Anticonvulsants Flashcards
Hydantoin
Phenytoin (Dilantin)
Indication and MOA
Phenytoin (Dilantin)
- Used for tonic-clonic and partial complex seizures
- MOA: inhibit and stabilize electrical discharges in the motor cortex of the brain by affecting the influx of sodium ions during generation of nerve impulses
- Highly-protein bound
- CYP 450 med
- Least sedating seizure drug
Hydantoin
Phenytoin (Dilantin)
Cautions and Contraindications
- Avoid in sinus bradycardia, 2nd and 3rd degree AV heart block, Stocks-Adams syndrome (syncope with heart block)
- Caution in hypotension and myocardial insufficiency
- Caution in renal and hepatic impairment
- Rebound status epilepticus with sudden withdrawal
- Narrow therapeutic range (monitor blood levels)
- Avoid in pregnancy and lactation
- Approved in pediatrics
- Caution in elderly
- Avoid alcohol
Hydantoin
Phenytoin (Dilantin)
Adverse Drug Effects
- Agitation, ataxia, confusion, dizziness, drowsiness, headache, nystagmus, hypotension, tachycardia, n/v, anorexia, altered tase, gingival hyperplasia, discolored urine
- Hypersensitivity reactions (rare), SI (rare), blood dyscrasias (rare)
Carbamazepine (Tegretol)
Indication and MOA
- Used for focal and generalized onset seizures
- MOA: exact MOA unclear; thought to affect sodium channels, slowing influx of sodium in the cortical neurons and slowing the spread of abnormal activity
Carbamazepine (Tegretol)
Caution and Contraindications
- BBW: development of SJS and toxic epidermal necrolysis in Chinese patients
- BBW: blood dyscrasias (can transiently lower WBCs)
- BBW: dermatologic toxicity
- Caution in renal and hepatic impairment
- Can depress bone marrow and lead to pancytopenia and aplastic anemia (must get baseline CBC, CMP, TSH)
- Avoid in pregnancy and lactation
- Caution in elderly
- Approved in pediatrics
Carbamazepine (Tegretol)
Adverse Drug Effects
- drowsiness, dizziness, ataxia, n/v, skin rash, pruritus, constipation, tremors
- behavior changes (rare), SI (rare), multi-organ hypersensitivity (rare), hepatoxicity (rare)
- narrow therapeutic range; toxicity presents as HTN, tachycardia, stupor, agitation, respiratory depression, nystagmus, urinary retention, seizures, coma
Lamotrigine (Lamictal)
Indications and MOA
- Used for partial seizures, primary generalized tonic-clonic seizures
- MOA: thought to affect voltage sensitive sodium channels and inhibit presynaptic release of glutamate and aspartate in the neuron
- check for drug-drug interactions
Lamotrigine (Lamictal)
Caution and Contraindications
- BBW: serious skin reactions
- rebound status epilepticus with sudden withdrawal
- caution in renal and hepatic impairment
- avoid in pregnancy and lactation
- approved in children older than 2 years old
- oral contraceptives can decrease levels
Lamotrigine (Lamictal)
Adverse Drug Effects
- dizziness, headache, GI upset, diplopia, ataxia, insomnia, skin rash
- SI (rare), blood dyscrasias (rare), multi-organ hypersensitivity reactions (rare)
- immediately report any new onset of rash
Succinimides (Ethosuximide, Methosuximide)
Indications and MOA
- used for absence seizures
- MOA: decrease nerve impulses and transmission in the motor cortex
Succinimides (Ethosuximide, Methosuximide)
Caution and Contraindications
- do not take with alcohol
- can decrease effectiveness of birth control
- may continue in pregnancy with dose monitoring
- avoid in lactation
- rebound seizures can occur with withdrawal
- caution in renal and hepatic impairment
- approved for pediatrics older than 3 years old
Succinimides (Ethosuximide, Methosuximide)
Adverse Drug Effects
- GI distress, sedation, ataxia, lethargy, headache, rash, pruritus, mood changes
- SI (rare), blood dyscrasias (rare), dermatologic reactions (rare)
- narrow therapeutic range; toxicity can present as CNS depression, respiratory depression, acute nausea/vomiting
Valproic Acid (Depakote) Indications and MOA
- Used for focal (partial) onset seizures, generalized onset seizures, focal onset impaired awareness and absence seizures
- MOA: increases GABA availability, enhances the action of GABA, mimics its actions at postsynaptic sites; also blocks voltage-dependent sodium channels, which results in suppression of high-frequency, repetitive neuronal firing
Valproic Acid (Depakote) Caution and Contraindications
- BBW: hepatotoxicity
- BBW: severe pancreatitis
- avoid in pregnancy and lactation
- avoid in children younger than 2 years old
- caution in elderly patients; high risk of somnolence
- rebound seizures can occur with sudden withdrawal
Valproic Acid (Depakote) Adverse Drug Effects
- headache, drowsiness, dizziness, n/v, tremor, visual disturbance, weight gain, behavioral changes
- hypersensitivity reactions (rare), SI (rare), brain atrophy (rare)
- narrow therapeutic range; toxicity can present as CNS depression, confusion, jaundice