Chapter+19 Antiseizure Meds

Page 1: CHAPTER 19

Antiseizure Drugs

Page 2: Understanding Epilepsy

Definition

• Epilepsy = A condition where the brain sends abnormal electrical signals, causing seizures.

• Seizures can lead to:

  • Fainting or blacking out (loss of consciousness).

  • Uncontrolled shaking or jerking movements.

Causes of Seizures:

• Brain injuries (from accidents, strokes, or lack of oxygen).

• Infections (like meningitis).

• Low blood sugar or imbalance in body salts (electrolytes K or Magnesium).

• Fever, stress, alcohol, or drug use can also trigger seizures.

• Isolated seizures may arise from:

  • Fever

  • Stress

  • Hypoglycemic reaction

  • Electrolyte or acid-base imbalance

  • Alcohol or drugs

    Example: A child with a high fever might have a seizure (febrile seizure), but this doesn’t mean they have epilepsy.

Page 3: Seizure Classifications

1. Generalized Seizures (affect the whole brain):

• Tonic-Clonic (Grand Mal) Seizure:

  • Most common type.

  • Stiffening of muscles (tonic phase) → then jerking movements (clonic phase).

  • Example: A person suddenly collapses, their body stiffens, then they start shaking.

• Absence (Petit Mal) Seizure:

  • Briefly loses awareness, looks like daydreaming.

  • Common in children.

  • Example: A child suddenly stops talking for a few seconds, then continues like nothing happened.

2. Partial Seizures (affect one part of the brain):

• Psychomotor Seizures:

  • Repetitive movements like chewing or swallowing.

  • Behavior changes (acting confused or dazed).

  • Example: Someone may randomly smack their lips and not remember doing it.

    (phone pic at 714)

Page 4: Antiseizure Drugs Overview

Purpose: These medications help prevent seizures by controlling brain activity.

• How they work: They stabilize nerve cells so they don’t send out uncontrolled signals.

• Three main actions:

  1. Block sodium (Na⁺) from entering nerve cells → Stops overactive signals.

  2. Block calcium (Ca²⁺) from entering nerve cells → Helps control seizures.

  3. Increase GABA levels → GABA is a brain chemical that calms nerves.

Example: Think of a seizure as a phone ringing nonstop in the brain. Antiseizure drugs silence the call so the brain can function normally.

Page 5: Phenytoin

Action

• How it works:

  • 🔒 Blocks sodium from rushing into brain cells

  • 🧠 This keeps the brain cells calm

  • ⚡ And it stops them from firing too much or too fast

  • Prevents repeated brain signals → Stops seizures.

• Common Side Effects:

  • Swollen gums (gingival hyperplasia) → Important to maintain good oral hygiene.

  • Unsteady movement (ataxia), dizziness, drowsiness.

  • Headaches, confusion, depression.

  • Purple Glove Syndrome (rare but serious: swelling and skin discoloration).

  • Stomach issues (constipation, nausea).

  • Changes in heart rate (slow or fast heartbeat).

Example: Someone taking Phenytoin should brush their teeth carefully because of the risk of gum overgrowth.

Page 6: Phenytoin Interactions and Contraindications

Drugs that make Phenytoin stronger (increase effects):

• Cimetidine (for stomach ulcers)

• Sulfonamides (a type of antibiotic)

• Drugs that make Phenytoin weaker (decrease effects):

  • Antacids (like Tums)

  • Calcium supplements

  • Certain herbs (primrose, ginkgo)

• Phenytoin can increase the effects of:

  • Blood thinners (like aspirin & anticoagulants) → Higher risk of bleeding.

Important Warnings:

• Not safe for pregnancy → Can harm the baby (teratogenic).

• Safe blood level range = 10-20 mcg/mL (too low = seizures, too high = toxicity).

Example: A patient taking Phenytoin should avoid antacids because they can make the drug less effective.

Page 7: Barbiturates

Example: Phenobarbital

• How it works:

  • Boosts GABA, which calms brain activity and prevents seizures.

• Used for:

  • Tonic-Clonic (Grand Mal) seizures

  • Partial seizures

  • Myoclonic seizures (sudden muscle jerks)

  • Status Epilepticus (seizures that don’t stop)

• Therapeutic Range: 15-40 mcg/mL

• Side Effects:

  • Drowsiness, sedation (makes people feel very sleepy).

