains _______
-________, ______, ______, ______
3) Inhibition of ______ channels (_______)
benzodiazepines vigabatrin tigabin sodium phenytoin, carbamazepine, valproic acid, lamotrigine calcium ehtosuximide
anti seizure: GABA-ergic Mechanism of Action: Augment effects on GABA -Facilitate GABA neurotransmission by: -increased GABA release: \_\_\_\_\_\_\_ -blocking GABA uptake uptake: \_\_\_\_\_\_\_ -enhance the action of GABAa receptor: \_\_\_\_\_\_\_, \_\_\_\_\_\_\_ -inhibit. GABA transminase: \_\_\_\_\_\_\_\_ -inhibit GABA degradation: \_\_\_\_\_\_\_\_\_\_\_
gabapentin tiagabin topiramate, benzodiazepenes vigabatrin valproate
Antiepileptic Drugs: NMDA
MOA
-effects on _______ via _____ channels
-at the post synaptic membrane, ______ activates NMDA. receptors, resulting in _____ influx
–calcium contributes to long term potentiation of excitatory glutamate neurotransmission
-_______, ______, and _________ inhibit glutamate neurotransmission by blocking ___, __, and ___ influx
glutamate calcium glutamate calcium felbamate, topiramate, valproate Zn+, K+, and Ca++ influx
Phenytoin (Dilantin) inhibition of \_\_\_\_\_ channels: -A Hydantoin derivative -blocks voltage sensitive \_\_\_\_\_ channels -decreases \_\_\_\_\_\_ transmission -poorly \_\_\_\_, several formualtions with different bioavailability --require \_\_\_\_\_\_\_\_\_ --\_\_\_\_\_\_\_\_ (cerebyx) - new formulation more soluble, prevents precipitation after IM injections
sodium sodium synaptic soluble therapeutic monitoring fosphenytoin
Phenytoin (Dilantin) Adverse Effects
- ___________
- ______ metabolism - birth defects
- -syndrome: malformation of ears, lips, palate, mouth spine
- -imperforate ____, mental ______
CNS effects
–ataxia, diplopia, nystagmus, slurred speech, confusion
_______, blood ________
- Vitamin __ metabolism
- -decreased ______ absorption froom GIA, may lead to osteomalacia
gingival hyperplasia folate anus retardation hirsuitism, blood dyscrasias D
Carbamazepine Indications -partial siezures -generalized tonic clonic siezures -\_\_\_\_\_\_\_ neuralgias (Drug of choice) -\_\_\_\_\_\_ -fibromyalgia -bipolar disorder -chronci pain as analgesic adjuvant
trigeminal
sciatica
Valproate Several. formulations -\_\_\_\_\_\_\_\_\_\_\_\_ (Depacon) -\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_(Depakene) MOA 1) Inhibits voltage sensitive \_\_\_\_\_\_. and \_\_\_\_\_\_ channels 2) Increases \_\_\_\_ synthesis -absorbed more slowly, less GI adverse effects
Adverse Effects
- _______, drowsiness
- behavioral and mood changes
- _________ effects
- -diplopia; nystagmus
- _______
- ______ toxicity (monitoring suggested)
- increase _______ and other _______
valproate sodium valproic acid sodium, calcium GABA sedation opthalmological weight gain hepatic spina bifida birth defects
Valproate Drug Interactions
- inhibits _______ of other drugs
- -increase blood levels of ________ and_______ (Lamictal)
- -decrease blood levels of _________
- ____ depressants
- ________ drugs
metabolism barbiturates, lamotrigine carbamazepine CNS hepatotoxic
Newer Antiepileptics
Gabapentin (Neurontin)
-GABA analogue
-increased release of ___ from central neurons by interacting with _______ channels
-may alter ____ metabolism
-____ half life dosing: several times a day
-use in combination with other agents for all forms of partial seizures
-Adverse effects
-_______: crying, false sense of well being, hostility
-amnesia, depression, irritability
GABA calcium GABA short behavioral
Newer Antiepileptics Lamotrigine (Lamictal) -blocks voltage sensitive \_\_\_\_\_ channels -decreases presynaptic release of excitatory neurotransmitters (\_\_\_\_\_\_) adverse effects -\_\_\_\_\_\_\_\_ dysfunction; \_\_\_\_\_\_\_\_ -rash: may progress to \_\_\_\_\_\_\_\_\_\_ syndrome decreases effects of other \_\_\_\_\_\_ agents
sodium glutamate cerebellar, drowsiness Stevens-Johnson syndrome antiepileptic
Newer Antiepileptics Topiramate (Topamax) -blocks voltage sensitive \_\_\_\_\_\_\_ channels -activation of \_\_\_ receptors -blocks two type \_\_\_\_\_\_ receptor -\_\_\_ and \_\_\_
sodium
GABA
glutamate
kinate, AMPA
Newer Antiepileptics \_\_\_\_\_\_\_ -blocks \_\_\_\_\_ uptake by presynaptic neurons and glial cells -increases \_\_\_\_ concentrations -inhibits \_\_\_ seizure firing
-_________ - blocks _____ activation of ______ receptors and inhibits initiation of seizures
Tiagabine GABA GABA low Felbamate Glycine NMDA
Antiepileptic Pharmacotherapy
_________ is preferable to polytherapy
-the antiepileptic agent is selected based on type of siezure and the epileptic syndrome
–_________ and _______ are drugs of choice for complex partial seizures
–_________, ________, and ______ are equally effective for treatment of secondary generalized tonic clonic seizures
-________ is not recommended with other anti-siezure drugs
-newer anti-epileptics when convential fail
monotherapy
carbazepine, phenytoin
carbamazepine, phenytoin, valproate
lamotrigine
