McKenna's Pharmacology for Nursing, 2e

363

C H A P T E R 2 3 Antiseizure agents

Evaluation

■ ■ Administer the drug with food to alleviate GI irritation if GI upset is a problem. ■ ■ Monitor for adverse effects and provide appropriate supportive care as needed to help the person cope with these effects. ■ ■ Monitor full blood count (FBC) before and periodically during therapy to detect bone marrow suppression early and provide appropriate interventions. ■ ■ Discontinue the drug if skin rash, bone marrow suppression or unusual depression or personality changes occur to prevent the development of more serious adverse effects. ■ ■ Discontinue the drug slowly, and never withdraw the drug quickly, because rapid withdrawal may precipitate absence seizures. ■ ■ Monitor for drug–drug interactions to arrange to adjust doses appropriately if any drug is added to or withdrawn from the drug regimen. ■ ■ Arrange for counselling for women of childbearing age who are taking these drugs. Because these drugs have the potential to cause serious damage to the fetus , women should understand the risk of birth defects and use barrier contraceptives to avoid pregnancy. ■ ■ Offer support and encouragement to help the person cope with the drug regimen. ■ ■ Provide thorough teaching, including drug name and prescribed dosage, as well as measures for avoidance of adverse effects and warning signs that may indicate possible problems to enhance knowledge about drug therapy and to promote compliance ; and the need for periodic blood tests to evaluate blood counts to reduce the risk of infection and for drug levels to evaluate therapeutic effectiveness and minimise the risk for toxicity . ■ ■ Suggest the wearing or carrying of a MedicAlert bracelet to alert emergency workers and healthcare providers about the use of an antiepileptic drug.

■■ Drugs used to treat generalised seizures include the hydantoins, barbiturates and benzodiazepines. ■■ Drugs used to treat absence seizures—a particular type of generalised seizure—include the hydantoins, succinimides, acetazolamide, sodium valproate and zonisamide. ■■ All of these drugs stabilise nerve membranes throughout the CNS to decrease excitability and hyperexcitability to stimulation. ■■ Adverse effects associated with these drugs reflect the CNS depression—lethargy, somnolence, fatigue, dry mouth, constipation and dizziness. Serious liver, bone marrow and dermatological problems can occur with specific drugs. ■ ■ Monitor response to the drug (decrease in incidence or absence of seizures; serum drug levels within the therapeutic range); evaluate for therapeutic blood levels (40 to 100 mcg/mL) for ethosuximide to ensure the most appropriate dose of the drug. ■ ■ Monitor for adverse effects (CNS changes, GI depression, urinary retention, arrhythmias, blood pressure changes, liver toxicity, bone marrow suppression, severe dermatological reactions). ■ ■ Evaluate the effectiveness of the teaching plan (person can give the drug name and dosage and name possible adverse effects to watch for and specific measures to prevent them; person is aware of the risk of birth defects and the need to carry information about the diagnosis and use of this drug). ■ ■ Monitor the effectiveness of comfort measures and compliance with the regimen.

KEY POINTS

CRITICAL THINKING SCENARIO Antiepileptic drugs

THE SITUATION J.M., an athletic, 18-year-old high school student, suffered his first seizure during maths class. He seemed attentive and alert, and then he suddenly slumped to the floor and suffered a full tonic–clonic (grand mal) seizure. The other students were frightened and did not know what to do. Fortunately, the teacher was familiar with seizures and quickly reacted to protect J.M. from hurting himself and to explain what was happening.

J.M. was diagnosed with idiopathic generalised epilepsy with tonic–clonic (grand mal) seizures. The combination of phenytoin and phenobarbitone that he began taking made him quite drowsy during the day. These drugs were unable to control the seizures, and he suffered three more seizures in the next month—one at school and two at home. J.M. is now undergoing re-evaluation for possible drug adjustment and counselling.