1. Introduction to Clinical Pharmacology Chapter 29 Antiepileptics

2. Drugs Used for Managing Seizure Disorders
Antiepileptics
The drug categories used as antiepileptics are the hydantoins, carboxylic acid derivatives, succinimides, oxazolidinediones, benzodiazepines, and non-specified drugs.

3. Antiepileptics: Actions #1
Hydantoins stabilize the hyperexcitability postsynaptically in the motor cortex of the brain.
Carboxylic acid derivatives increase levels of gamma (γ)-aminobutyric acid (GABA), which stabilizes cell membranes.
Succinimides depress the motor cortex, creating a higher threshold before nerves react to the convulsive stimuli.

4. Antiepileptics: Actions #2
Oxazolidinediones decrease repetitive synaptic transmissions of nerve impulses.
Benzodiazepines elevate the seizure threshold by decreasing postsynaptic excitation.
Non-specified drugs have differing properties; for example, gabapentin is a GABA agonist, and topiramate blocks the seizure activity rather than raising the threshold.

5. Antiepileptics: Uses
Used prophylactically to prevent seizures following trauma, neurosurgery, or tumor
Used in treatment of:
Seizures of all types; neuropathic pain; bipolar disorders; anxiety disorders

6. Antiepileptics: Adverse Reactions
Central nervous system reactions: drowsiness; weakness; dizziness; headache; somnolence; nystagmus; ataxia; slurred speech
Gastrointestinal reactions: nausea; vomiting; anorexia; constipation; diarrhea; gingival hyperplasia, acute liver failure with felbamate
Other: skin rashes; pruritus; urticaria; urinary frequency; serious skin reactions; hematologic changes

7. Antiepileptics: Contraindications #1
Contraindicated in patients hypersensitive to the drugs
Phenytoin is contraindicated in patients with sinus bradycardia; with sinoatrial block; with Adams–Stokes syndrome; with second- and third-degree atrioventricular (AV) block; during pregnancy and lactation
Ethotoin (Peganone) is contraindicated in patients with hepatic abnormalities

8. Antiepileptics: Contraindications #2
Succinimides are contraindicated in patients with bone marrow depression or hepatic or renal impairment
Carbamazepine is contraindicated in patients with bone marrow depression or hepatic or renal impairment and during pregnancy
Valproic acid (Depakote) is not administered to patients with renal impairment or during pregnancy
Oxcarbazepine may exacerbate dementia

9. Antiepileptics: Precautions #1
Used cautiously in patients with liver or kidney disease and neurologic disorders
The newer medications such as elicarbazepine and oxcarbazepine can cause hyponatremia.
Benzodiazepines are used cautiously during pregnancy and in patients with psychoses; patients with acute narrow-angle glaucoma; elderly or debilitated patients

10. Antiepileptics: Precautions #2
Phenytoin is used cautiously in patients with hypotension; severe myocardial insufficiency; hepatic impairment
Trimethadione is used with caution in patients with eye disorders
Miscellaneous antiepileptics are used cautiously in patients with glaucoma or increased intraocular pressure; a history of cardiac, renal, or liver dysfunction; and psychiatric disorders

11. Antiepileptics: Interactions #1
Interacting drug
Effect of interaction
Antibiotics/antifungals
Increased effect of anticonvulsant
Tricyclic antidepressants
Salicylates
Cimetidine
Theophylline
Decreased serum levels of anticonvulsant

12. Antiepileptics: Interactions #2
Interacting drug
Effect of interaction
Antiseizure medications
May increase seizure activity
Protease inhibitors
Increased carbamazepine levels resulting in toxicity
Oral contraceptives
Decreased effectiveness of birth control, resulting in breakthrough bleeding or pregnancy
Analgesics or alcohol
Increased depressant effect
Antidiabetic medications
Increased blood glucose levels

13. Nursing Process: Assessment #1
Preadministration assessment:
Obtain vital signs at the time of the initial assessment to provide baseline data
Thorough patient history is necessary to identify type of seizure disorder
Primary health care provider may order laboratory and diagnostic tests

14. Nursing Process: Assessment #2
Ongoing assessment:
Carefully document each seizure with regard to time of occurrence; duration of seizure; psychic or motor activity occurring before, during, after seizure
Dosage adjustments are based on patient’s response to therapy, as well as occurrence of adverse reactions
Serum plasma levels of anticonvulsant are measured regularly to monitor for toxicity

15. Nursing Diagnoses
Risk for Injury related to seizure disorder, drowsiness, ataxia, and vision disturbances
Risk for Impaired Skin Integrity related to adverse reactions (rash)
Risk for Infection related to immunosuppression secondary to drug therapy
Impaired Oral Mucous Membranes related to gum overgrowth secondary to hydantoins

16. Nursing Process: Planning
Expected outcomes for patient depend on the type and severity of the seizure but may include:
Optimal response to therapy
Support of patient needs related to management of adverse reactions
Understanding of and compliance with prescribed therapeutic regimen

