Drugs for Seizures Chapter 15

1. 15 Drugs for Seizures Chapter 15 (“analeptics”)

2. OVERVIEW: Neuro System escitalopram (Lexapro) Tri-Cyclic Antidepressant Antidepressant / Anxiolytic MAOIs Benzodiazepines lorazepam (Ativan) diazepam (Valium) GABA Antagonist zolpidem (Ambien) A phenytoin (Dilantin) valproic acid (Depakote) Phenytoin-Like Drugs Succinimides ethosuximide (Zarontin) phenobarbital (Luminal) Barbiturates Phenothiazines chlorpromazine (Thorazine) Non-Phenothiazines halperidol (Haldol) Opioids morphine (Infumorph) Atypical Antipsychotics risperidone (Risperdal) aspirin (ASA) Salicylates ibuprofen (Motrin) NSAIDs acetaminophen (Tylenol) Non-Opioid tramadol (Ultram) Central Acting ergotamine (Cafergot) Sumatriptan (Imitrex) Anti-Migraine Opioid Antagonists naloxone (Narcan)

3. Learning Outcomes • 1. Describe the nurse’s role in the pharmacologic management of seizures of an acute nature and epilepsy. • 2. Categorize drugs used in the treatment of seizures based on their classification and mechanism of action. • 3. Use the nursing process to care for patients receiving drug therapy for epilepsy and seizures. • 4. For each of the drug classes, know representative drug examples and explain their mechanism of drug action, primary actions, and important adverse effects.

4. Anti-seizure Pharmacotherapy • Goal: suppress neuronal activity enough to prevent abnormal or repetitive firing • Drugs act through three mechanisms: • Stimulating an influx of chloride ions • Delaying an influx of sodium • Delaying an influx of calcium • Directed at controlling movement of electrolytes across neuronal membranes or affecting neurotransmitter balance • Some drugs act by more than one mechanism

5. Pharmacotherapy Illustrated: Model of the GABA Receptor–Chloride Channel Molecules in Relationship to Antiseizure Pharmacotherapy

6. Barbiturates and GABA Agents Monitor Patient’s condition Liver and kidney function Pregnancy Category D Common side effects

7. Patient Teaching Use reliable contraception Immediately report pregnancy Report excessive signs of bleeding Report drowsiness and bone pain

8. Drugs that Potentiate GABA Action Act by changing the action of gamma-aminobutyric acid (GABA), the primary inhibitory neurotransmitter in the brain Predominate effect of GABA potentiation is CNS depression

10. Benzodiazepines—Schedule IV Drug Monitor for drug-abuse potential Pregnancy risk—Pregnancy Category D Contraindicated in narrow-angle glaucoma Respiratory depression may result with other CNS depressants. Common side effects include dizziness, drowsiness Overdose—give flumazenil (Romazicon)

11. Patient Teaching Avoid alcohol, OTC drugs, and herbal medications Avoid nicotine Avoid driving and hazardous activities Rebound seizures if discontinued abruptly Take with food Drug often used illegally

12. Hydantoin and Phenytoin-like Drugs Monitor serum-drug levels Monitor for signs of toxicity Monitor for blood dyscrasias and bleeding disorders Monitor liver and kidney function Fatal hepatotoxicity can occur

13. Hydantoin and Phenytoin-like Drugs Contraindications Patients with hypersensitivity to hydantoin products should be cautious. Rash, seizures due to hypoglycemia, sinus bradycardia, and heart block

14. Patient Teaching Routine labs for serum level Routine labs for liver and kidney function Immediately report signs of toxicity Immediately report unusual bleeding Immediately report liver or brain disease Immediately report heart block, hypoglycemia, or pregnancy

15. Succinimides Do not abruptly withdraw medication Use with caution with antiseizure medications, phenothiazines, and antidepressants Pregnancy risk—pregnancy Category C

16. Common Adverse Reactions Drowsiness, headache, fatigue, dizziness Depression or euphoria Nausea, vomiting, weight loss Abdominal pain

17. Life-Threatening Reactions Severe mental depression with suicide intent Stevens-Johnson syndrome Blood dyscrasias

18. Patient Teaching Immediately report mood changes or suicidal thoughts Avoid driving and hazardous activities Do not suddenly stop taking Take with food Report symptoms of fever or sore throat Report weight loss and anorexia

19. Dosage Procedure Start with smallest initial dose Add additional drugs, if necessary Ensure compatibility with other medications Monitor serum-drug levels

20. Withdrawal of Antiseizure Medications Should be seizure free at least three years Withdraw gradually over several months Resume medications if seizures return Be aware of rebound seizures

21. Drugs That Potentiate GABA Action Barbiturates Benzodiazepines Miscellaneous GABA agents

22. Barbiturates Prototype drug: phenobarbital (Luminal) Mechanism of action: changing the action of GABA Primary use: controlling seizures Adverse effects: dependence, drowsiness, vitamin deficiencies, laryngospasm

