Anticonvulsants

=** Anticonvulsants **=  =** Types of epileptic seizures and Clinical Manifestations ** 1.) **Partial seizures** -involve one side of the brain at onset A.)**Simple partial seizure**- pt. is conscious, limited to certain muscles or, specific sensory changes. B.)**Complex partial seizure**- pt. is conscious and impaired, experiences automatism (involuntary, and repetitive movements), autonomic dysregulation, psychotic like behavior (pt. may see aura beforehand). C.) **Partial seizures** that evolve to general seizures; see generalized seizures for clinical manifestations. 2.) **Generalized seizures**- involves both sides of the brain at onset A.)**Tonic -clonic seizure** (grand mal)- pt. is unconscious, loss of postural tone, tonic clonic contraction of skeletal muscles bilaterally (pt. may see aura). B.) **Absent seizure** (petit mal)- pt. is conscious but impaired (very short 5-10 sec.), most common in children, postural muscles not impaired, pt. experiences minor muscular twitching (eyelids or face). C.) **Myoclonic seizures**- pt. experiences sudden, brief contractions of individual muscles or groups producing shock like spasms in muscles of the face, trunk, and extremities. D.) **Clonic seizures**- pt. experiences repetitive clonic jerking, that can alternate between opposing muscles. E.)**Tonic seizures**- pt. experiences violent simultaneous muscular contractions (flexors and extensors), while limbs are in a strained position. F.) **Atonic seizures** (astatic)- pt. experiences sudden loss of muscle tone and consciousness (pt. sustain fall injuries). 3.) **Unclassified seizures**- cannot be classified because of insufficient data or atypical pattern of seizure -Anticonvulsants are CNS drugs -CNS (Depressed function, tolerance to the sedative effect, impaired learning & cognitive abilities) Gastrointestinal tract (Anorexia, Nausea, Vomiting) Dermatologic (Rash, Stevens-Johnson syndrome, Exfoliative dermatitis, Erythema multiforme, Drug induced systemic lupus erythematosus) Withdrawal- Abrupt withdrawal can cause seizures Categories of Anticonvulsant Drugs: 

-Phenytoin (Dilantin) -Uses- Tonic -clonic seizures and partial seizures, Trigeminal neuralgia, Antiarrhythmic -Adverse Reactions- Gastrointestinal, CNS (Mental confusion, Ataxia, Slurred speech, Blurred vision, Dizziness, Insomnia)Dermatologic (Rash, Exfoliative dermatitis, Lupus erythematosus, Stevens-Johnson syndrome, Irreversible hypertrichosis, Hirsutism) Vitamin deficiency (Vitamin D and folate, Interferes with vitamin D metabolism) Congenital abnormalities, Gingival enlargement. When given intraven ously-. thrombophlebitis, arrythemia, hypotension. Absorbtion- GI tract  > (Phenobarbital) > -Uses: Treatment of tonic-clonic seizures and partial seizures > -Adverse Reactions- Sedation, Dermatologic (Exfoliative dermatitis, Erythema multiforme, Stevens-Johnson syndrome) 
 * 1) Hydantions:
 * Babiturates:

> (Tegretol) > -Other Uses: Trigeminal neuralgia, bipolar depression > -Pharmacologic effects- Anticonvulsant, Anticholinergic, Antidepressant, Sedative, Muscle relaxant, Antiarrhythmic , Antidiuretic , Neuromuscular transmission inhibitory actions > -Mechanism of action- Blocks sodium channels therefore blocks propagation of nerve impulses (LA). Also, inhibits high-frequency repetitive firing of neurons > -Adverse reactions- CNS depression (Dizziness, Headaches, Vertigo, Nystagmus, Drowiness, Speech disturbances, Fatigue, Ataxia, Confusion) Gastrointestional tract (Vomiting, Nausea, Abdominal pain, Diarrhea, Constipation, Anorexia) Hematologic (Aplastic anemia, agranulocytosis, thrombocytopenia and leucopenia) Dermatologic (Rashes, Urticaria, Photosensitivity reactions, Altered skin pigmentation, Erythema multiforme, erythema nodosum, and systemic lupus erythematous) Oral (Xerostomia, Glossitis , Stomatitis) Other (Congestive heart failure, Abnormal liver function ) 
 * Carbamazepine:

