Anti-epileptic drugs Flashcards
Brief recurrent myoclonic jerks of body with sudden flexion or extension of the body and limbs that presents before 1 yo
Infantile spasms/West syndrome
Severe myoclonic epilepsy in infancy
Dravet syndrome
More than 5 minutes of generalized convulsive seizure, or 2+ seizure episodes without recovery of consciousness in between
Status epilepticus
Drugs for epilepsy that act on Na channels
Phenytoin
Carbamazepine
Lamotrigine
Topiramate
Valproic acid
Drugs for epilepsy that act on Ca channels
Ethosuximide
Valproic acid
Strategies of epilepsy treatment
-stabilize membrane by blocking voltage-gated channels to prevent depolarization
-Increase GABA-ergic transmission
-Decrease excitatory glutamate transmission
Mechanism of phenobarbitone
Potentiation of synaptic inhibition through action on GABA-A receptors by prolonging opening of Cl channels
Toxicity of phenobarbitone
Sedation
Nystagmus and ataxia
Rashes
Megaloblastic anemia
Osteomalacia
Drugs for generalized tonic clonic seizures
Phenobarbitone
Phenytoin
Carbamazepine **
Valproic acid
Zonisamide
Topiramate
Parampanel (adjuvant)
Drugs for simple partial/focal aware seizures
Phenobarbitone
Phenytoin
Lacosamide
Carbamazepine **
Valproic acid
Tiagabine (adjuvant)
Vigabatrin (adjuvant)
Zonisamide
Levetiracetam
Topiramate
Parempanel (adjuvant)
Drugs for complex partial/focal impaired awareness
Phenobarbitone
Phenytoin
Lacosamide
Carbamazepine
Valproic acid
Lamotrigine (adjuvant)
Levetiracetam
Drugs for status epilepticus
Phenobarbitone (IM or IV)
Phenytoin
Prodrug of phenobarbital
Primidone
Mechanism of phenytoin/dilantin
Limits the sustained high frequency repetitive firing of APs
Slows the rate of recovery of voltage activated NA channels
Pharmacokinetics of phenytoin
Highly protein bound
Microsomal enzyme inducer
Metabolism shifts from first order to zero order kinetics (saturation kinetics)
Adverse effects of phenytoin
Gum hypertrophy
Hirsutism
Coarse facial features
Acne
Drug induced lupus
Megaloblastic anemia
Osteomalacia
Epilepsy drug that can cause fetal hydantoin syndrome if taken in pregnancy
Phenytoin
Therapeutic range of phenytoin
10-20 mcg/mL
Additional use of phenytoin, other than epilepsy
Trigeminal neuralgia
IV form of phenytoin
Fosphenytoin
Mechanism of lacosamide
Na channel blocking antiseizure drug
Mechanism of carbamazepine
Inhibits high frequency repetitive firing by prolonging the inactivated state of Na channels
Adverse effects of carbamazepine
Drowsiness
Vertigo
Ataxia
Diplopia
Blurred vision
Hyponatremia and water intoxication
Idiosyncratic reactions –> agranulocytosis and aplastic anemia
Most effect drug for complex partial/focal impaired awareness
Carbamazepine
First choice drug for general tonic-clonic and simple partial/focal aware seizures
Carbamazepine
Other, non epileptic, uses for carbamazepine
Neuralgias
Bipolar disorder
Acute mania
Drug interactions of carbamazepine
Induces microsomal enzymes
Metabolism inhibited by macrolide antibiotics
Less potent analog of carbamazepine
Oxcarbazepine
Mechanism of ethosuximide
Primarily on thalamocortical system that selectively inhibits low threshold, high amplitude, T type Ca current
Toxicity of ethosuximide
Gastric distress
Lethargy and fatigue
Hypersensitivity
Drug induced lupus
Drugs used for absence seizures
Ethosuximide
Valproic acid
Clonazepam
Mechanism of valproic acid
Inhibits sustained repetitive firing, reduces low threshold T type Ca current, and increases levels of GABA
Toxicity of valproic acid
Transient GI symptoms
Alopecia
Curling of hair
Rashes
Stimulation of appetite
Fulminant hepatitis
Hyperammonemia
Effect of using valproic acid in pregnancy
NTDs
Drugs used in myoclonic and atonic seizures
Valproic acid
Other, non-epileptic, uses of valproic acid
Bipolar disorder
Mania
Mechanism of felbamate
Block NMDA receptor
Side effects of felbamate
Aplastic anemia
Severe hepatitis at unexpectedly high rates
Third-line drug for refractory partial seizures
Felbamate
Drugs for Lennox-Gestaut syndrome
Valproic acid
Felbamate
Clobazam
Medications used for emergency control of convulsions in status epilepticus, tetanus, or eclampsia
Diazepam
Lorazepam
Add on drugs for partial and general tonic-clonic seizures
Gabapentin
Pregabalin
Mechanism of gabapentinoids
Bind to alpha-2-delta, decreasing glutamate
Mechanism for tiagabine
Inhibitor of GABA uptake
Drug of choice for infantile spasms
Vigabatrin
Mechanism of lamotrigine
Blocks Na channels
Prevents release of excitatory NTs
Toxicity of lamotrigine
Rash
Stevens-Johnson syndrome
Mechanism of levetiracetam
Binds selective to SV2A, reducing the release of the excitatory NT glutamate
Pharmacokinetics of levetiracetam
Not metabolized by cytochrome P450
No interactions with other antiepileptics
Mechanism of topiramate
Block Na channels
Potentiates actions of GABA
May also block glutamate receptors
Side effects of topiramate
Kidney stones
Mechanism of parempanel
Selective non-competitive antagonist of AMPA receptors
Only approved uses of cannabidiol
Dravet syndrome
Lennox-Gestaut syndrome
Drug interactions of carbamazepine
Phenytoin
Valproate
Macrolide antibiotics
Phenobarbital
Side effect of lacosamide
Small increase in PR interval
Drug interactions of phenytoin
Phenobarbital
Carbamazepine
OCPs
Valproate
Interactions of phenobarbital
Valproate
Carbamazepine
Phenytoin
Steroids