Chapter 19: Antiseizure Drugs & Epilepsy Treatment

Anticonvulsants, also known as antiseizure drugs, function by stabilizing nerve cell membranes to suppress abnormal impulses through three primary mechanisms: blocking sodium channels to delay neuron firing, inhibiting calcium influx, or augmenting the activity of gamma-aminobutyric acid (GABA), which is the brain's primary inhibitory neurotransmitter. The text details various drug classes, including hydantoins, long-acting barbiturates, succinimides, benzodiazepines, and iminostilbenes. A significant emphasis is placed on phenytoin, a widely used hydantoin that requires precise management because of its narrow therapeutic window of 10 to 20 mcg/mL. Levels exceeding this range can lead to toxicity, manifesting as ataxia or nystagmus, while levels below the range fail to prevent seizures. The chapter classifies seizures into generalized types, such as tonic-clonic and absence seizures, and partial types, noting that specific drugs are preferred for different classifications; for example, ethosuximide is the standard treatment for absence seizures, while valproic acid provides broad-spectrum control. Clinical emergencies like status epilepticus are highlighted, requiring immediate intravenous administration of fast-acting benzodiazepines like diazepam or lorazepam followed by longer-acting agents. Nursing responsibilities are central to the discussion, focusing on the necessity of monitoring blood counts for potential blood dyscrasias, assessing liver and renal function, and educating patients on the risks of abrupt medication withdrawal, which can trigger rebound seizures. Furthermore, the chapter addresses the unique challenges of seizure management during pregnancy, specifically the teratogenic risks of certain medications and the resulting need for supplemental vitamins K and D to prevent neonatal hemorrhage. Patient safety is reinforced through guidance on oral hygiene to manage gingival hyperplasia, the importance of wearing medical alert identification, and the avoidance of central nervous system depressants like alcohol that can exacerbate drug effects.