Copyright © 2008 Lippincott Williams & Wilkins. Introductory Clinical Pharmacology Chapter 31 Anticonvulsants

Copyright © 2008 Lippincott Williams & Wilkins. Anticonvulsants: Actions Benzodiazepines and barbiturates inhibit uptake of GABA at receptors Hydantoins stabilize hyperexcitability postsynaptically in motor cortex of brain Oxazolidinediones decrease repetitive synaptic transmission of nerve impulses Succinimides depress motor cortex creating higher threshold before nerves react to convulsive stimuli

Copyright © 2008 Lippincott Williams & Wilkins. Anticonvulsants: Uses Used prophylactically to prevent seizures following trauma, neurosurgery, or tumor Used in treatment of: –Seizures of all types; neuropathic pain; biopolar disorders; anxiety disorders

Copyright © 2008 Lippincott Williams & Wilkins. Anticonvulsants: Adverse Reactions Central nervous system reactions: Drowsiness; weakness; dizziness; headache; somnolence; nystagmus; ataxia; slurred speech Gastrointestinal reactions: Nausea; vomiting; anorexia; constipation; diarrhea; gingival hyperplasia Other: Skin rashes; pruritus; urticaria; urinary frequency; serious skin reactions; hematologic changes

Copyright © 2008 Lippincott Williams & Wilkins. Anticonvulsants: Contraindications Contraindicated in patients hypersensitive to the drugs –Phenytoin is contraindicated in patients with sinus bradycardia; sinoatrial block; Adams-Stokes syndrome; second and third-degree atrioventricular (AV) block; during pregnancy and lactation –Ethotoin (Pegatone) is contraindicated in patients with hepatic abnormalities

Copyright © 2008 Lippincott Williams & Wilkins. Anticonvulsants: Contraindications (cont’d) –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

Copyright © 2008 Lippincott Williams & Wilkins. Anticonvulsants: Precautions Used cautiously in patients with liver or kidney disease or neurologic disorders –Barbiturates are used with caution in patients with pulmonary disease and in hyperactive children –Benzodiazepines are used cautiously during pregnancy and in patients with psychoses; acute narrow-angle glaucoma; elderly or debilitated patients

Copyright © 2008 Lippincott Williams & Wilkins. Anticonvulsants: Precautions (cont’d) –Phenytoin is used cautiously in patients with hypotension, severe myocardial insufficiency, hepatic impairment –Trimethadione is used with caution in patients with eye disorders –Miscellaneous anticonvulsants are used cautiously in patients with glaucoma or increased intraocular pressure; a history of cardiac, renal, or liver dysfunction; and psychiatric disorders

Copyright © 2008 Lippincott Williams & Wilkins. Anticonvulsants: Interactions Interactant DrugEffect of Interaction Antibiotics/antifungalsIncreased effect of the anticonvulsant Tricyclic antidepressantsIncreased effect of the anticonvulsant SalicylatesIncreased effect of the anticonvulsant CimetidineIncreased effect of the anticonvulsant TheophyllineDecreased serum levels of the anticonvulsant

Copyright © 2008 Lippincott Williams & Wilkins. Anticonvulsants: Interactions (cont’d) Interactant DrugEffect of Interaction Antiseizure medicationsMay increase seizure activity Protease inhibitorsIncreased carbamazepine levels resulting in toxicity Oral contraceptivesDecreased effectiveness of birth control, resulting in breakthrough bleeding or pregnancy Analgesics or alcoholIncreased depressant effect Antidiabetic medicationsIncreased blood glucose levels

Copyright © 2008 Lippincott Williams & Wilkins. Nursing Process: Assessment 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

Copyright © 2008 Lippincott Williams & Wilkins. Nursing Process: Assessment 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

Copyright © 2008 Lippincott Williams & Wilkins. 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

Copyright © 2008 Lippincott Williams & Wilkins. Nursing Process: Implementation Promoting an optimal response to therapy –Make notation on the care plan, as well as informing 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

Copyright © 2008 Lippincott Williams & Wilkins. Nursing Process: Implementation Promoting an optimal response to therapy (cont’d) –Benzodiazepines Dosage of benzodiazepines is highly individualized; increase the dosage cautiously to avoid adverse reactions, particularly in elderly and debilitated patient Do not mix diazepam with other drugs

Copyright © 2008 Lippincott Williams & Wilkins. Nursing Process: Implementation Promoting an optimal response to therapy (cont’d) –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

Copyright © 2008 Lippincott Williams & Wilkins. Nursing Process: Implementation Promoting an optimal response to therapy (cont’d) –Succinimides Effective in controlling partial seizures, these drugs are given with food to prevent GI upset –Miscellaneous anticonvulsants Drug is absorbed rapidly when taken orally; should not be chewed but swallowed whole

Copyright © 2008 Lippincott Williams & Wilkins. Nursing Process: Implementation Monitoring and managing patient needs –Risk for injury The nurse should 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

Copyright © 2008 Lippincott Williams & Wilkins. Nursing Process: Implementation Monitoring and managing patient needs (cont’d) –Risk for impaired skin integrity Carefully examine all affected areas and provides 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

Copyright © 2008 Lippincott Williams & Wilkins. Nursing Process: Implementation Monitoring and managing patient needs (cont’d) –Impaired oral mucous membranes Periodically inspect mouth, teeth, gums of patients in a hospital or long-term clinical setting –Disturbed sensory perception: Visual Patient should stay out of sun if possible and wear sunscreens and protective clothing as needed until individual effects of drug are known

Copyright © 2008 Lippincott Williams & Wilkins. Nursing Process: Implementation Educating the patient and family –Nurse must assist patient and family to adjust to diagnosis of epilepsy –Instruct family members in care of patient before, during, and after seizure –Explain importance of restricting some activities until seizures are controlled by drugs –Assist patient in looking 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

Copyright © 2008 Lippincott Williams & Wilkins. Nursing Process: Implementation Educating the patient and family (cont’d) –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

Copyright © 2008 Lippincott Williams & Wilkins. Nursing Process: Implementation Educating the patient and family (cont’d) Take medication with food to reduce GI upset Thoroughly shake phenytoin suspension immediately before use Do not take capsules that are discolored

Copyright © 2008 Lippincott Williams & Wilkins. Nursing Process: Implementation Educating the patient and family (cont’d) Notify primary health care provider if any of the following occur: 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; pregnancy

Copyright © 2008 Lippincott Williams & Wilkins. Nursing Process: Implementation Educating the patient and family (cont’d) –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; unusual bleeding or bruising; drowsiness; dizziness, blurred vision; pregnancy

Copyright © 2008 Lippincott Williams & Wilkins. Nursing Process: Implementation Educating the patient and family (cont’d) –Oxazolidinediones Determine protective measures when exposed to ultraviolet light, sunlight Notify primary care provider if following occur: Visual disturbances; excessive drowsiness; dizziness; sore throat; fever; skin rash; pregnancy; malaise; easy bruising; epistaxis; bleeding tendencies

Copyright © 2008 Lippincott Williams & Wilkins. 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 understanding of treatment modalities and the importance of continued follow-up care Patient and family demonstrate an understanding of the drug regimen

Copyright © 2008 Lippincott Williams & Wilkins. End of Presentation