Pharm week 7 anti-convulsants Flashcards
partial seizures
Have onset in one
particular part of the brain,
resulting in focal symptoms
such as twitching in an
arm or face, a sensory
change, or even the focal
type of change in memory
that occurs with temporal
lobe seizures.
simple partial seizures
These can be motor seizures with twitching,
abnormal sensations, abnormal visions, sounds
or smells, and distortions of perception. Seizure
activity can spread to the autonomic nervous
system, resulting in flushing, tingling, or
nausea. All such simple partial seizures will be in
clear consciousness and with full recall on the
part of the patient. If the patient becomes
confused or cannot remember what is happening
during the seizure, then the seizure is classified as
a complex partial seizure.
complex partial seizures
These previously were called “psychomotor seizures”, “temporal
lobe seizures” or “limbic seizures”. These words are all synonyms.
Complex partial seizures may have an aura, which is a warning for the seizure, typically a familiar feeling (deja vu), nausea, heat
or tingling, or distortion of sensory perceptions.
About half of the patients do not have any remembered aura. During the complex partial seizure patients may fumble or
perform automatic fragments of activity such as lip smacking, picking at their clothes, walking around aimlessly, or saying
nonsense phrases over and over again. These purposeless
activities are called automatisms (lip smacking). About 75 percent of people
with complex partial seizures have automatisms. Those who do not simply stop, stare and blank out for a few seconds to minutes.
first aid for partial complex seizures
Do not restrain the person.
Remove dangerous objects from the person’s
path.
Calmly direct the person to sit down and guide
him or her from dangerous situations. Use force
only in an emergency to protect the person from
immediate harm, such as walking in front of an
oncoming car.
generalized seizures
These apparently start all over the brain. In fact,
epilepsy specialists believe that generalized
seizures originate in deep structures of the brain
and simply project to the cortical surface where
we can see the manifestations of the seizure
emerge relatively simultaneously.
absent seizures**
Were previously called petit mal seizures. Absence seizures
usually have onset in childhood, but they can persist into
adulthood. Absence seizures present with staring spells lasting
several seconds, sometimes in conjunction with eyelid fluttering
or head nodding. These seizures can be difficult to distinguish
from complex partial seizures that also may result in staring.
Absence seizures usually are briefer and permit quicker
recovery. *The EEG also helps to distinguish an absence from a
complex partial seizure.
myclonic seizure
This is a brief un-sustained jerk or series of jerks,
less organized than the rhythmic jerks seen
during a generalized tonic-clonic seizure. Other
specialized seizure types occasionally are
encountered.
tonic-clonic seizures
Were previously called grand mal seizures. These
seizures start with sudden loss of consciousness
and tonic activity (stiffening) followed by clonic
activity (rhythmic jerking) of the limbs. The patient’s eyes will roll up at the beginning of the seizure and the patient will typically emit a cry, not because of pain, but because of contraction
of the respiratory muscles against a closed throat.
generalized tonic-clonic
Generalized tonic-clonic seizures usually last one
to three minutes. The seizure itself is called an
ictus. After the seizure, the patient is “post-ictal”*:
sluggish, sleepy and confused, variably for
hours. Any seizure can have a postictal period.
tonic seizures
These involve stiffening of muscles as the primary seizure manifestation. Arms or legs may extend forward or up into the air. Consciousness may or may not be lost. By
definition, the clonic (jerking) phase is absent.
Classification can be difficult, because stiffening
is a feature of many complex partial
seizures. Tonic seizures, however, are much less
common than are complex partial or tonic-clonic
seizures.
atonic seizures
These are epileptic drop attacks. Atonic seizures
typically occur in children or adults with widespread brain injuries. People with atonic
seizures suddenly become limp and may fall to the ground. Football helmets are sometimes required to protect against serious injuries.
parenteral drug - barbs
Barbiturates, especially
phenobarbital, also amobarbital, pentobarbital sodium, and secobarbital sodium
barbs use
Eclampsia, status epilepticus,
severe recurrent seizures, tetanus,
anticonvulsant drug toxicity, other
convulsive states
parenteral drug - Phenytoin
Status epilepticus, seizure during
neurosurgery
parenteral drug - Magnesium sulfate
Severe toxemias of pregnancy
(preeclampsia and eclampsia)
parenteral Benzodiazepines: diazepam,
lorazepam, clonazepam***
***Status epilepticus; severe, recurrent
seizures; alcohol withdrawal
seizures
Factors to consider when choosing antiepileptic
drugs
Seizure type
Patient comorbidity and tolerance
Drug’s adverse effect/drug interaction profile
chosing antiepiliptic drugs
1) Assessment of seizure symptoms assists in the accurate
diagnosis and classification of the seizure type, which then
determines the
2) choice of the appropriate anticonvulsant drug therapy
3) There is a relationship between the patient’s age and the
onset and type of epileptic seizure state.
Two main pharmacologic effects of AEDs**
Increase motor cortex threshold to reduce its response to incoming electric or chemical stimulation
Depress or reduce spread of seizure discharge from its
focus or origin by depressing synaptic transport or
decreasing nerve conduction
Clinical effectiveness of AED therapy
Varies with the drug’s pharmacokinetics, mechanism of
action, and serum levels achieved
Influenced by genetic and environmental factors;
concomitant ailments, such as renal or hepatic
dysfunction; concurrent medication; diet; patient
compliance; and physical status
Dosing of certain drugs needs to be adjusted to obtain
optimal therapeutic effects; this dosage may vary
widely for patients
anti-epiliptic drugs, also known as
anticonvulsants
Goals of therapy
To control or prevent seizures while maintaining a
reasonable quality of life
To minimize adverse effects and drug-induced toxicity
AED therapy is usually lifelong (but not always!)
Combination of drugs may be used
Antiepileptic Drugs
Single-drug therapy
started before
multiple-drug therapy is tried
Serum drug concentrations must be measured
Therapeutic drug monitoring
Patients who are seizure free for 1 to 2 years may
be able to discontinue antiepileptic therapy
AED MOA
AED therapy must:
Prevent generation and spread of excessive electrical
discharge from abnormally functioning nerve cells
Protect surrounding normal cells
AED MOA con’t
Exact mechanism of action is not known
AEDs are thought to alter movement of sodium,
potassium, and calcium ions across nerve cells in
the brain
Reduce nerve’s ability to be stimulated
Suppress transmission of impulses from one nerve to the
next
Decrease speed of nerve impulse conduction within a
neuron
MOA overall effect
Neurons are stabilized
Neuron hyperexcitability
is decreased
Spread of excessive nerve
impulses is decreased
Antiepileptic Drugs:Indications
Prevention or control of seizure activity
Long-term maintenance therapy for chronic,
recurring seizures
Acute treatment of convulsions and status
epilepticus
Other uses
numerous adverse effects
Numerous adverse effects—vary per drug
Adverse effects often necessitate a change in
medication
Black box warning as of 2008
Suicidal thoughts and behavior
e.g. Long-term therapy with phenytoin may cause
gingival hyperplasia, acne, hirsutism, and Dilantin
facies (swollen and round faces)
Antiepileptic Drugs
Barbiturates, such as phenobarbital (Luminal®)
carbamazepine (Tegretol®)
valproic acid (Depakene®)
felbamate (Felbatol®)
Hydantoins, such as phenytoin (Dilantin®) and
fosphenytoin
First-Line Therapy for Seizure Control
Carbamazepine (Tegretol®)
Phenytoin (Dilantin®)
fosphenytoin
Valproate (Depakote®)