> (dipropylacetic acid) > -Pharmacologic effects-Anticonvulsant (used especially for abscence seizures), Antidepressant (used in bi-polar disorder), and reduction of migrane headaches. > -Absorbtion: GI tract > -Adverse effects: Appetite distubances, indigestion, heartburn, nausea, and weight change. > > (Ethosuximide, methsuximide) > -Pharmacologic effects: Anticonvulsant (Abssence seizures) > -Mechanism of action: Inhibiion of low threshold Ca+ channels (not fully understood) > -Absorption: GI tract, metabolized in liver, excreted: urine > -Adverse effects: gastrointestinal distress, headache, dizziness, and skin rash. Potential fatal bone marrow depression. > Patient with hematopoietic toxicity Adverse effects: fever, sore throat and coagulopathy.  > Drugs that affect the GABA transmission: Such as: Benzodiazepines, Vigabatrin, Tiagabine Neurosteriods, and GABAmimetic agents > Miscellaneious Anticonvulsants: Such as Gagapentin, Febamate, Lamotrigine, Carbonic Anhydrase Inhibitors, Topiramate, Zonisamide, Levetiracetam, Magnesium Salts.
 * <span style="font-family: 'Comic Sans MS', cursive; font-size: 120%;">Valproic Acid:
 * <span style="font-family: 'Comic Sans MS', cursive; font-size: 110%;">Succinimides: <span style="font-family: 'Comic Sans MS', cursive; font-size: 120%;">

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 * Partial seizures:
 * **Simple partial:**
 * carbamazepine (Tegretol)
 * phenytoin (Dilantin)
 * phenobarbital (Luminal)
 * primidone (Mysoline)
 * valproic acid (Depakene, Depakote)
 * gabapentin (Neurontin)
 * lamotrigine (Lamictal)
 * **Complex partial**
 * carbamazepine (Tegretol)
 * phenobarbital (Luminal)
 * phenytoin (Dilantin)
 * primidone (Mysoline)
 * valproic acid (Depakene, Depakote)
 * lamotrigine (Lamictal)
 * **Partial is secondarily generalized tonic-clonic seizures**
 * carbamazepine (Tegretol)
 * phenobarbital (Luminal)
 * phenytoin (Dilantin)
 * primidone (Mysoline)
 * valproic acid (Depakene, Depakote)
 * gabapentin (Neurontin)
 * lamotrigine (Lamictal)
 * Antiepileptic drugs side effect profiles
 * M**ost antiseizure medications tend to be sedating, with drowsiness observed.**
 * **Often sedative effect diminish over time.**
 * **Other common side effects are referable to the gastrointestinal tract.**
 * **For most antiseizure agents, there are low frequency, but serious side effects.**
 * **Primidone (Mysoline)/phenobarbital (Luminal) side effects:**
 * sedation
 * vertigo, nausea, vomiting, ataxia, nystagmus, diplopia. Feeling of intoxication immediately after ingestion.
 * Serious adverse effects are uncommon but include rash, leukopenia, thrombocytopenia, lupus, and lymphadenopathy.
 * Megaloblastic anemia which response to folate
 * Osteomalacia (response to high dose vitamin D)
 * Hypoprothrombinemia with hemorrhage in newborns of primidone (Mysoline)-treated mothers (vitamin K is effective for treatment or prophylaxis)
 * **Carbamazepine (Tegretol):**
 * Acute intoxication: stupor, coma, hyperirritability, convulsions, and respiratory depression
 * Long-term: drowsiness, vertigo, blurred vision
 * Serious hematological toxicity: aplastic anemia, agranulocytosis
 * **Ethosuximide (Zarontin):**
 * The most common complaint is gastrointestinal upset, including nausea, vomiting and anorexia, and CNS effects including drowsiness, euphoria, headache and hiccough. Some tolerance of these effects may develop.
 * Hematological disturbances include: leukopenia, thrombocytopenia and aplastic anemia. Bone marrow depression may be fatal, although very infrequently so.
 * Skin reactions, including Stevens-Johnson syndrome and exfoliative dermatitis have been reported

__ Types of seizures __

Those that respond to pharmacotherapy: **Tonic-clonic seizures:** include all the body, muscle rigidity, violent muscle contractions, and loss of consciousness.
 * Absence seizures:** “petite mal” usually in children, it temporary disturbance of brain function, abrupt short-term lack of conscious activity (“absence”).
 * Status epilepticus**: an acute or prolonged epileptic crisis there is a change in mental status.

Those that do not respond to pharmacotherapy:


 * Myoclonic seizures**: are abnormal bilateral movements of the body, they are brief jerking movements that are either subtle or very dramatic.
 * Atonic seizures**: usually begin in childhood, it is a brief lapse in muscle tone and many fall, sometimes called drop attacks, or drop seizures.