Dental Anticonvulsants Flashcards
Traditional Antiepileptic Drugs
Phenobarbital (Luminal)
Phenytoin (Dilantin, Diphenylan)
Carbamazepine (Tegretol, Carbatrol)
Ethosuximide (Zarontin)
Valproic Acid (Depakote, Depakene)
Newer Antiepileptic Drugs
Gabapentin (Neurontin)
Pregabalin (Lyrica)
Oxcarbazepine (Trileptal)
Lamotrigine ( Lamictal)
Topiramate (Topomax)
Levetiracetam (Keppra)
Epileptic seizures
short term alteration in behavior due to disordered, synchronous, rhythmic firing of brain neurons
Partial (Focal)
Begin focally in a single site in cortex
Simple - preservation of consciousness, e.g. focal motor, jacksonian, somatosensory 20-60 sec
Complex - gradual loss of consciousness, may being w/ simple seizure, hallucination or strong emotions, may be followed by automatisms; lip smacking, hand wringing, 30 sec - 2 min
Generalized
involve both hemispheres of cortex from the beginning
Absence (petit mal) - (<30 sec) sudden impaired consciousness, staring, blinking, thalmic T-type Ca channels responsible for 3Hz spikes
Tonic-clonic (grand mal) - sudden impaired consciousness, 20 sec muscle rigidity then 1-2 min violent rhythmic body and limb movements
Secondarily generalized
starts with single focus area of the brain and then excites the hypothalamus and causes a generialized seizures
Anti-Epileptic Drug (AED) - MECHANISM OF ACTION
(Know this)
All drugs act to reduce neuronal activity, this also why some of these drugs are also used off label for controlling pain, bipolar disorder, etc.
Correct diagnosis of seizure type must occur prior to initiating drug therapy
Abscence seizures - ethosuximide and valproic acid - ONLY
Exacerbating abscence and myoclonic seizure - phenytoin, cabamazepine, gabapentin, tiagabine, oxcarbazepine, pregabalin and viagabatrin
Phenobarbital 1912 (Luminal)
monotherapy generialized tonic-clonic and partial seizures, IV formulation for status epilepticus
side effects - sedation in adults, irritability/hyperactivity in children (why pheno is no first line medication)
Phenobarbital 1938 (Dilantin, Diphenylan)
monotherapy generialized tonic-clonic and partial seizures; IV fosphenytoin for treatment of stat. epi.
side effects - GINGIVAL HYPERPLASIA AND STEVENS-JOHNSON SYNDROME
Steven-johnson syndrome (SJS)
<10% surface area, 5% mortality
adverse, immune system-mediated, drug reaction (not just anticonvulsants) characterized by blistering of skin and mucous
starts as a flu w/ presistent fever progressing to blisters then sloughing off of skin
treatment, discontinuation of use of suspected drug, immunosuppressives
toxic epidermal necrolysis (TEN) >30% SA, 20-40% mortality
Carbamazepine 1974 (tegretol, carbatrol)
monotherapy generialized tonic-clonic and partial seizures
side effects -
acute: stupor, coma, hyperirritability convulsions.
chronic: drowsiness, vertigo, ataxia, blurred vision. Induces CYP3A4 resulting in increased drug metabolism (e.g. oral contraceptives)
Oxcarbazepine 2000 (trileptal)
became generic oct 2007, structurally similar to carbamazepine
phamakokinectics - does not autoinduce like carbamazepine
side effects - increased drug metabolism (e.g. oral contraceptives)
Ethosuximide 1960 (Zarontin)
monotherapy abscence seizures
mechanism of action - inhibit T-type Ca channels
Valproic acid 1978 (Depakote, Depakene)
monotherapy abscence, myoclonic, partial and tonic/clonic seizures, IV formulation; broad spectrum AED
MOA - inhibit T-type Ca channels, prolong inactivation of Na channels, increase GABA synthesis (in vitro)