Anticonvulsants Flashcards
the goal of anticonvulsants:
is to suppress the rapid and excessive firing of neurons that start a seizure. Failing this, a good anticonvulsant would prevent the spread of the seizure within the brain and offer protection against possible excitotoxic effects that may result in brain damage.
Seizures
A seizure is a sudden change in behavior due to abnormal synchronization and excessive electrical activity in the brain.
• During a seizure, neurons may fire as many as 500 times a second, much faster than the normal neuronal firing rate of 80 times a sec.
There are a wide variety of possible seizure presentations depending in large part on which areas of the brain are affected. The site in the brain of the abnormal electrical activity often determines the seizure symptoms that are produced.
status epilepticus
a continuous seizure that will not stop without intervention.
Seizure triggers
- Certain environmental factors can lead to an increased likelihood of seizures in someone with epilepsy such as:
- Flashing lights
- Sleep deprivation
- Alcohol consumption
- Stress or anxiety
- Illness
hypnogogic seizures
Seizures that occur during sleep or at the transition between sleep and wakefulness
Non-epileptic seizure causes
- There are dozens of potential causes for non-epileptic seizures such as:
- Space occupying brain lesions
- Head trauma
- Drug side effects, toxicity, withdrawal
- Fever
- Meningitis, encephalitis
- Metabolic/ electrolyte abnormalities
simple vs complex seizures
simple seizures (no change in level of consciousness) or complex seizures (change in level of consciousness occurs).
partial /focal vs generalized seizures
partial or focal seizure when only one part or side of the body is affected or a generalized seizure when the entire body is affected.
Partial seizures
ccur in just one part of the brain.
• Approximately 60 percent of people with epilepsy have focal seizures.
• These seizures are frequently described by the area of the brain in which they originate. For example, someone might be diagnosed with focal frontal lobe seizures or a focal temporal lobe seizure.
Simple partial seizures
In a simple partial seizure, the person will remain conscious but experience unusual feelings or sensations that can take many forms.
• The patient may experience sudden and unexplainable feelings of fear, joy, anger, or sadness out of context with stimuli.
• He or she may also experience hallucinations that involve sight, sound, smell, taste, or skin sensation.
Complex partial seizures
• In a complex partial seizure, the person
has a change in or loss of consciousness.
• People having a complex partial seizure may display strange, repetitious behaviors such as blinks, twitches, and mouth movements, or motions such as walking in a circle.
• These repetitious movements are called automatisms and these seizures usually last just a few seconds.
Absence seizures
• Absence seizures involve an interruption in consciousness where the person experiencing the seizure seems to become vacant and unresponsive for a short period of time (usually up to 30 seconds).
• Slight muscle twitching may also occur.
• These seizures are sometimes referred to as petit mal seizures.

Generalized seizures / tonic clonic or grand mal
• Tonic-clonic seizures cause a mixture of symptoms, including stiffening of the body and repeated jerks of the arms and/or legs as well as loss of consciousness.
• Tonic-clonic seizures are sometimes referred to by the term, grand mal seizures.

initial contraction of the muscles (tonic phase) which may involve tongue biting, urinary incontinence and the absence of breathing. This is followed by rhythmic muscle contractions (clonic phase).
Status epilepticus
• Status epilepticus refers to continuous seizure activity with no recovery between successive seizures.
• A tonic-clonic seizure lasting longer than 5 minutes (or two minutes longer than a given person’s usual seizures) should be considered a medical emergency.

Anticonvulsant drugs
- The main mechanism of action of drugs in this class is as follows:
- Sodium channel blockade
- Calcium channel (T-type) blockade
- Potentiate GABA - inhibitory neurotransmission -
- Decrease Glutamate - excitatory neurotransmission
Nearly all AEDs function by decreasing the excitation of neurons (i.e. by blocking fast or slow sodium channels or modulating calcium channels or by enhancing the inhibition of neurons (i.e. by potentiating the effects of inhibitory neurotransmitters like GABA).
Partial seizures drugs
- Phenytoin/ Dilantin
- Phenobarbital/Phenobarb
- Primidone/ Mysoline
Absence seizures (Petit mal) drugs
- Ethosuximide/ Zarontin
- Valproic acid/ Depakote
- Clonazepam/ Klonapin
Generalized tonic clonic seizures (Grand mal seizures) drugs
- Diazepam/ Valium
- Phenytoin/ Dilantin
- Carbamazepine/ Tegretol
- Phenobarbital/ Phenobarb
- Primidone/ Mysoline
- Lamotrigine/ Lamactil
- Levetriacetam/ Keppra
- Topiramate/ Topamax (also used to treat bipolar disorder or to counteract the weight gain associated with numerous antidepressant)