  • Can build tolerance over time (patient may need a higher dose).

• Stopping the drug: Must be done gradually to avoid withdrawal symptoms.

Example: A patient on Phenobarbital should not drive because it can cause extreme drowsiness.

Page 8: Succinimide

Example: Ethosuximide

• How it works:

  • Blocks calcium (Ca²⁺) from entering nerve cells, which helps stop seizures.

• Used for:

  • Absence seizures (brief loss of awareness).

• Therapeutic Range: 40-100 mcg/mL

• Serious Side Effects:

  • Blood disorders (low red or white blood cells).

  • Lupus-like symptoms (fatigue, joint pain, rash).

  • Severe mental health effects (psychosis, suicidal thoughts).

Example: If a patient on Ethosuximide starts feeling depressed or seeing things that aren’t there, they should call their doctor immediately.

Page 9: Benzodiazepines

Examples:

• Clonazepam – Used for absence & myoclonic seizures (can stop working after 6 months).

• Clorazepate – Used for partial seizures.

• Diazepam – Used for status epilepticus (continuous seizures).

• Diazepam (Valium) Facts:

  • Given through IV for emergency seizures.

  • Short-acting, so another antiseizure drug must be given afterward.

Example: A patient having a seizure that won’t stop in the hospital may be given IV Diazepam first, followed by Phenytoin to prevent more seizures.

Diazepam have to be given with another medication for example the longer-acting Lorazepam, which helps to maintain seizure control after the initial treatment. or phenytoin, which can be administered orally or intravenously, to ensure sustained seizure prevention and management.

Page 10: Iminostilbene

Example: Carbamazepine

• Used for:

  • Tonic-Clonic and Partial seizures

  • Bipolar disorder (helps stabilize mood).

  • Trigeminal neuralgia (severe facial pain).

• Therapeutic Range: 4-12 mcg/mL

Example: A patient with seizures and bipolar disorder might take Carbamazepine because it treats both conditions.

Page 11: Valproate

Example: Valproic Acid

• Used for:

  • Tonic-Clonic, Absence, and Partial seizures (covers multiple seizure types).

• Therapeutic Range: 50-100 mcg/mL

• Side Effects:

  • Dizziness, drowsiness, weakness.

  • Double vision (diplopia).

  • Stomach problems (GI distress).

  • Suicidal thoughts.

  • Low platelet count (thrombocytopenia) → Risk of bleeding.

Example: A patient on Valproic Acid should have regular blood tests to check platelet levels and prevent bleeding problems.

Page 12: Antiseizure Drugs and Pregnancy

• Seizures during pregnancy are dangerous for both mother and baby.

• 1 in 3 women with epilepsy has a higher risk of complications.

• Many antiseizure drugs are teratogenic (can harm the baby).

Effects on Pregnancy:

• Vitamin K deficiency → Can cause bleeding in newborns.

  • Solution: Give Vitamin K to the mother before birth or to the baby after birth.

• Folate (Folic Acid) loss → Can cause birth defects.

Example: A pregnant woman on antiseizure drugs may need extra folic acid to protect the baby’s development.

Page 13: Antiseizure Drugs and Febrile Seizures

• Febrile seizures = Seizures caused by fever (common in young children, ages 3 months - 5 years).

• Not the same as epilepsy (most kids don’t develop long-term seizure disorders).

Treatment for high-risk cases:

• Phenobarbital or Diazepam may be given to prevent future seizures.

Example: A child with repeated febrile seizures might be prescribed Diazepam to lower seizure risk during fevers.

Page 14: Antiseizure Drugs and Status Epilepticus

Status Epilepticus = A medical emergency where a seizure does not stop or multiple seizures happen back-to-back.

• Needs immediate treatment to prevent brain damage or death.

Treatment Plan:

1. First-line drugs (to stop seizures fast):

   • Diazepam (Valium) or Lorazepam (Ativan) – given IV.

   • These drugs work quickly by boosting GABA, a calming brain chemical, to stop the seizure immediately.

   • If the seizure isn’t stopped right away, it can cause brain damage, lack of oxygen, or death.

2. Follow-up drug (to prevent more seizures):

   • Phenytoin IV.

