E1- Anticonvulsants Flashcards
What type of seizure is characterized by:
- Focal, brief (20-90 sec)
- Grimacing, focal clonic jerking of an extremity
- No loss of consciousness
Partial simple seizure
What type of seizure is characterized by:
- Longer (<2 min)
- Automatic movements
- Altered or loss of consciousness; hallucinations
Partial complex seizure
What type of seizure is characterized by:
- Tonic-clonic with loss of consciousness
- Muscle contractions alternating with relaxation
Partial with secondary general
What type of seizure is characterized by:
- Sudden onset, brief
- Loss of awareness, but not consciousness
Absence (petit mal)
What type of seizure is characterized by:
- Initial tonic rigidity, subsequent tremor, eventual clonic jerking
- Loss of consciousness
Tonic-clonic (grand mal)
What type of seizure is characterized by:
-Brief spasm or rigidity
Myoclonic
What type of seizure is characterized by:
-Sudden loss of postural tone, pt can fall down
Atonic
What is the general MOA of anticonvulsants?
Increase GABA activity or decrease excitatory glutamate activity
Which anticonvulsants inhibit Na+ channels? (6)
Carbamazepine Phenytoin Topiramate Lamotrigine Valproate Zonisamide
Which anticonvulsants inhibit Ca2+ channels? (2)
What are their uses?
Ethosuximide
Valproate
Absence seizures
Which anticonvulsant inhibits both Na+ and Ca2+ channels?
Valproate
What are common SE of anticonvulsants? (4)
Teratogenicity
Suicide
Hypersensitivity (SJS)- screen for HLA-B allele, discontinue if develop rash
Failure of contraceptives
What should an OD of an anticonvulsant not be treated with?
CNS stimulants
Which anticonvulsant inhibits CYP450s?
Valproate
Which anticonvulsants induce CYP450s? (3)
Phenytoin
Carbamazepine
Phenobarbital
What is the difference between Phenytoin and Fosphenytoin?
Phenytoin (oral)
Fosphenytoin (injectable)
What is the MOA of Phenytoin and Fosphenytoin?
Prolongs inactivation of Na+ channels –> decreases glutamate activity
What are the uses of Phenytoin and Fosphenytoin? (2)
Partial seizures
Generalized tonic clonic seizures
What is the pharmacokinetics of Phenytoin and Fosphenytoin elimination?
Elimination is 1st order at low doses but zero order at therapeutic and higher doses
What are SE specific to Phenytoin and Fosphenytoin? (5)
Nystagmus Diplopia Ataxia Sedation Gingival hyperplasia
What is the MOA of Carbamazepine?
Blocks Na+ channels –> decreases glutamate activity
What is DOC for partial seizures?
Carbamazepine
What are uses of Carbamazepine? (4)
Partial seizures (DOC)
Generalized tonic-clonic seizures
Bipolar disorder
Trigeminal neuralgia
What are SE specific to Carbamazepine? (6)
Diplopia Ataxia GI upset Drowsiness Aplastic anemia Agranulocytosis
What is the MOA of Lamotrigine?
Inactivates Na+ channels –> decreases glutamate activity
Which anticonvulsant has the highest risk of SJS?
Carbamazepine
What are the uses of Lamotrigine? (2)
Partial seizures
Bipolar disorder
What are SE specific to Lamotrigine? (5)
Dizziness Diplopia Ataxia Somnolence N/V
What is the MOA of Topiramate?
Blocks Na+ channels –> decreases glutamate activity
What are the uses of Topiramate? (2)
Partial tonic-clonic seizures
Generalized tonic-clonic seizures
What are SE specific to Topiramate? (2)
Acute myopia
Glaucoma
What is the MOA of Levetiracetam?
Binds synaptic vesicular protein SV2A –> decreases glutamate activity and increases GABA release
What are uses of Levetiracetam? (3)
Partial seizures
Myoclonic seizures
Tonic-clonic seizures
What is the MOA of Phenobarbital?
Prolongs opening of Cl- channel at GABA receptor
What are the uses of Phenobarbital? (2)
Partial seizures
Generalized tonic-clonic seizures
What are possible drug interactions of Phenobarbital?
Induces CYP450s (increased metabolism of Phenytoin and Carbamazepine)
What is the MOA of Gabapentin?
GABA analog, may increase GABA release
What are the uses of Gabapentin? (3)
Adjunct for partial and generalized tonic-clonic seizures
Neuropathic pain
Bipolar disorder
What is the pharmacokinetics regarding Gabapentin elimination?
Elimination is 1st order; excreted unchanged by the kidney
What is useful about Gabapentin?
NO drug interactions
What is the MOA of Pregabalin?
GABA analog; binds to Ca2+ channels inhibiting excitatory neurotransmitter release
What are the uses of Pregabalin? (4)
Generalized anxiety disorder Neuropathic pain
Fibromyalgia
Post-op pain
What anticonvulsants have minimal drug interactions?
Levetiracetam
Gabapentin
Pregabalin
Tiagabine
What are SE specific to Pregabalin? (7)
Peripheral edema Dizziness Weight gain Xerostomia Ataxia Blurred vision GI upset
What is the MOA of Tiagabine?
Inhibits reuptake of GABA enhances GABA activity
What is the use of Tiagabine?
Adjunct for partial seizures
What is the MOA of Vigabatrin?
Irreversibly inhibits GABA transaminase
What are the uses of Vigabatrin? (2)
Refractory complex partial seizures Infantile spasm (West’s syndrome)
What are SE specific to Vigabatrin? (2)
Visual field problems
Retinal damage
What is the MOA of Ethosuximide?
Inhibits low-threshold (T-type) Ca2+ channels
What is DOC for absence seizures?
Ethosuximide
What SE is specific to Ethosuximide?
Hiccup
What is the MOA of Valproic acid?
Blocks Ca2+ channels AND Na+ channels
What are the uses of Valproic acid? (3)
Absence and general tonic-clonic seizures (“mixed” seizures”)
Bipolar disorder
Migraine prophylaxis
What are SE specific to Valproic acid?
Hepatoxicity
Teratogenic- increase risk of spina bifida
What is the MOA of Clonazepam (BZ)?
Stimulates GABA receptor and enhances GABA inhibition
What are the uses of Clonazepam (BZ)? (3)
Absence seizures
Myoclonic seizures
Infantile spasms (West’s syndrome)
What is the MOA of Diazepam (BZ) and Lorazepam (BZ)?
Stimulates GABA channel
What is the DOC for Status Epilepticus?
Diazepam (BZ) and Lorazepam (BZ)
