The ictal period is definied by rigid flexion of the extremities followed by extension.  This is often accompanied by a cry as the tensing of the body forces air out of the larynx.  This "tonic" phase lasts up to 30 seconds and is then followed by a "clonic" phase in which there are spasms. 
The post-ictal period involves drowsiness and confusion or a "post-ictal sleep".

Grand-Mal seizures, as they are a form of generalized seizure, involve a loss of consciousness and are often accompanied by incontinence.

Absence, Myoclonic, and Atonic seizures may worsen with phenytoin.  Do not prescribe phenytoin for these!

Memory trick: These are all of the non-convulsive generalized seizures!

do not use phenytoin for the non-convulsive generalized seizures

Phenytoin is used for both types of partial seizure: partial simple and partial complex.  It is also used for the more severe generalized seizures: Tonic-clonic and Status Epilepticus (diazepam and clonazepam are DOC for status epilepticus, though).

Recall that phenytoin is contraindicated in the non-convulsive generalized seizures (absence, atonic, myoclonic seizures) because it may actually worsen them!

Phenytoin can cause gingival hyperplasia, especially in children.

Seizures in pregnant women can lead to anoxic episodes in the fetus, which increase the risk of congenital birth defects.  Furthermore, pregnancy increases the frequency of seizures in most epileptic women!

However, most antiepileptic drugs are teratogenic!  Therefore, the risk-benefit ratio must be thoroughly considered.  Solution: give antiepileptic drugs at the absolute minimum dose required to control the seizures. 

(ex: phenytoin can result in cleft lip/palate, congenital heart defects, and mental deficiency.
Valproate causes NTDs ex: spina bifida)

Carbamazepine is the least teratogenic antiepileptic and pregnant women should be switched to this, at least through the first trimester

Phenytoin

Valproate

Carbamazepine

Phenobarbitol

Topiramate

The first 3 are the more important ones to remember (phenytoin, carbamazepine, valporoic acid)

These are the "big 3" as far as antiepileptic drugs are concerned, and they are used to treat "the biggie" of seizures (GRAND mal)

Liver function tests! carbamazepine is hepatotoxic.

It can also cause aplastic anemia, agranulocytosis, and thrombocytopenia!  yikes

you may also want to check their heart function because, as a tricyclic compound, carbamazepine is also cardiotoxic.

Myoclonic seizures are short episodes of muscle contraction that can occur at any age.  They are typically a result of neurological damage from hypoxia, uremia, drugs etc.

the treatment of choice is Valproate!

This is an absence seizure (petite mal) and it should be treated with ethosuxamide.

valproic acid is another effective drug against absence seizures but is not given to young children because of its hepatotoxicity

Theophylline (a methylxanthine drug used in asthma... it has a low therapeutic index!)
TCADs (amytryptaline, imipramine)

Phenothiazines (the older antipsychotics ex: chlorpromazine, trifluoperazine, prochlorperazine, fluphenazine)

theophylline was heavily emphasized in lecture

Generalized seizures begin in both hemispheres of the brain.  They are subdivided into convulsive and non-convulsive seizures.

Convulsive seizures = clonic and tonic-clonic (grand mal)

Non-Convulsive = absence (petit mal), myoclonic, and atonic seizures.

Valproic acid (valproate) and Ethosuximide are used to treat absence seizures (petit mal)

but recall, ethosuximide is the preferred drug in very young children

The benzodiazepines Diazepam and Clonazepam are the drugs of choice for treating status epilepticus.

B-C-D for status epilepticus
(use the Benzodiazepines: Clonazepam and Diazepam)

Lennox-Gestaut Syndrome is a form of seizure disorder that presents in children 2-6 years old.  The seizures (tonic or myoclonic) typically occur at night, and are difficult to treat. 

There are frequently accompanying behavioral problems or mental retardation.

Tx = Clonazepam or Lamotrigine

Carbamazepine is a CYP450 inducer!  This means it increases the metabolism of co-administered drugs, which can lead to their therapeutic failure.