17. Nursing Process: Implementation #1
Promoting an optimal response to therapy:
Make notation on the care plan and inform all health care team members of the importance of the drug
Barbiturates:
Monitor patient carefully during administration of barbiturate, taking blood pressure and observing respirations frequently

18. Nursing Process: Implementation #2
Promoting an optimal response to therapy (cont.)
Benzodiazepines:
Dosage of benzodiazepines is highly individualized; increase the dosage cautiously to avoid adverse reactions, particularly in elderly and debilitated patients
Do not mix diazepam with other drugs

19. Nursing Process: Implementation #3
Promoting an optimal response to therapy (cont.)
Hydantoins:
Monitor serum concentrations of drug on regular basis to detect signs of toxicity
Oxazolidinediones:
Used when less toxic drugs are not effective in controlling seizure disorder

20. Nursing Process: Implementation #4
Promoting an optimal response to therapy (cont.)
Succinimides:
Effective in controlling partial seizures; these drugs are given with food to prevent GI upset
Miscellaneous antiepileptics:
Drug is absorbed rapidly when taken orally, should not be chewed but swallowed whole

21. Nursing Process: Implementation #5
Monitoring and managing patient needs:
Risk for injury:
Assist the patient with all ambulatory activities
Use caution when giving an oral preparation as aspiration of tablet, capsule, or liquid may occur if patient experiences drowsiness
Test swallowing ability of patient by offering small sips of water before giving drug

22. Nursing Process: Implementation #6
Monitoring and managing patients needs (cont.)
Risk for impaired skin integrity:
Carefully examine all affected areas and provide an accurate description
Be alert for signs of pancytopenia, such as sore throat, fever, general malaise, bleeding of the mucous membranes, epistaxis, easy bruising
Routine laboratory tests, such as complete blood counts and differential counts, should be performed periodically

23. Nursing Process: Implementation #7
Monitoring and managing patient needs (cont.)
Impaired oral mucous membranes:
Periodically inspect mouth, teeth, gums of patients in a hospital or long-term clinical setting

24. Nursing Process: Implementation #8
Educating the patient and family:
When patient receives diagnosis of epilepsy, nurse must assist patient and family to adjust to diagnosis
Instruct family members in care of patient before, during, and after seizures
Explain importance of restricting some activities until seizures are controlled by drugs
Assist patient to look for other modes of transportation in order to continue typical activities or employment
Review adverse drug reactions associated with the prescribed anticonvulsant with the patient and family members

25. Nursing Process: Implementation #9
Educating the patient and family (cont.)
Hydantoins:
Inform dentist and other primary health care providers of use of this drug
Brush and floss teeth after each meal and make periodic dental appointments for oral examination and care

26. Nursing Process: Implementation #10
Educating the patient and family (cont.)
Take medication with food to reduce GI upset
Thoroughly shake phenytoin suspension immediately before use
Do not take capsules that are discolored

27. Nursing Process: Implementation #11
Educating the patient and family (cont.)
Notify primary health care provider if any of the following occurs: skin rash; bleeding; swollen or tender gums; yellowish discoloration of the skin or eyes; unexplained fever; sore throat; unusual bleeding or bruising; persistent headache; malaise; or pregnancy

28. Nursing Process: Implementation #12
Educating the patient and family (cont.)
Succinimides:
If GI upset occurs, take drug with food or milk
Notify primary health care provider if any of the following occurs: skin rash; joint pain; unexplained fever; sore throat; usual bleeding or bruising; drowsiness; dizziness; blurred vision; or pregnancy

29. Nursing Process: Implementation #13
Educating the patient and family (cont.)
Oxazolidinediones:
Determine protective measures when exposed to ultraviolet light, sunlight
Notify primary health care provider if following reactions occur: visual disturbances; excessive drowsiness; dizziness; sore throat; fever; skin rash; pregnancy; malaise; easy bruising; epistaxis; bleeding tendencies

30. Nursing Process: Evaluation
Therapeutic effect is achieved and convulsions are controlled
No injury is evident
Adverse reactions are identified, reported, and managed successfully through appropriate nursing interventions
Patient verbalizes the importance of complying with the prescribed treatment regimen
Patient verbalizes an understanding of treatment modalities and the importance of continued follow-up care
Patient and family demonstrate an understanding of the drug regimen

31. Question #1 Is the following statement true or false?
Convulsion and seizure are terms often used interchangeably to describe sudden, involuntary muscle contractions due to changes in brain electrical activity.

32. Answer to Question #1 True
Convulsion and seizure are terms often used interchangeably to describe sudden, involuntary muscle contractions due to changes in brain electrical activity. Seizures may be caused by disease, injury, or metabolic changes or inherited at birth.

33. Question #2 Is the following statement true or false?
Anticonvulsant drugs are used to depress the abnormal nerve impulses discharged in the brain.

34. Answer to Question #2 True
Anticonvulsant drugs are used to depress the abnormal nerve impulses discharged in the brain. When discontinued, the drugs should be tapered down or seizure activity may return.