Term
|
Definition
| an uncontrolled paroxysmal electrical activity in the brain which results in motor, sensory, or behavioral dysfunction. |
|
|
Term
| what are the etiologies for seizure? |
|
Definition
| primary (idiopathic) and secondary (symptomatic: CNS trauma, neoplasm/glial scarring, anoxia, infections, *drug withdrawal [alcohol]*, and abnormalities [cerebral palsy]) |
|
|
Term
| what are tie different types of seizure? |
|
Definition
| partial (*simple, *complex, and *partial seizures secondarily generalized [partial which moves to generalized]) and generalized (*absence [petit mal: pt goes blank], *atypical absence, *myoclonic [muscle], *clonic, *tonic [rigid], *tonic-clonic [grand mal: rigid+back and forth], and *atonic [complete loss of tone]) |
|
|
Term
| what are the animal models for seizure testing? what types of seizure do they correlate to? |
|
Definition
| electro-convulsive shock (ECS - reproduces tonic, clonic, and partial seizures), pentylenetrazol (PTZ - reproduces absence seizures), kindling, and genetic mutations |
|
|
Term
| what kinds of activity can lead to seizure production? |
|
Definition
| increased excitatory OR decreased inhibitory activity |
|
|
Term
| changes in what may lead to seizure? |
|
Definition
| plasma electrolytes, pH, pCO2, emotional stress, and visual stimuli |
|
|
Term
| what characterizes the spread of seizure activity? |
|
Definition
| kindling mechanism (low frequency stimulus to amygdala over a period of time), reduced inhibition, and **accumulation of extracellular K+ (most predominant - due to hyperexcitable neuron releasing K+ which causes other neurons [including upper motor neurons] to also fire) |
|
|
Term
| what is the protective effect produced by anticonvulsants? |
|
Definition
| anticonvulsants prevent spread of abnormal electrical stimuli by stabilizing neurons surrounding the focus |
|
|
Term
| what are the mechanisms of action associated w/anticonvulsants? |
|
Definition
| block of Ca++, K+, Na+ activities and facilitation of GABA activity (increase: duration of channel opening, frequency of channel opening, synaptic concentration of GABA) |
|
|
Term
| what are the hydantoin anticonvulsants? MOA? |
|
Definition
| phenytoin, mephenytoin, and ethotoin. these limit the development of seizure activity in the focus, limit the spread from the focus and **inhibit voltage-gated Na+ channels**. |
|
|
Term
| what is phenytoin the DOC for? |
|
Definition
| most seizures, **except absence seizures |
|
|
Term
| what ADRs are associated w/hydantoin? |
|
Definition
| toxicity: nystagmus, diplopia, vertigo, and ataxia. side effects: hirsutism, gingival hyperplasia, and hepatic microsomal enzyme induction (increases CYP metabolism of other drugs). |
|
|
Term
| what are the barbiturate anticonvulsants? MOA? |
|
Definition
| phenobarbital, metharbital, mephobarbital, and primidone (not actually a barbiturate, but it’s metabolized to phenobarbital – have barbiturate activity). MOA: limit spread of seizure activity and elevates seizure threshold, and GABA enhancement. |
|
|
Term
| when are barbiturate anticonvulsants generally used? |
|
Definition
| for generalized or partial seizures |
|
|
Term
| what is the effect of barbiturate toxicity? |
|
Definition
| tolerance to sedation, exfoliate dermatitis, megaloblastic anemia, and hepatic microsomal enzyme induction (barbiturates induce the P450 system - will metabolize other drugs faster) |
|
|
Term
| what are the succinimide anticonvulsants? MOA? |
|
Definition
| ethosuximide, methsuximide, and phensuximide. MOA: unknown (not via GABA or Na+ channels) |
|
|
Term
| what are the succinimide anticonvulsants used for? |
|
Definition
| *absence seizure - of which ethosuximide is the DOC for. also may be useful for tonic-clonic seizures if phenytoin isn't working. |
|
|
Term
| what is the effect of succinimide toxicity? |
|
Definition
| n/v, diarrhea, sedation, drowsiness, *inhibition of platelet aggregation, hepatotoxicity, and possible *teratogenic effects |
|
|
Term
| what is the MOA associated w/carbamazepine? |
|
Definition
| carbamazepine prolongs the refractory period (reduces firing rate), decreases the spread of activity from the focus, and decreases the excitation of neurons by decreasing Na+ and K+ conductances. |
|
|
Term
| what are the uses associated w/carbamazepine? |
|
Definition
| partial, psychomotor and generalized tonic-clonic. *not for absence* |
|
|
Term
| what ADRs are associated w/carbamazepine? |
|
Definition
| blurred, vision, drowsiness, dizziness, ataxia, nausea - to all of which tolerance can develop. also, renal/hepatic function and hematological parameters should be monitored due to rare by severe side effects. |
|
|
Term
| what MOA is associated w/valproic acid? |
|