   • Phenytoin takes longer to start working, so it won’t stop an ongoing seizure but helps prevent future ones.

   • That’s why Diazepam or Lorazepam is given first, then Phenytoin is used to keep more seizures from happening.

3. If seizures continue:

   • Midazolam or Propofol IV (strong sedatives to shut down seizure activity).

4. Important: Give IV drugs slowly to avoid breathing problems.

Example: If a patient in the ER is having nonstop seizures, the nurse will first give Diazepam IV to stop it fast, then Phenytoin IV to prevent more seizures from happening.

Page 15: Clinical Judgment: Phenytoin

Concept: Intracranial regulation (how the brain controls its functions).

• Recognize cues (what to assess before giving Phenytoin):

  • Ask about current medications & herbal supplements (some interact).

  • Check kidney & liver function (Phenytoin is processed in the liver).

• Prioritize issues (main concerns):

  • Risk of injury & falls (drowsiness, dizziness).

  • Need for patient education (to prevent side effects & toxicity).

• Goal: Reduce seizure frequency and keep drug levels safe.

Example: A nurse should check liver function tests before starting a patient on Phenytoin, since the liver processes the drug.

Page 16: Clinical Judgment: Phenytoin (Continued)

Take Action

• What to Monitor & Teach Patients:

✅ Check Phenytoin levels regularly to keep them in the therapeutic range (10-20 mcg/mL).
✅ Female patients on birth control: Phenytoin can make birth control less effective, so they should use an additional contraceptive method.
✅ Seizure precautions: If a patient is at risk for seizures, make sure:

• Bed rails are padded.

• The patient is monitored closely.
  ✅ No driving or operating heavy machinery when starting Phenytoin (can cause dizziness and drowsiness).

Example: A patient taking Phenytoin should use another form of birth control since it can make oral contraceptives less effective.

Page 17: Practice Question

Question

• Before giving Phenytoin, what is MOST important for the nurse to do?

  A. Maintain the patient on bed rest.
  B. Check Phenytoin levels. ✅ (Correct Answer)
  C. Monitor intake and output.
  D. Monitor renal function tests.

  💡 Why?
  Phenytoin has a narrow therapeutic range (10-20 mcg/mL), so checking drug levels is crucial to prevent toxicity or underdosing.

Page 18: Practice Question

Question

• A patient was discharged 3 days ago on Phenytoin therapy for seizures. They come to the ER experiencing seizures. What is the most valuable test to determine why?

  A. A CT scan
  B. An EEG
  C. Serum Phenytoin levels ✅ (Correct Answer)
  D. Serum electrolytes

  💡 Why?

  • The patient was recently started on Phenytoin, so the first thing to check is whether their drug level is too low (below 10 mcg/mL), which could allow seizures to occur.

  • A CT scan or EEG might help later, but checking Phenytoin levels is the most immediate and important step.

Page 19: Practice Question

Question

• Which sign suggests an adverse reaction to Phenytoin therapy?

  A. Thrombocytopenia (low platelet count – bleeding risk) ✅ (Correct Answer)
  B. Leukocytosis (high white blood cell count)
  C. Gingival atrophy (not a known side effect; gum overgrowth is, though!)
  D. Hypoglycemia (low blood sugar)

  💡 Why?

  • Thrombocytopenia can cause easy bruising and bleeding, which is a serious side effect.

  • Gingival hyperplasia (swollen gums) is common with Phenytoin, but gingival atrophy (gum shrinking) is incorrect.

Page 20: Practice Question

Question

• A patient is experiencing status epilepticus. The nurse anticipates immediate administration of which drug?

  A. Phenobarbital
  B. Phenytoin
  C. Valproic acid
  D. Diazepam ✅ (Correct Answer)

  💡 Why?

  • Diazepam (or Lorazepam) is given first in status epilepticus because it works quickly to stop the seizure.

  • Phenytoin is given next to prevent more seizures, but it doesn’t work fast enough to stop one that’s already happening.

  • Phenobarbital and Valproic Acid are used for seizures, but they aren’t the first choice in an emergency.

  Example: If a patient is having a prolonged seizure, the nurse should expect to give IV Diazepam first, then Phenytoin after to maintain seizure control.