Pharmacology - Anticonvulsants (Exam 2) Flashcards
Brief, temporary disturbance in electrical activity of the brain; a single episode of jerky movements
Seizure (convulsion)
Recurring seizures; group of disorders characterized by abnormal electrical discharge from CNS neurons in the form of imbalance between excitatory and inhibitory impulses
Epilepsy
Excitatory receptors
NMDA
AMPA
Excitatory neurotransmitters
Glutamate
Aspartate
Inhibitory receptor
GABA-R
Inhibitory neurotransmitter
GABA
Benzodiazepines cause increased _______, leading to ______ __________ and ________
inhibition; CNS depression and sedation
If you have too much __________ signals or too little ________ signals, you can have __________
excitatory; inhibitory; epilepsy
Petit mal
Absence seizures
Seizures that cause you to lose focus, blink rapidly, or stare out into space for a few seconds
Absence seizures
Grand mal
Tonic-clonic seizures
Seizures that cause you to cry out, fall to the ground, or experience strong muscle jerking or contractions
Tonic-clonic seizures
What are the 2 generalized seizures?
- Absence seizures
- Tonic-clonic seizures
What are the 3 focal (partial) seizures?
- Simple
- Complex
- Secondary generalized
Seizures that affect a small part of the brain and can have minimal symptoms like a small twitch or strange taste in your mouth
Simple focal seizure
Seizures that involve multiple areas of the brain and cause confusion; disoriented or unable to respond for a few seconds to minutes
Complex focal seizure
Seizures that begin as focal seizure in one part of the brain and progress to a generalized seizure
Secondary generalized seizure
Seizures that are very prolonged and cause brain damage or death; EMS must be called
Status epilepticus
How do anti-seizure drugs work?
Reduce excitatory signals
Enhance inhibitory signals
How do you reduce excitatory signals?
Inhibit glutamate/aspartate release
Inhibit NMDA/AMPA signaling
How do you enhance inhibitory signals?
Block GABA reuptake
Enhance GABA-R signaling
How to block action potential
- Enhance Cl- channels
- Block Na+ channel
- Enhance K+ channel
What drug is a barbiturate? What is it used to treat?
Phenobarbital; treats seizures
How does phenobarbital work?
Enhance binding of GABA
Increase the time that GABA-A activated Cl- channels are open
What is an adverse effect of barbiturates?
Osteomalacia
What drugs are hydantoins?
Phenytoin
Dilantin
How do phenytoin, dilantin, and carbamazepine work?
Reversible binding to inactivated Na+ channels
Stabilize Na+ channels in inactivated state
What factors can alter phenytoin protein binding? What do all of these factors cause?
Hypoalbuminemia
Renal disease
Presence of displacing drugs (ex: aspirin)
Causes increased unbound (“free”) drug
What are the adverse effects of hydantoins?
Fetal hydantoin syndrome (cleft lip, cleft palate, congenital heart disease, neural tube defect)
Osteomalacia (interferes with Ca2+ absorption)
Which drug causes gingival overgrowth?
Phenytoin
What drug is the 1st choice for absence seizures?
Ethosuximide
What is the mechanism for ethosuximide?
Reduce Ca2+ influx through T type Ca2+ channels
What is the mechanism for valproic acid?
Binds to inactivated Na+ channels
Reduces Ca2+ influx through T type Ca2+ channels
Enhances GABA activity
What can valproic acid cause?
Spina bifida and neural tube defects
What are the 3 things GABA drugs do?
- Increase GABA-R activation
- Inhibit GABA transaminase
- Inhibit GABA transporter-1
What drugs are benzodiazepines?
Diazepam
Midazolam
What is the mechanism for diazepam and midazolam? What do they treat in emergencies?
Increase GABA-R activation
Treat status epilepticus
What drug is a neurosteroid?
Ganaxolone
What is the mechanism for ganaxolone?
Steroid binding site (allosteric site) on GABA-R
What is the mechanism of vigabatrin?
Inhibits GABA transaminase
(vigabaTRin - TRansaminase)
What is the mechanism for tiagabine?
Inhibits GABA transporter-1
(Tiagabine - Transporter)
What is the mechanism for gabapentin?
Inhibits L-type Ca2+ channels
What is the mechanism for lamotrigine?
Binds to inactivated Na+ channels
What is the mechanism for levetiracetam?
Synaptic vesicle glycoprotein inhibition - modulates glutamate release
Which drugs are the GABA acting drugs (gabanoids)?
Vigabatrine
Tigabine
Ganaxolone
Gabapentin
What is the main aim for anti-epileptic drugs?
Control seizures with least # of drugs
T/F you should never stop treatment with anti-epileptic drugs suddenly
True, stopping suddenly could cause status epilepticus
What should you do if a patient has a seizure in your office?
Inject midazolam intra buccal, IV, IM
Repeated or continuous seizures for > 5 minutes or no return to baseline
Status epilepticus (emergency!)
Which drugs can treat status epilepticus?
Benzodiazepines:
Diazepam
Midazolam