For example: it increases the metabolism of COCPs, which can lead to pregnancy.  SO women of child bearing age should be counseled to use other forms of contraception if taking carbamazepine.

Valproic acid, a relatively well-tolerated anti-epileptic drug, causes weight gain, thinning of the hair, and liver damage.

Main points: valproic acid is
HEPATOTOXIC

and
CAUSES NEURAL TUBE DEFECTS

Recall that valproate is highly protein bound.  Salicylates, such as Aspirin, can displace valproate from plasma proteins, thereby increasing its toxicity....
Recall that valproate is hepatotoxic!

Carbamazepine is a CYP450 inducer and can increase the metabolism of oral contraceptives (COCPs) leading to their therapeutic failure and pregnancy.

Valproic acid is teratogenic and causes neural tube defects in the first trimester.  So if a young woman becomes pregnant while taking valproate, her fetus is at greater risk for conditions such as spina bifida.

Phenytoin blocks ion channels.  One ion channel it blocks is the sodum channel, making it an effective antiarrhythmic drug in addition to an antiepileptic.  We studied this under antiarrhythmics.  It is a class 1b antiarrhythmic.

 hinted at this being a mini exam question, or at least a popular board question

Phenytoin can also be used for cases of trigeminal neuralgia and neuropathic pain. (carbamazepine is also useful here)

Gingival Hyperplasia
Fetal Hydantoin Syndrome
Folic Acid Deficiency

Hirsuitism

*despite the fact that phenytoin causes folic acid deficiency, it is advised that folic acid not be given prophylactically to patients because it alters the metabolism of phenytoin.

Phenytoin, carbamazepine, and phenobarbitol induce the CYP450 system.

Phenytoin is of specific concern because inducing the metabolism of COCPs can lead to pregnancy, which would then place the fetus at risk for fetal hydantoin syndrome!

Use Ethosuximide. 

Both valproate and ethosuximide are good treatments for absence seizures, but because of valproate's hepatotoxicity, it is not used in young children.

Decrease the phenytoin dose because valproate will displace phenytoin from plasma protein. 

(Valproate is also a CYP450 inhibitor.  Both of these effects will increase the plasma levels of phenytoin, leading to toxicity)

Use ethosuximide to treat absence seizures in young children.

Ethosuximide works by blocking calcium channels in the thalamus.

Clonazepam and Diazepam are used to treat Status Epilepticus.

B-C-D for status epilepticus 
Benzodiazepines = Clonazepam and Diazepam

Gabapentin is a GABA analogue.  It is used as an alternative drug in partial seizures and tonic clonic seizures.  (Essentially a 2nd line drug anywhere carbamazepine or phenytoin are first line... so when you think of phenytoin or carbamazepine, think: "Good for simple & complex partial seizures or grand mal, and gabapentin would be a potential alternative")

It is also used as a mood stabilizer in patients with fast cycling bipolar disorder

Topiramate blocks release of glutamate.  It also increases GABA levels.

it is a secondary drug in partial seizures

Lamotrigine is an antiepileptic that blocks sodium channels and inhibits glutamate release.

It is used in both tonic clonic and partial seizures.

match the antiepileptic drug with whether it is a CYP450 inducer or inhibitor:

Valproate, Phenytoin, Carbamazepine, Phenobarbitol

Valproate= CYP450 inhibitor

Phenytoin, Carbamazepine, Phenobarbitol = CYP450 inducers!

Gabapentin

Valproate

Carbamazepine

all have mood stabilizer function.

You want your patients' moods to get very consitent on mood stabilizers

another awful mnemonic...

Valproate is effective in most types of epilepsy:

Tonic-clonic
Simple Partial
Complex Partial
Absence
Myoclonic
Atonic

However, recall that it is contraindicated in young children (hepatotoxicity) and in pregnant females (neural tube defects)

It also is a CYP450 inhibitor, thereby increasing the potency of co-administered drugs.

The antiepileptic Carbamazepine is the drug of choice for trigeminal neuralgia. 

Phenytoin or the TCAD amitriptyline can also be used.