Definition
| valproic acid prevents PTZ-induced seizures, blocks ECS seizures, prevents kindled seizures, decreases voltage sensitive Na+ channels, and enhances GABA accumulation |
|
|
Term
| what is valproic acid used for? |
|
Definition
| absence, generalized, partial, myoclonic and atonic seizures |
|
|
Term
| what toxicities are associated w/valproic acid? |
|
Definition
| anorexia, n/v, idiosyncratic hepatotoxicity, and high doses may inhibit platelet function. |
|
|
Term
| what is trimethadione used for? |
|
Definition
| protection from absence/PTZ induced seizures via unknown MOA. |
|
|
Term
| what ADRs are associated w/trimethadione? |
|
Definition
| hemeralopia, hepatitis, nephrosis, and bone marrow damage |
|
|
Term
| what are the benzodiazepine anticonvulsants? MOA? |
|
Definition
| clonazepam, clorazepate, lorazepam, and diazepam. MOA: limiting spread of activity from focus and enhancement of GABA. |
|
|
Term
| what kinds of seizure are benzodiazepines used for? |
|
Definition
| absence, myoclonic, and atonic seizures as well as status epilepticus (long duration, non-controlled seizure - leads to systemic hypoxia, acidemia, hyperpyrexia, cardiovascular collapse, and renal shut down) |
|
|
Term
| what toxicities are associated w/benzodiazipines? |
|
Definition
| drowsiness, ataxia, and personality changes (aggression, hyperactivity, irritability - mainly in children) |
|
|
Term
| what is the MOA associated w/acetazolamide? what is it used for? |
|
Definition
| this carbonic anhydrase inhibitor diminishes absence seizures via production of systemic acidosis - but its usefulness can be limited by tolerance. |
|
|
Term
| what toxicity is associated w/acetazolamide? |
|
Definition
| drowsiness and paresthesia |
|
|
Term
| what characterizes use of phenacemide? |
|
Definition
| phenacemide is used as adjunctive therapy in complex partial seizures which are refractory to other agents |
|
|
Term
| what characterizes phenacemide toxicity? |
|
Definition
| hepatitis, nephritis, aplastic anemia (periodic assessment of hepatic/renal/bone marrow function = mandatory), and psychologic effects (depression - psychotic). |
|
|
Term
|
Definition
| felbamate may be used for partial seizures (in conjunction w/phenytoin or carbamazepine) and its MOA is unknown. |
|
|
Term
| what characterizes felbamate toxicity? |
|
Definition
| felbamate is limited to the most severe/refractory pts b/c it has been linked to 2 deaths from 10 reported cases of aplastic anemia and 4 deaths among 8 cases of acute liver failure. this drug cannot be used by patient until there has been a complete discussion of the risks and the patient, parent or guardian has provided written informed consent. |
|
|
Term
| which anticonvulsant drugs have the effect of enzyme induction? |
|
Definition
| carbamazepine, felbamate, phenobarbital, phenytoin, primidone |
|
|
Term
| what ADRs are common to most anticonvulsant drugs? |
|
Definition
| sedation, GI disturbances, skin eruptions (hypersensitivity), and blood dyscrasias |
|
|
Term
| what drugs are associated w/paradoxical excitement? |
|
Definition
| BDZs (benzodiazepines), phenobarbital |
|
|
Term
| what drugs are associated w/ataxia? |
|
Definition
| phenytoin, BDZz, phenobarbital |
|
|
Term
| what drugs are associated w/visual disturbances? |
|
Definition
| carbamazepine, phenytoin, clonazepam |
|
|
Term
| what drugs are associated w/gingival hyperplasia? |
|
Definition
|
|
Term
| what drugs are associated w/megalobastic anemia? |
|
Definition
| phenytoin, primidone, phenobarbital |
|
|
Term
| what drugs are associated w/hepatitis? |
|
Definition
| phenytoin, valproic acid, carbamazepine |
|
|
Term
| what drugs are associated w/hirsutism and hypertrichosis? |
|
Definition
|
|
Term
| what drugs are associated w/inhibition of platelet aggregation and alopecia? |
|
Definition
|
|
Term
| what drugs are used for generalized tonic-clonic seizures and partial seizures (motor and sensory)? |
|
Definition
| phenytoin (DOC), phenobarbital, primidone, carbamazepine |
|
|
Term
| what drugs are used for partial seizures w/complex symptoms (psychomotor)? |
|
Definition
| phenytoin, carbamazepine, and valproic acid |
|
|
Term
| what drugs are used for partial seizures w/complex symptoms (psychomotor)? |
|
Definition
| phenytoin, carbamazepine, and valproic acid |
|
|
Term
| what drugs are used for absence seizures? |
|
Definition
| ethosuximide, clonazepam, and valproic acid |
|
|
Term
| what drugs are used for myoclonic seizures? |
|
Definition
| valproic acid and clonazepam |
|
|
Term
| what drugs are used for atonic and akinetic seizures? |
|
Definition
| clonazepam and valproic acid |
|
|
Term
| what drugs are used for status epilepticus? |
|
Definition
| diazepam/lorazepam or phenytoin |
|
|