23. Prototype Drug: Phenobarbital (Luminal)

24. Benzodiazepines Prototype drug: diazepam (Valium) Mechanism of action: similar to that of barbiturates but safer Primary use: for short-term seizure control Adverse effects: drowsiness and dizziness

25. Prototype Drug: Diazepam (Valium)

26. Diazepam Animation Click here to view an animation on the topic of diazepam.

27. Hydantoins Prototype drug: phenytoin (Dilantin) Mechanism of action: to densitize sodium channels Primary use: treating all types of epilepsy except absence seizures Adverse effects: CNS depression, gingival hyperplasia, skin rash, cardiac dysrhythmias, and hypotension

29. Prototype Drug: Phenytoin (Dilantin)

30. Prototype Drug: Phenytoin (Dilantin)

31. Phenytoin-Like Drugs Prototype drug:Valproic acid (Depakene) Mechanism of action:to desensitize sodium channels Primary use:for absence seizures Adverse effects:limited CNS depression, visual disturbances, ataxia, vertigo, headache Additional adverse reactions:gastrointestinal effects, hepatotoxicity, pancreatitis

32. Valproic Acid Animation Click here to view an animation on the topic of valproic acid.

33. Prototype Drug: Valproic Acid (Depakene, Depakote)

34. Succinimides Prototype drug:ethosuximide (Zarontin) Mechanism of action:suppress calcium influx Primary use:for absence seizures Adverse effects:rare but include drowsiness, dizziness, lethargy Very rare but serious side effects:systemic lupus erythematosis, leukopenia, aplastic anemia, Stevens-Johnson syndrome

35. Prototype Drug: Ethosuximide (Zarontin)

36. Drugs That Potentiate GABA Action Include barbiturates, benzodiazepines, and miscellaneous GABA agents Suppress the firing ability of neurons

37. Treating Seizures with Barbituates Low margin for safety High potential for dependence, and they cause Profound CNS depression Overall effective against all major seizure types except absence seizures

38. Examples of Barbiturates Phenobarbital (Luminal) Amobarbital (Amytal) Secobarbital (Seconal) Pentobarbital (Nembutal)

39. Treating Seizureswith Benzodiazepines Indications include absence seizures and myoclonic seizures Tolerance may develop quickly one of most widely prescribed classes, used also for anxiety, skeletal muscle spasms, and alcohol withdrawal symptoms

40. Examples of Benzodiazepines Clonazepam (Klonopin) Clorazepate (Tranxene) Lorazepam (Ativan) Diazepam (Valium)

41. Newer GABA-related Drugs Gabapentin (Neurontin) Pregabalin (Lyrica) Tiagabine (Gabitril) Topiramate (Topamax)

42. Hydantoin and Newer Drugs Delay an influx of sodium ions across neuronal membranes Sodium movement is factor that determines whether neuron will undergo an action potential Sodium channels are not blocked; they are just desensitized

43. Treating Seizures With Hydantoins and Related Drugs Useful in treating all types of epilepsy except absence seizures Provides effective seizure suppression, without the abuse potential or CNS depression associated with barbiturates Phenytoin-related drugs used less frequently

44. Examples of Hydantoins Phenytoin (Dilantin)—most common Fosphenytoin (Cerebyx)

45. Examples of Phenytoin-like Drugs Carbamazepine (Tegretol)—tonic-clonic and partial seizures Felbamate (Felbatol) Lamotrigine (Lamictal) Valproic acid (Depakene, Depakote)—absence seizures Zonisamide (Zonegran)

46. Treating Seizures with Succinimides Suppress seizures by delaying calcium influx into neurons Generally only effective against absence seizures Ethosuximide (Zarontin) is the most commonly prescribed drug in this class

47. Succinimides Examples of succinimides Ethosuximide (Zarontin) Methsuximide (Celontin) Phensuximide (Milontin)

48. NCLEX-RN ReviewQuestion 1 The nurse evaluates patient teaching related to causes of seizures. Further teaching is needed if the patient makes which of the following statements? • “Seizures can be caused by inflammation of the brain.” • “Seizures can be caused by low blood sugar.” • “My relative had seizures because of a large tumor growing in his muscles.” • “Seizures may occur after a head injury.”

49. NCLEX-RN ReviewQuestion 1 – Answer “Seizures can be caused by inflammation of the brain.” “Seizures can be caused by low blood sugar.” “My relative had seizures because of a large tumor growing in his muscles.” “Seizures may occur after a head injury.”

50. NCLEX-RN ReviewQuestion 1 – Rationale Rationale: Seizures may be caused by inflammation, head injuries, or low blood sugar levels. Rapid-growing, space-occupying lesions in the brain, which increase intracranial pressure, may cause seizures, but not tumors, within the muscles.